Lazy calculation of expensive file explaining diagnsotics and some caching to be used to share the diagnostic data (#58398)

src/compiler/program.ts

@@ -87,6 +87,7 @@ import {
     fileIncludeReasonToDiagnostics,
     FilePreprocessingDiagnostics,
     FilePreprocessingDiagnosticsKind,
+    FilePreprocessingLibReferenceDiagnostic,
     FileReference,
     filter,
     find,
@@ -1191,10 +1192,13 @@ export function getLibraryNameFromLibFileName(libFileName: string) {
     return "@typescript/lib-" + path;
 }
 
+function getLibNameFromLibReference(libReference: FileReference) {
+    return toFileNameLowerCase(libReference.fileName);
+}
+
 function getLibFileNameFromLibReference(libReference: FileReference) {
-    const libName = toFileNameLowerCase(libReference.fileName);
-    const libFileName = libMap.get(libName);
-    return { libName, libFileName };
+    const libName = getLibNameFromLibReference(libReference);
+    return libMap.get(libName);
 }
 
 interface DiagnosticCache<T extends Diagnostic> {
@@ -1500,6 +1504,16 @@ export const plainJSErrors = new Set<number>([
     Diagnostics.This_condition_will_always_return_0_since_JavaScript_compares_objects_by_reference_not_value.code,
 ]);
 
+interface LazyProgramDiagnosticExplainingFile {
+    file: SourceFile;
+    diagnostic: DiagnosticMessage;
+    args: DiagnosticArguments;
+}
+interface FileReasonToChainCache {
+    fileIncludeReasonDetails: DiagnosticMessageChain | undefined;
+    redirectInfo: DiagnosticMessageChain[] | undefined;
+    details?: DiagnosticMessageChain[];
+}
 /**
  * Determine if source file needs to be re-created even if its text hasn't changed
  */
@@ -1570,6 +1584,9 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
     let classifiableNames: Set<__String>;
     const ambientModuleNameToUnmodifiedFileName = new Map<string, string>();
     let fileReasons = createMultiMap<Path, FileIncludeReason>();
+    let filesWithReferencesProcessed: Set<Path> | undefined;
+    let fileReasonsToChain: Map<Path, FileReasonToChainCache> | undefined;
+    let reasonToRelatedInfo: Map<FileIncludeReason, DiagnosticWithLocation | false> | undefined;
     const cachedBindAndCheckDiagnosticsForFile: DiagnosticCache<Diagnostic> = {};
     const cachedDeclarationDiagnosticsForFile: DiagnosticCache<DiagnosticWithLocation> = {};
 
@@ -1620,6 +1637,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
      * Otherwise fileProcessingDiagnostics is correct locations so that the diagnostics can be reported in all structure use scenarios
      */
     const programDiagnostics = createDiagnosticCollection();
+    let lazyProgramDiagnosticExplainingFile: LazyProgramDiagnosticExplainingFile[] | undefined = [];
     const currentDirectory = host.getCurrentDirectory();
     const supportedExtensions = getSupportedExtensions(options);
     const supportedExtensionsWithJsonIfResolveJsonModule = getSupportedExtensionsWithJsonIfResolveJsonModule(options, supportedExtensions);
@@ -1866,6 +1884,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
         files = stableSort(processingDefaultLibFiles, compareDefaultLibFiles).concat(processingOtherFiles);
         processingDefaultLibFiles = undefined;
         processingOtherFiles = undefined;
+        filesWithReferencesProcessed = undefined;
     }
 
     // Release any files we have acquired in the old program but are
@@ -1996,21 +2015,6 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
 
     onProgramCreateComplete();
 
-    // Add file processingDiagnostics
-    fileProcessingDiagnostics?.forEach(diagnostic => {
-        switch (diagnostic.kind) {
-            case FilePreprocessingDiagnosticsKind.FilePreprocessingFileExplainingDiagnostic:
-                return programDiagnostics.add(createDiagnosticExplainingFile(diagnostic.file && getSourceFileByPath(diagnostic.file), diagnostic.fileProcessingReason, diagnostic.diagnostic, diagnostic.args || emptyArray));
-            case FilePreprocessingDiagnosticsKind.FilePreprocessingReferencedDiagnostic:
-                const { file, pos, end } = getReferencedFileLocation(program, diagnostic.reason) as ReferenceFileLocation;
-                return programDiagnostics.add(createFileDiagnostic(file, Debug.checkDefined(pos), Debug.checkDefined(end) - pos, diagnostic.diagnostic, ...diagnostic.args || emptyArray));
-            case FilePreprocessingDiagnosticsKind.ResolutionDiagnostics:
-                return diagnostic.diagnostics.forEach(d => programDiagnostics.add(d));
-            default:
-                Debug.assertNever(diagnostic);
-        }
-    });
-
     verifyCompilerOptions();
     performance.mark("afterProgram");
     performance.measure("Program", "beforeProgram", "afterProgram");
@@ -2018,6 +2022,56 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
 
     return program;
 
+    function updateAndGetProgramDiagnostics() {
+        if (lazyProgramDiagnosticExplainingFile) {
+            // Add file processingDiagnostics
+            fileProcessingDiagnostics?.forEach(diagnostic => {
+                switch (diagnostic.kind) {
+                    case FilePreprocessingDiagnosticsKind.FilePreprocessingFileExplainingDiagnostic:
+                        return programDiagnostics.add(
+                            createDiagnosticExplainingFile(
+                                diagnostic.file && getSourceFileByPath(diagnostic.file),
+                                diagnostic.fileProcessingReason,
+                                diagnostic.diagnostic,
+                                diagnostic.args || emptyArray,
+                            ),
+                        );
+                    case FilePreprocessingDiagnosticsKind.FilePreprocessingLibReferenceDiagnostic:
+                        return programDiagnostics.add(filePreprocessingLibreferenceDiagnostic(diagnostic));
+                    case FilePreprocessingDiagnosticsKind.ResolutionDiagnostics:
+                        return diagnostic.diagnostics.forEach(d => programDiagnostics.add(d));
+                    default:
+                        Debug.assertNever(diagnostic);
+                }
+            });
+            lazyProgramDiagnosticExplainingFile.forEach(({ file, diagnostic, args }) =>
+                programDiagnostics.add(
+                    createDiagnosticExplainingFile(file, /*fileProcessingReason*/ undefined, diagnostic, args),
+                )
+            );
+            lazyProgramDiagnosticExplainingFile = undefined;
+            fileReasonsToChain = undefined;
+            reasonToRelatedInfo = undefined;
+        }
+        return programDiagnostics;
+    }
+
+    function filePreprocessingLibreferenceDiagnostic({ reason }: FilePreprocessingLibReferenceDiagnostic) {
+        const { file, pos, end } = getReferencedFileLocation(program, reason) as ReferenceFileLocation;
+        const libReference = file.libReferenceDirectives[reason.index];
+        const libName = getLibNameFromLibReference(libReference);
+        const unqualifiedLibName = removeSuffix(removePrefix(libName, "lib."), ".d.ts");
+        const suggestion = getSpellingSuggestion(unqualifiedLibName, libs, identity);
+        return createFileDiagnostic(
+            file,
+            Debug.checkDefined(pos),
+            Debug.checkDefined(end) - pos,
+            suggestion ? Diagnostics.Cannot_find_lib_definition_for_0_Did_you_mean_1 : Diagnostics.Cannot_find_lib_definition_for_0,
+            libName,
+            suggestion!,
+        );
+    }
+
     function getResolvedModule(file: SourceFile, moduleName: string, mode: ResolutionMode) {
         return resolvedModules?.get(file.path)?.get(moduleName, mode);
     }
@@ -2881,7 +2935,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
             return emptyArray;
         }
 
-        const programDiagnosticsInFile = programDiagnostics.getDiagnostics(sourceFile.fileName);
+        const programDiagnosticsInFile = updateAndGetProgramDiagnostics().getDiagnostics(sourceFile.fileName);
         if (!sourceFile.commentDirectives?.length) {
             return programDiagnosticsInFile;
         }
@@ -3327,16 +3381,16 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
 
     function getOptionsDiagnostics(): SortedReadonlyArray<Diagnostic> {
         return sortAndDeduplicateDiagnostics(concatenate(
-            programDiagnostics.getGlobalDiagnostics(),
+            updateAndGetProgramDiagnostics().getGlobalDiagnostics(),
             getOptionsDiagnosticsOfConfigFile(),
         ));
     }
 
     function getOptionsDiagnosticsOfConfigFile() {
         if (!options.configFile) return emptyArray;
-        let diagnostics = programDiagnostics.getDiagnostics(options.configFile.fileName);
+        let diagnostics = updateAndGetProgramDiagnostics().getDiagnostics(options.configFile.fileName);
         forEachResolvedProjectReference(resolvedRef => {
-            diagnostics = concatenate(diagnostics, programDiagnostics.getDiagnostics(resolvedRef.sourceFile.fileName));
+            diagnostics = concatenate(diagnostics, updateAndGetProgramDiagnostics().getDiagnostics(resolvedRef.sourceFile.fileName));
         });
         return diagnostics;
     }
@@ -3514,7 +3568,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
     }
 
     function getLibFileFromReference(ref: FileReference) {
-        const { libFileName } = getLibFileNameFromLibReference(ref);
+        const libFileName = getLibFileNameFromLibReference(ref);
         const actualFileName = libFileName && resolvedLibReferences?.get(libFileName)?.actual;
         return actualFileName !== undefined ? getSourceFile(actualFileName) : undefined;
     }
@@ -3666,10 +3720,10 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
         const originalFileName = fileName;
         if (filesByName.has(path)) {
             const file = filesByName.get(path);
-            addFileIncludeReason(file || undefined, reason);
+            const addedReason = addFileIncludeReason(file || undefined, reason, /*checkExisting*/ true);
             // try to check if we've already seen this file but with a different casing in path
             // NOTE: this only makes sense for case-insensitive file systems, and only on files which are not redirected
-            if (file && !(options.forceConsistentCasingInFileNames === false)) {
+            if (file && addedReason && !(options.forceConsistentCasingInFileNames === false)) {
                 const checkedName = file.fileName;
                 const isRedirect = toPath(checkedName) !== toPath(fileName);
                 if (isRedirect) {
@@ -3746,7 +3800,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
                 const dupFile = createRedirectedSourceFile(fileFromPackageId, file!, fileName, path, toPath(fileName), originalFileName, sourceFileOptions);
                 redirectTargetsMap.add(fileFromPackageId.path, fileName);
                 addFileToFilesByName(dupFile, path, fileName, redirectedPath);
-                addFileIncludeReason(dupFile, reason);
+                addFileIncludeReason(dupFile, reason, /*checkExisting*/ false);
                 sourceFileToPackageName.set(path, packageIdToPackageName(packageId));
                 processingOtherFiles!.push(dupFile);
                 return dupFile;
@@ -3767,7 +3821,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
             file.originalFileName = originalFileName;
             file.packageJsonLocations = sourceFileOptions.packageJsonLocations?.length ? sourceFileOptions.packageJsonLocations : undefined;
             file.packageJsonScope = sourceFileOptions.packageJsonScope;
-            addFileIncludeReason(file, reason);
+            addFileIncludeReason(file, reason, /*checkExisting*/ false);
 
             if (host.useCaseSensitiveFileNames()) {
                 const pathLowerCase = toFileNameLowerCase(path);
@@ -3800,12 +3854,17 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
             else {
                 processingOtherFiles!.push(file);
             }
+            (filesWithReferencesProcessed ??= new Set()).add(file.path);
         }
         return file;
     }
 
-    function addFileIncludeReason(file: SourceFile | undefined, reason: FileIncludeReason) {
-        if (file) fileReasons.add(file.path, reason);
+    function addFileIncludeReason(file: SourceFile | undefined, reason: FileIncludeReason, checkExisting: boolean) {
+        if (file && (!checkExisting || !isReferencedFile(reason) || !filesWithReferencesProcessed?.has(reason.file))) {
+            fileReasons.add(file.path, reason);
+            return true;
+        }
+        return false;
     }
 
     function addFileToFilesByName(file: SourceFile | undefined, path: Path, fileName: string, redirectedPath: Path | undefined) {
@@ -4067,21 +4126,15 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
 
     function processLibReferenceDirectives(file: SourceFile) {
         forEach(file.libReferenceDirectives, (libReference, index) => {
-            const { libName, libFileName } = getLibFileNameFromLibReference(libReference);
+            const libFileName = getLibFileNameFromLibReference(libReference);
             if (libFileName) {
                 // we ignore any 'no-default-lib' reference set on this file.
                 processRootFile(pathForLibFile(libFileName), /*isDefaultLib*/ true, /*ignoreNoDefaultLib*/ true, { kind: FileIncludeKind.LibReferenceDirective, file: file.path, index });
             }
             else {
-                const unqualifiedLibName = removeSuffix(removePrefix(libName, "lib."), ".d.ts");
-                const suggestion = getSpellingSuggestion(unqualifiedLibName, libs, identity);
-                const diagnostic = suggestion ? Diagnostics.Cannot_find_lib_definition_for_0_Did_you_mean_1 : Diagnostics.Cannot_find_lib_definition_for_0;
-                const args = suggestion ? [libName, suggestion] : [libName];
                 (fileProcessingDiagnostics ||= []).push({
-                    kind: FilePreprocessingDiagnosticsKind.FilePreprocessingReferencedDiagnostic,
+                    kind: FilePreprocessingDiagnosticsKind.FilePreprocessingLibReferenceDiagnostic,
                     reason: { kind: FileIncludeKind.LibReferenceDirective, file: file.path, index },
-                    diagnostic,
-                    args,
                 });
             }
         });
@@ -4166,7 +4219,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
             if (!sourceFile.isDeclarationFile) {
                 const absoluteSourceFilePath = host.getCanonicalFileName(getNormalizedAbsolutePath(sourceFile.fileName, currentDirectory));
                 if (absoluteSourceFilePath.indexOf(absoluteRootDirectoryPath) !== 0) {
-                    addProgramDiagnosticExplainingFile(
+                    addLazyProgramDiagnosticExplainingFile(
                         sourceFile,
                         Diagnostics.File_0_is_not_under_rootDir_1_rootDir_is_expected_to_contain_all_source_files,
                         [sourceFile.fileName, rootDirectory],
@@ -4289,7 +4342,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
             for (const file of files) {
                 // Ignore file that is not emitted
                 if (sourceFileMayBeEmitted(file, program) && !rootPaths.has(file.path)) {
-                    addProgramDiagnosticExplainingFile(
+                    addLazyProgramDiagnosticExplainingFile(
                         file,
                         Diagnostics.File_0_is_not_listed_within_the_file_list_of_project_1_Projects_must_list_all_files_or_use_an_include_pattern,
                         [file.fileName, options.configFilePath || ""],
@@ -4679,38 +4732,122 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
         });
     }
 
-    function createDiagnosticExplainingFile(file: SourceFile | undefined, fileProcessingReason: FileIncludeReason | undefined, diagnostic: DiagnosticMessage, args: DiagnosticArguments | undefined): Diagnostic {
+    function createDiagnosticExplainingFile(file: SourceFile | undefined, fileProcessingReason: FileIncludeReason | undefined, diagnostic: DiagnosticMessage, args: DiagnosticArguments): Diagnostic {
+        let seenReasons: Set<FileIncludeReason> | undefined;
+        const reasons = file && fileReasons.get(file.path);
         let fileIncludeReasons: DiagnosticMessageChain[] | undefined;
-        let relatedInfo: Diagnostic[] | undefined;
+        let relatedInfo: DiagnosticWithLocation[] | undefined;
         let locationReason = isReferencedFile(fileProcessingReason) ? fileProcessingReason : undefined;
-        if (file) fileReasons.get(file.path)?.forEach(processReason);
+        let fileIncludeReasonDetails: DiagnosticMessageChain | undefined;
+        let redirectInfo: DiagnosticMessageChain[] | undefined;
+        let cachedChain = file && fileReasonsToChain?.get(file.path);
+        let chain: DiagnosticMessageChain | undefined;
+        if (cachedChain) {
+            if (cachedChain.fileIncludeReasonDetails) {
+                seenReasons = new Set(reasons);
+                reasons?.forEach(populateRelatedInfo);
+            }
+            else {
+                reasons?.forEach(processReason);
+            }
+            redirectInfo = cachedChain.redirectInfo;
+        }
+        else {
+            reasons?.forEach(processReason);
+            redirectInfo = file && explainIfFileIsRedirectAndImpliedFormat(file, getCompilerOptionsForFile(file));
+        }
+
         if (fileProcessingReason) processReason(fileProcessingReason);
+        const processedExtraReason = seenReasons?.size !== reasons?.length;
+
         // If we have location and there is only one reason file is in which is the location, dont add details for file include
-        if (locationReason && fileIncludeReasons?.length === 1) fileIncludeReasons = undefined;
+        if (locationReason && seenReasons?.size === 1) seenReasons = undefined;
+
+        if (seenReasons && cachedChain) {
+            if (cachedChain.details && !processedExtraReason) {
+                chain = chainDiagnosticMessages(cachedChain.details, diagnostic, ...args || emptyArray);
+            }
+            else if (cachedChain.fileIncludeReasonDetails) {
+                if (!processedExtraReason) {
+                    if (!cachedFileIncludeDetailsHasProcessedExtraReason()) {
+                        fileIncludeReasonDetails = cachedChain.fileIncludeReasonDetails;
+                    }
+                    else {
+                        fileIncludeReasons = cachedChain.fileIncludeReasonDetails.next!.slice(0, reasons!.length);
+                    }
+                }
+                else {
+                    if (!cachedFileIncludeDetailsHasProcessedExtraReason()) {
+                        fileIncludeReasons = [...cachedChain.fileIncludeReasonDetails.next!, fileIncludeReasons![0]];
+                    }
+                    else {
+                        fileIncludeReasons = append(cachedChain.fileIncludeReasonDetails.next!.slice(0, reasons!.length), fileIncludeReasons![0]);
+                    }
+                }
+            }
+        }
+
+        if (!chain) {
+            if (!fileIncludeReasonDetails) fileIncludeReasonDetails = seenReasons && chainDiagnosticMessages(fileIncludeReasons, Diagnostics.The_file_is_in_the_program_because_Colon);
+            chain = chainDiagnosticMessages(
+                redirectInfo ?
+                    fileIncludeReasonDetails ? [fileIncludeReasonDetails, ...redirectInfo] : redirectInfo :
+                    fileIncludeReasonDetails,
+                diagnostic,
+                ...args || emptyArray,
+            );
+        }
+
+        // This is chain's next contains:
+        //   - File is in program because:
+        //      - Files reasons listed
+        //      - extra reason if its not already processed - this happens in case sensitive file system where files differ in casing and we are giving reasons for two files so reason is not in file's reason
+        //     fyi above whole secton is ommited if we have single reason and we are reporting at that reason's location
+        //   - redirect and additional information about file
+        // So cache result if we havent ommited file include reasons
+        if (file) {
+            if (cachedChain) {
+                // Cache new fileIncludeDetails if we have update
+                // Or if we had cached with more details than the reasons
+                if (!cachedChain.fileIncludeReasonDetails || (!processedExtraReason && fileIncludeReasonDetails)) {
+                    cachedChain.fileIncludeReasonDetails = fileIncludeReasonDetails;
+                }
+            }
+            else {
+                (fileReasonsToChain ??= new Map()).set(file.path, cachedChain = { fileIncludeReasonDetails, redirectInfo });
+            }
+            // If we didnt compute extra file include reason , cache the details to use directly
+            if (!cachedChain.details && !processedExtraReason) cachedChain.details = chain.next;
+        }
+
         const location = locationReason && getReferencedFileLocation(program, locationReason);
-        const fileIncludeReasonDetails = fileIncludeReasons && chainDiagnosticMessages(fileIncludeReasons, Diagnostics.The_file_is_in_the_program_because_Colon);
-        const optionsForFile = file && getCompilerOptionsForFile(file) || options;
-        const redirectInfo = file && explainIfFileIsRedirectAndImpliedFormat(file, optionsForFile);
-        const chain = chainDiagnosticMessages(redirectInfo ? fileIncludeReasonDetails ? [fileIncludeReasonDetails, ...redirectInfo] : redirectInfo : fileIncludeReasonDetails, diagnostic, ...args || emptyArray);
         return location && isReferenceFileLocation(location) ?
             createFileDiagnosticFromMessageChain(location.file, location.pos, location.end - location.pos, chain, relatedInfo) :
             createCompilerDiagnosticFromMessageChain(chain, relatedInfo);
 
         function processReason(reason: FileIncludeReason) {
-            (fileIncludeReasons ||= []).push(fileIncludeReasonToDiagnostics(program, reason));
+            if (seenReasons?.has(reason)) return;
+            (seenReasons ??= new Set()).add(reason);
+            (fileIncludeReasons ??= []).push(fileIncludeReasonToDiagnostics(program, reason));
+            populateRelatedInfo(reason);
+        }
+
+        function populateRelatedInfo(reason: FileIncludeReason) {
             if (!locationReason && isReferencedFile(reason)) {
                 // Report error at first reference file or file currently in processing and dont report in related information
                 locationReason = reason;
             }
             else if (locationReason !== reason) {
-                relatedInfo = append(relatedInfo, fileIncludeReasonToRelatedInformation(reason));
+                relatedInfo = append(relatedInfo, getFileIncludeReasonToRelatedInformation(reason));
             }
-            // Remove fileProcessingReason if its already included in fileReasons of the program
-            if (reason === fileProcessingReason) fileProcessingReason = undefined;
+        }
+
+        function cachedFileIncludeDetailsHasProcessedExtraReason() {
+            return cachedChain!.fileIncludeReasonDetails!.next?.length !== reasons?.length;
         }
     }
 
-    function addFilePreprocessingFileExplainingDiagnostic(file: SourceFile | undefined, fileProcessingReason: FileIncludeReason, diagnostic: DiagnosticMessage, args?: DiagnosticArguments) {
+    function addFilePreprocessingFileExplainingDiagnostic(file: SourceFile | undefined, fileProcessingReason: FileIncludeReason, diagnostic: DiagnosticMessage, args: DiagnosticArguments) {
         (fileProcessingDiagnostics ||= []).push({
             kind: FilePreprocessingDiagnosticsKind.FilePreprocessingFileExplainingDiagnostic,
             file: file && file.path,
@@ -4720,8 +4857,14 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
         });
     }
 
-    function addProgramDiagnosticExplainingFile(file: SourceFile, diagnostic: DiagnosticMessage, args?: DiagnosticArguments) {
-        programDiagnostics.add(createDiagnosticExplainingFile(file, /*fileProcessingReason*/ undefined, diagnostic, args));
+    function addLazyProgramDiagnosticExplainingFile(file: SourceFile, diagnostic: DiagnosticMessage, args: DiagnosticArguments) {
+        lazyProgramDiagnosticExplainingFile!.push({ file, diagnostic, args });
+    }
+
+    function getFileIncludeReasonToRelatedInformation(reason: FileIncludeReason) {
+        let relatedInfo = reasonToRelatedInfo?.get(reason);
+        if (relatedInfo === undefined) (reasonToRelatedInfo ??= new Map()).set(reason, relatedInfo = fileIncludeReasonToRelatedInformation(reason) ?? false);
+        return relatedInfo || undefined;
     }
 
     function fileIncludeReasonToRelatedInformation(reason: FileIncludeReason): DiagnosticWithLocation | undefined {

src/compiler/types.ts

@@ -4608,26 +4608,24 @@ export type FileIncludeReason =
 
 /** @internal */
 export const enum FilePreprocessingDiagnosticsKind {
-    FilePreprocessingReferencedDiagnostic,
+    FilePreprocessingLibReferenceDiagnostic,
     FilePreprocessingFileExplainingDiagnostic,
     ResolutionDiagnostics,
 }
 
 /** @internal */
-export interface FilePreprocessingReferencedDiagnostic {
-    kind: FilePreprocessingDiagnosticsKind.FilePreprocessingReferencedDiagnostic;
-    reason: ReferencedFile;
-    diagnostic: DiagnosticMessage;
-    args?: DiagnosticArguments;
+export interface FilePreprocessingLibReferenceDiagnostic {
+    kind: FilePreprocessingDiagnosticsKind.FilePreprocessingLibReferenceDiagnostic;
+    reason: ReferencedFile & { kind: FileIncludeKind.LibReferenceDirective; };
 }
 
 /** @internal */
 export interface FilePreprocessingFileExplainingDiagnostic {
     kind: FilePreprocessingDiagnosticsKind.FilePreprocessingFileExplainingDiagnostic;
-    file?: Path;
+    file: Path | undefined;
     fileProcessingReason: FileIncludeReason;
     diagnostic: DiagnosticMessage;
-    args?: DiagnosticArguments;
+    args: DiagnosticArguments;
 }
 
 /** @internal */
@@ -4637,7 +4635,7 @@ export interface ResolutionDiagnostics {
 }
 
 /** @internal */
-export type FilePreprocessingDiagnostics = FilePreprocessingReferencedDiagnostic | FilePreprocessingFileExplainingDiagnostic | ResolutionDiagnostics;
+export type FilePreprocessingDiagnostics = FilePreprocessingLibReferenceDiagnostic | FilePreprocessingFileExplainingDiagnostic | ResolutionDiagnostics;
 
 /** @internal */
 export const enum EmitOnly {

src/compiler/watchPublic.ts

@@ -594,6 +594,7 @@ export function createWatchProgram<T extends BuilderProgram>(host: WatchCompiler
             });
             parsedConfigs = undefined;
         }
+        builderProgram = undefined!;
     }
 
     function getResolutionCache() {

src/testRunner/unittests/helpers.ts

@@ -21,6 +21,7 @@ export interface NamedSourceText {
 export interface ProgramWithSourceTexts extends ts.Program {
     sourceTexts?: readonly NamedSourceText[];
     host: TestCompilerHost;
+    version: number;
 }
 
 export interface TestCompilerHost extends ts.CompilerHost {
@@ -102,7 +103,7 @@ function createSourceFileWithText(fileName: string, sourceText: SourceText, targ
     return file;
 }
 
-export function createTestCompilerHost(texts: readonly NamedSourceText[], target: ts.ScriptTarget, oldProgram?: ProgramWithSourceTexts, useGetSourceFileByPath?: boolean) {
+export function createTestCompilerHost(texts: readonly NamedSourceText[], target: ts.ScriptTarget, oldProgram?: ProgramWithSourceTexts, useGetSourceFileByPath?: boolean, useCaseSensitiveFileNames?: boolean) {
     const files = ts.arrayToMap(texts, t => t.name, t => {
         if (oldProgram) {
             let oldFile = oldProgram.getSourceFile(t.name) as SourceFileWithText;
@@ -115,14 +116,15 @@ export function createTestCompilerHost(texts: readonly NamedSourceText[], target
         }
         return createSourceFileWithText(t.name, t.text, target);
     });
-    const useCaseSensitiveFileNames = ts.sys && ts.sys.useCaseSensitiveFileNames;
+    if (useCaseSensitiveFileNames === undefined) useCaseSensitiveFileNames = ts.sys && ts.sys.useCaseSensitiveFileNames;
     const getCanonicalFileName = ts.createGetCanonicalFileName(useCaseSensitiveFileNames);
+    const filesByPath = ts.mapEntries(files, (fileName, file) => [ts.toPath(fileName, "", getCanonicalFileName), file]);
     const trace: string[] = [];
     const result: TestCompilerHost = {
         trace: s => trace.push(s),
         getTrace: () => trace,
         clearTrace: () => trace.length = 0,
-        getSourceFile: fileName => files.get(fileName),
+        getSourceFile: fileName => filesByPath.get(ts.toPath(fileName, "", getCanonicalFileName)),
         getDefaultLibFileName: () => "lib.d.ts",
         writeFile: ts.notImplemented,
         getCurrentDirectory: () => "",
@@ -130,37 +132,48 @@ export function createTestCompilerHost(texts: readonly NamedSourceText[], target
         getCanonicalFileName,
         useCaseSensitiveFileNames: () => useCaseSensitiveFileNames,
         getNewLine: () => ts.sys ? ts.sys.newLine : newLine,
-        fileExists: fileName => files.has(fileName),
+        fileExists: fileName => filesByPath.has(ts.toPath(fileName, "", getCanonicalFileName)),
         readFile: fileName => {
-            const file = files.get(fileName);
+            const file = filesByPath.get(ts.toPath(fileName, "", getCanonicalFileName));
             return file && file.text;
         },
     };
     if (useGetSourceFileByPath) {
-        const filesByPath = ts.mapEntries(files, (fileName, file) => [ts.toPath(fileName, "", getCanonicalFileName), file]);
         result.getSourceFileByPath = (_fileName, path) => filesByPath.get(path);
     }
     return result;
 }
 
-export function newProgram(texts: NamedSourceText[], rootNames: string[], options: ts.CompilerOptions, useGetSourceFileByPath?: boolean): ProgramWithSourceTexts {
-    const host = createTestCompilerHost(texts, options.target!, /*oldProgram*/ undefined, useGetSourceFileByPath);
-    const program = ts.createProgram(rootNames, options, host) as ProgramWithSourceTexts;
-    program.sourceTexts = texts;
-    program.host = host;
-    return program;
+export function newProgram(texts: NamedSourceText[], rootNames: string[], options: ts.CompilerOptions, useGetSourceFileByPath?: boolean, useCaseSensitiveFileNames?: boolean): ProgramWithSourceTexts {
+    const host = createTestCompilerHost(texts, options.target!, /*oldProgram*/ undefined, useGetSourceFileByPath, useCaseSensitiveFileNames);
+    return programToProgramWithSourceTexts(
+        ts.createProgram(rootNames, options, host),
+        texts,
+        host,
+        1,
+    );
 }
 
-export function updateProgram(oldProgram: ProgramWithSourceTexts, rootNames: readonly string[], options: ts.CompilerOptions, updater: (files: NamedSourceText[]) => void, newTexts?: NamedSourceText[], useGetSourceFileByPath?: boolean) {
+function programToProgramWithSourceTexts(program: ts.Program, texts: NamedSourceText[], host: TestCompilerHost, version: number): ProgramWithSourceTexts {
+    const result = program as ProgramWithSourceTexts;
+    result.sourceTexts = texts;
+    result.host = host;
+    result.version = version;
+    return result;
+}
+
+export function updateProgram(oldProgram: ProgramWithSourceTexts, rootNames: readonly string[], options: ts.CompilerOptions, updater: (files: NamedSourceText[]) => void, newTexts?: NamedSourceText[], useGetSourceFileByPath?: boolean, useCaseSensitiveFileNames?: boolean) {
     if (!newTexts) {
         newTexts = oldProgram.sourceTexts!.slice(0);
     }
     updater(newTexts);
-    const host = createTestCompilerHost(newTexts, options.target!, oldProgram, useGetSourceFileByPath);
-    const program = ts.createProgram(rootNames, options, host, oldProgram) as ProgramWithSourceTexts;
-    program.sourceTexts = newTexts;
-    program.host = host;
-    return program;
+    const host = createTestCompilerHost(newTexts, options.target!, oldProgram, useGetSourceFileByPath, useCaseSensitiveFileNames);
+    return programToProgramWithSourceTexts(
+        ts.createProgram(rootNames, options, host, oldProgram),
+        newTexts,
+        host,
+        oldProgram.version + 1,
+    );
 }
 
 export function updateProgramText(files: readonly NamedSourceText[], fileName: string, newProgramText: string) {

src/testRunner/unittests/helpers/forceConsistentCasingInFileNames.ts

@@ -0,0 +1,33 @@
+import { dedent } from "../../_namespaces/Utils";
+import { jsonToReadableText } from "../helpers";
+import {
+    FsContents,
+    libContent,
+} from "./contents";
+import { libFile } from "./virtualFileSystemWithWatch";
+
+export function getFsContentsForMultipleErrorsForceConsistentCasingInFileNames(): FsContents {
+    return {
+        "/home/src/projects/project/src/struct.d.ts": dedent`
+            import * as xs1 from "fp-ts/lib/Struct";
+            import * as xs2 from "fp-ts/lib/struct";
+            import * as xs3 from "./Struct";
+            import * as xs4 from "./struct";
+        `,
+        "/home/src/projects/project/src/anotherFile.ts": dedent`
+            import * as xs1 from "fp-ts/lib/Struct";
+            import * as xs2 from "fp-ts/lib/struct";
+            import * as xs3 from "./Struct";
+            import * as xs4 from "./struct";
+        `,
+        "/home/src/projects/project/src/oneMore.ts": dedent`
+            import * as xs1 from "fp-ts/lib/Struct";
+            import * as xs2 from "fp-ts/lib/struct";
+            import * as xs3 from "./Struct";
+            import * as xs4 from "./struct";
+        `,
+        "/home/src/projects/project/tsconfig.json": jsonToReadableText({}),
+        "/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts": `export function foo(): void`,
+        [libFile.path]: libContent,
+    };
+}

src/testRunner/unittests/helpers/libraryResolution.ts

@@ -91,3 +91,46 @@ export function getCommandLineArgsForLibResolution(withoutConfig: true | undefin
         ["project1/core.d.ts", "project1/utils.d.ts", "project1/file.ts", "project1/index.ts", "project1/file2.ts", "--lib", "es5,dom", "--traceResolution", "--explainFiles"] :
         ["-p", "project1", "--explainFiles"];
 }
+
+function getFsContentsForLibResolutionUnknown(): FsContents {
+    return {
+        "/home/src/projects/project1/utils.d.ts": `export const y = 10;`,
+        "/home/src/projects/project1/file.ts": `export const file = 10;`,
+        "/home/src/projects/project1/core.d.ts": `export const core = 10;`,
+        "/home/src/projects/project1/index.ts": `export const x = "type1";`,
+        "/home/src/projects/project1/file2.ts": dedent`
+            /// <reference lib="webworker2"/>
+            /// <reference lib="unknownlib"/>
+            /// <reference lib="scripthost"/>
+        `,
+        "/home/src/projects/project1/tsconfig.json": jsonToReadableText({
+            compilerOptions: {
+                composite: true,
+                traceResolution: true,
+            },
+        }),
+        "/home/src/lib/lib.d.ts": libContent,
+        "/home/src/lib/lib.webworker.d.ts": "interface WebWorkerInterface { }",
+        "/home/src/lib/lib.scripthost.d.ts": "interface ScriptHostInterface { }",
+    };
+}
+
+export function getFsForLibResolutionUnknown() {
+    return loadProjectFromFiles(
+        getFsContentsForLibResolutionUnknown(),
+        {
+            cwd: "/home/src/projects",
+            executingFilePath: "/home/src/lib/tsc.js",
+        },
+    );
+}
+
+export function getSysForLibResolutionUnknown() {
+    return createWatchedSystem(
+        getFsContentsForLibResolutionUnknown(),
+        {
+            currentDirectory: "/home/src/projects",
+            executingFilePath: "/home/src/lib/tsc.js",
+        },
+    );
+}

src/testRunner/unittests/reuseProgramStructure.ts

@@ -19,7 +19,8 @@ import {
     libFile,
 } from "./helpers/virtualFileSystemWithWatch";
 
-describe("unittests:: Reuse program structure:: General", () => {
+describe("unittests:: reuseProgramStructure:: General", () => {
+    type ProgramToBaseline = ts.Program & Pick<ProgramWithSourceTexts, "version">;
     function baselineCache<File, T>(
         baselines: string[],
         cacheType: string,
@@ -40,8 +41,21 @@ describe("unittests:: Reuse program structure:: General", () => {
             baselines.push(`${key}: ${mode ? ts.getNameOfCompilerOptionValue(mode, ts.moduleOptionDeclaration.type) + ": " : ""}${jsonToReadableText(resolved)}`);
         }
     }
-    function baselineProgram(baselines: string[], program: ts.Program, host?: TestCompilerHost) {
-        baselines.push(`Program Reused:: ${(ts as any).StructureIsReused[program.structureIsReused]}`);
+
+    function baselineDiagnostics(baselines: string[], program: ProgramToBaseline, skipHeader?: boolean) {
+        if (!skipHeader) {
+            baselines.push(`Program ${program.version} Reused:: ${(ts as any).StructureIsReused[program.structureIsReused]}`);
+            baselines.push(`Diagnostics:`);
+        }
+        baselines.push(ts.formatDiagnostics(program.getSemanticDiagnostics(), {
+            getCurrentDirectory: () => program.getCurrentDirectory(),
+            getNewLine: () => "\n",
+            getCanonicalFileName: ts.createGetCanonicalFileName(program.useCaseSensitiveFileNames()),
+        }));
+        baselines.push("", "");
+    }
+    function baselineProgram(baselines: string[], program: ProgramToBaseline, host?: TestCompilerHost, skipDiagnostics?: boolean) {
+        baselines.push(`Program ${program.version} Reused:: ${(ts as any).StructureIsReused[program.structureIsReused]}`);
         program.getSourceFiles().forEach(f => {
             baselines.push(`File: ${f.fileName}`, f.text);
             baselineCache(baselines, "resolvedModules", f, program.forEachResolvedModule);
@@ -55,12 +69,12 @@ describe("unittests:: Reuse program structure:: General", () => {
         baselines.push("");
         baselines.push(`MissingPaths:: ${jsonToReadableText(ts.arrayFrom(program.getMissingFilePaths().values()))}`);
         baselines.push("");
-        baselines.push(ts.formatDiagnostics(program.getSemanticDiagnostics(), {
-            getCurrentDirectory: () => program.getCurrentDirectory(),
-            getNewLine: () => "\n",
-            getCanonicalFileName: ts.createGetCanonicalFileName(program.useCaseSensitiveFileNames()),
-        }));
-        baselines.push("", "");
+        if (!skipDiagnostics) {
+            baselineDiagnostics(baselines, program, /*skipHeader*/ true);
+        }
+        else {
+            baselines.push("Skipped diagnostics", "", "");
+        }
     }
 
     function runBaseline(scenario: string, baselines: readonly string[]) {
@@ -281,7 +295,8 @@ describe("unittests:: Reuse program structure:: General", () => {
         ];
         const host = createTestCompilerHost(files, target);
         const options: ts.CompilerOptions = { target, typeRoots: ["/types"] };
-        const program1 = ts.createProgram(["/a.ts"], options, host);
+        const program1 = ts.createProgram(["/a.ts"], options, host) as ProgramToBaseline;
+        program1.version = 1;
         let sourceFile = program1.getSourceFile("/a.ts")!;
         const baselines: string[] = [];
         baselineProgram(baselines, program1, host);
@@ -293,7 +308,8 @@ describe("unittests:: Reuse program structure:: General", () => {
                 return fileName === sourceFile.fileName ? sourceFile : program1.getSourceFile(fileName);
             },
         };
-        const program2 = ts.createProgram(["/a.ts"], options, updateHost, program1);
+        const program2 = ts.createProgram(["/a.ts"], options, updateHost, program1) as ProgramToBaseline;
+        program2.version = 2;
         baselineProgram(baselines, program2, updateHost);
         baselines.push(`parent pointers are not altered: ${sourceFile.statements[2].getSourceFile() === sourceFile}`);
         runBaseline("works with updated SourceFiles", baselines);
@@ -554,15 +570,217 @@ describe("unittests:: Reuse program structure:: General", () => {
             verifyRedirects(/*useGetSourceFileByPath*/ true);
         });
     });
+
+    it("forceConsistentCasingInFileNames:: handles file preprocessing dignostics", () => {
+        const files = [
+            {
+                name: "/src/project/src/struct.d.ts",
+                text: SourceText.New(
+                    "",
+                    "",
+                    Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs2 from "fp-ts/lib/struct";
+                        import * as xs3 from "./Struct";
+                        import * as xs4 from "./struct";
+                    `,
+                ),
+            },
+            {
+                name: "/src/project/src/anotherFile.ts",
+                text: SourceText.New(
+                    "",
+                    "",
+                    Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs2 from "fp-ts/lib/struct";
+                        import * as xs3 from "./Struct";
+                        import * as xs4 from "./struct";
+                    `,
+                ),
+            },
+            {
+                name: "/src/project/src/oneMore.ts",
+                text: SourceText.New(
+                    "",
+                    "",
+                    Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs2 from "fp-ts/lib/struct";
+                        import * as xs3 from "./Struct";
+                        import * as xs4 from "./struct";
+                    `,
+                ),
+            },
+            {
+                name: "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+                text: SourceText.New("", "", `export function foo(): void`),
+            },
+        ];
+
+        const options: ts.CompilerOptions = { target, moduleResolution: ts.ModuleResolutionKind.Node10 };
+        const rootNames = files.map(f => f.name);
+        const program1 = newProgram(files, rootNames, options, /*useGetSourceFileByPath*/ undefined, /*useCaseSensitiveFileNames*/ false);
+        const baselines: string[] = [];
+        baselineProgram(baselines, program1);
+
+        const program2 = updateProgram(
+            program1,
+            rootNames,
+            options,
+            files => {
+                files[0].text = files[0].text.updateProgram(files[0].text.getFullText() + "export const y = 10;");
+            },
+            /*newTexts*/ undefined,
+            /*useGetSourceFileByPath*/ undefined,
+            /*useCaseSensitiveFileNames*/ false,
+        );
+        baselineProgram(baselines, program2);
+
+        const program3 = updateProgram(
+            program2,
+            rootNames,
+            options,
+            files => {
+                files[0].text = files[0].text.updateProgram(Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs2 from "fp-ts/lib/struct";
+                        import * as xs3 from "./Struct";
+                    `);
+            },
+            /*newTexts*/ undefined,
+            /*useGetSourceFileByPath*/ undefined,
+            /*useCaseSensitiveFileNames*/ false,
+        );
+        baselineProgram(baselines, program3);
+        runBaseline("handles file preprocessing dignostics", baselines);
+    });
+
+    it("forceConsistentCasingInFileNames:: handles file preprocessing dignostics when diagnostics are not queried", () => {
+        const files = [
+            {
+                name: "/src/project/src/struct.d.ts",
+                text: SourceText.New(
+                    "",
+                    "",
+                    Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs2 from "fp-ts/lib/struct";
+                        import * as xs3 from "./Struct";
+                        import * as xs4 from "./struct";
+                    `,
+                ),
+            },
+            {
+                name: "/src/project/src/anotherFile.ts",
+                text: SourceText.New(
+                    "",
+                    "",
+                    Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs2 from "fp-ts/lib/struct";
+                        import * as xs3 from "./Struct";
+                        import * as xs4 from "./struct";
+                    `,
+                ),
+            },
+            {
+                name: "/src/project/src/oneMore.ts",
+                text: SourceText.New(
+                    "",
+                    "",
+                    Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs2 from "fp-ts/lib/struct";
+                        import * as xs3 from "./Struct";
+                        import * as xs4 from "./struct";
+                    `,
+                ),
+            },
+            {
+                name: "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+                text: SourceText.New("", "", `export function foo(): void`),
+            },
+        ];
+
+        const options: ts.CompilerOptions = { target, moduleResolution: ts.ModuleResolutionKind.Node10 };
+        const rootNames = files.map(f => f.name);
+        const program1 = newProgram(files, rootNames, options, /*useGetSourceFileByPath*/ undefined, /*useCaseSensitiveFileNames*/ false);
+        const baselines: string[] = [];
+        baselineProgram(baselines, program1, /*host*/ undefined, /*skipDiagnostics*/ true);
+
+        const program2 = updateProgram(
+            program1,
+            rootNames,
+            options,
+            files => {
+                files[0].text = files[0].text.updateProgram(files[0].text.getFullText() + "export const y = 10;");
+            },
+            /*newTexts*/ undefined,
+            /*useGetSourceFileByPath*/ undefined,
+            /*useCaseSensitiveFileNames*/ false,
+        );
+        baselineProgram(baselines, program2, /*host*/ undefined, /*skipDiagnostics*/ true);
+        baselineDiagnostics(baselines, program1);
+
+        const program3 = updateProgram(
+            program2,
+            rootNames,
+            options,
+            files => {
+                files[0].text = files[0].text.updateProgram(files[0].text.getFullText() + "export const z = 10;");
+            },
+            /*newTexts*/ undefined,
+            /*useGetSourceFileByPath*/ undefined,
+            /*useCaseSensitiveFileNames*/ false,
+        );
+        baselineProgram(baselines, program3);
+        baselineDiagnostics(baselines, program2);
+
+        const program4 = updateProgram(
+            program3,
+            rootNames,
+            options,
+            files => {
+                files[0].text = files[0].text.updateProgram(Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs2 from "fp-ts/lib/struct";
+                        import * as xs3 from "./Struct";
+                    `);
+            },
+            /*newTexts*/ undefined,
+            /*useGetSourceFileByPath*/ undefined,
+            /*useCaseSensitiveFileNames*/ false,
+        );
+        baselineProgram(baselines, program4, /*host*/ undefined, /*skipDiagnostics*/ true);
+
+        const program5 = updateProgram(
+            program4,
+            rootNames,
+            options,
+            files => {
+                files[0].text = files[0].text.updateProgram(Utils.dedent`
+                        import * as xs1 from "fp-ts/lib/Struct";
+                        import * as xs3 from "./Struct";
+                    `);
+            },
+            /*newTexts*/ undefined,
+            /*useGetSourceFileByPath*/ undefined,
+            /*useCaseSensitiveFileNames*/ false,
+        );
+        baselineProgram(baselines, program5);
+        baselineDiagnostics(baselines, program4);
+        runBaseline("handles file preprocessing dignostics when diagnostics are not queried", baselines);
+    });
 });
 
-describe("unittests:: Reuse program structure:: host is optional", () => {
+describe("unittests:: reuseProgramStructure:: host is optional", () => {
     it("should work if host is not provided", () => {
         ts.createProgram([], {});
     });
 });
 
-describe("unittests:: Reuse program structure:: isProgramUptoDate", () => {
+describe("unittests:: reuseProgramStructure:: isProgramUptoDate::", () => {
     function getWhetherProgramIsUptoDate(
         program: ts.Program,
         newRootFileNames: string[],

src/testRunner/unittests/tsc/forceConsistentCasingInFileNames.ts

@@ -1,4 +1,5 @@
-import * as Utils from "../../_namespaces/Utils";
+import { dedent } from "../../_namespaces/Utils";
+import { getFsContentsForMultipleErrorsForceConsistentCasingInFileNames } from "../helpers/forceConsistentCasingInFileNames";
 import { verifyTsc } from "../helpers/tsc";
 import { loadProjectFromFiles } from "../helpers/vfs";
 
@@ -9,7 +10,7 @@ describe("unittests:: tsc:: forceConsistentCasingInFileNames::", () => {
         commandLineArgs: ["/src/project/src/struct.d.ts", "--forceConsistentCasingInFileNames", "--explainFiles"],
         fs: () =>
             loadProjectFromFiles({
-                "/src/project/src/struct.d.ts": Utils.dedent`
+                "/src/project/src/struct.d.ts": dedent`
                     import * as xs1 from "fp-ts/lib/Struct";
                     import * as xs2 from "fp-ts/lib/struct";
                     import * as xs3 from "./Struct";
@@ -18,4 +19,11 @@ describe("unittests:: tsc:: forceConsistentCasingInFileNames::", () => {
                 "/src/project/node_modules/fp-ts/lib/struct.d.ts": `export function foo(): void`,
             }),
     });
+
+    verifyTsc({
+        scenario: "forceConsistentCasingInFileNames",
+        subScenario: "when file is included from multiple places with different casing",
+        commandLineArgs: ["-p", "/home/src/projects/project/tsconfig.json", "--explainFiles"],
+        fs: () => loadProjectFromFiles(getFsContentsForMultipleErrorsForceConsistentCasingInFileNames()),
+    });
 });

src/testRunner/unittests/tsc/libraryResolution.ts

@@ -1,6 +1,7 @@
 import {
     getCommandLineArgsForLibResolution,
     getFsForLibResolution,
+    getFsForLibResolutionUnknown,
 } from "../helpers/libraryResolution";
 import { verifyTsc } from "../helpers/tsc";
 
@@ -18,4 +19,12 @@ describe("unittests:: tsc:: libraryResolution:: library file resolution", () =>
     verify(/*libRedirection*/ true);
     verify(/*libRedirection*/ undefined, /*withoutConfig*/ true);
     verify(/*libRedirection*/ true, /*withoutConfig*/ true);
+
+    verifyTsc({
+        scenario: "libraryResolution",
+        subScenario: "unknown lib",
+        fs: () => getFsForLibResolutionUnknown(),
+        commandLineArgs: getCommandLineArgsForLibResolution(/*withoutConfig*/ undefined),
+        baselinePrograms: true,
+    });
 });

src/testRunner/unittests/tscWatch/forceConsistentCasingInFileNames.ts

@@ -1,5 +1,6 @@
-import * as Utils from "../../_namespaces/Utils";
+import { dedent } from "../../_namespaces/Utils";
 import { jsonToReadableText } from "../helpers";
+import { getFsContentsForMultipleErrorsForceConsistentCasingInFileNames } from "../helpers/forceConsistentCasingInFileNames";
 import {
     TscWatchCompileChange,
     verifyTscWatch,
@@ -11,7 +12,7 @@ import {
     SymLink,
 } from "../helpers/virtualFileSystemWithWatch";
 
-describe("unittests:: tsc-watch:: forceConsistentCasingInFileNames", () => {
+describe("unittests:: tsc-watch:: forceConsistentCasingInFileNames::", () => {
     const loggerFile: File = {
         path: `/user/username/projects/myproject/logger.ts`,
         content: `export class logger { }`,
@@ -334,7 +335,7 @@ a;b;
                         ".": "./dist/index.js",
                     },
                 }),
-                "/Users/name/projects/web/index.ts": Utils.dedent`
+                "/Users/name/projects/web/index.ts": dedent`
                     import * as me from "@this/package";
                     me.thing();
                     export function thing(): void {}
@@ -365,10 +366,10 @@ a;b;
                     type: "module",
                     exports: "./src/index.ts",
                 }),
-                "/Users/name/projects/lib-boilerplate/src/index.ts": Utils.dedent`
+                "/Users/name/projects/lib-boilerplate/src/index.ts": dedent`
                     export function thing(): void {}
                 `,
-                "/Users/name/projects/lib-boilerplate/test/basic.spec.ts": Utils.dedent`
+                "/Users/name/projects/lib-boilerplate/test/basic.spec.ts": dedent`
                     import { thing } from 'lib-boilerplate'
                 `,
                 "/Users/name/projects/lib-boilerplate/tsconfig.json": jsonToReadableText({
@@ -382,4 +383,35 @@ a;b;
                 "/a/lib/lib.es2021.full.d.ts": libFile.content,
             }, { currentDirectory: "/Users/name/projects/lib-boilerplate" }),
     });
+
+    verifyTscWatch({
+        scenario: "forceConsistentCasingInFileNames",
+        subScenario: "when file is included from multiple places with different casing",
+        commandLineArgs: ["-w", "--explainFiles"],
+        sys: () =>
+            createWatchedSystem(
+                getFsContentsForMultipleErrorsForceConsistentCasingInFileNames(),
+                { currentDirectory: "/home/src/projects/project" },
+            ),
+        edits: [
+            {
+                caption: "change to reuse imports",
+                edit: sys => sys.appendFile("/home/src/projects/project/src/struct.d.ts", "export const y = 10;"),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+            {
+                caption: "change to update imports",
+                edit: sys =>
+                    sys.writeFile(
+                        "/home/src/projects/project/src/struct.d.ts",
+                        dedent`
+                            import * as xs1 from "fp-ts/lib/Struct";
+                            import * as xs2 from "fp-ts/lib/struct";
+                            import * as xs3 from "./Struct";
+                        `,
+                    ),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+        ],
+    });
 });

src/testRunner/unittests/tscWatch/libraryResolution.ts

@@ -1,7 +1,9 @@
+import { dedent } from "../../_namespaces/Utils";
 import { jsonToReadableText } from "../helpers";
 import {
     getCommandLineArgsForLibResolution,
     getSysForLibResolution,
+    getSysForLibResolutionUnknown,
 } from "../helpers/libraryResolution";
 import {
     TscWatchCompileChange,
@@ -9,7 +11,7 @@ import {
     verifyTscWatch,
 } from "../helpers/tscWatch";
 
-describe("unittests:: tsc-watch:: libraryResolution", () => {
+describe("unittests:: tsc-watch:: libraryResolution::", () => {
     function commandLineArgs(withoutConfig: true | undefined) {
         return ["-w", ...getCommandLineArgsForLibResolution(withoutConfig), "--extendedDiagnostics"];
     }
@@ -147,4 +149,47 @@ describe("unittests:: tsc-watch:: libraryResolution", () => {
     }
     verify();
     verify(/*withoutConfig*/ true);
+
+    verifyTscWatch({
+        scenario: "libraryResolution",
+        subScenario: "unknwon lib",
+        sys: () => getSysForLibResolutionUnknown(),
+        commandLineArgs: commandLineArgs(/*withoutConfig*/ undefined),
+        edits: [
+            {
+                caption: "edit index",
+                edit: sys => sys.appendFile("/home/src/projects/project1/index.ts", "export const xyz = 10;"),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+            {
+                caption: "delete core",
+                edit: sys => sys.deleteFile("/home/src/projects/project1/core.d.ts"),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+            {
+                caption: "remove unknown lib",
+                edit: sys =>
+                    sys.writeFile(
+                        "/home/src/projects/project1/file2.ts",
+                        dedent`
+                            /// <reference lib="webworker2"/>
+                            /// <reference lib="scripthost"/>
+                        `,
+                    ),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+            {
+                caption: "correct webworker lib",
+                edit: sys =>
+                    sys.writeFile(
+                        "/home/src/projects/project1/file2.ts",
+                        dedent`
+                            /// <reference lib="webworker"/>
+                            /// <reference lib="scripthost"/>
+                        `,
+                    ),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+        ],
+    });
 });

src/testRunner/unittests/tsserver/forceConsistentCasingInFileNames.ts

@@ -1,10 +1,12 @@
 import * as ts from "../../_namespaces/ts";
 import { dedent } from "../../_namespaces/Utils";
 import { jsonToReadableText } from "../helpers";
+import { getFsContentsForMultipleErrorsForceConsistentCasingInFileNames } from "../helpers/forceConsistentCasingInFileNames";
 import {
     baselineTsserverLogs,
     closeFilesForSession,
     openFilesForSession,
+    protocolFileLocationFromSubstring,
     protocolTextSpanFromSubstring,
     TestSession,
     verifyGetErrRequest,
@@ -16,7 +18,7 @@ import {
     SymLink,
 } from "../helpers/virtualFileSystemWithWatch";
 
-describe("unittests:: tsserver:: forceConsistentCasingInFileNames", () => {
+describe("unittests:: tsserver:: forceConsistentCasingInFileNames::", () => {
     it("works when extends is specified with a case insensitive file system", () => {
         const rootPath = "/Users/username/dev/project";
         const file1: File = {
@@ -328,4 +330,63 @@ describe("unittests:: tsserver:: forceConsistentCasingInFileNames", () => {
         verifyDirSymlink("when import and directory symlink target agree but do not match disk", `/user/username/projects/myproject/XY`, `/user/username/projects/myproject/Xy`, `./Xy`);
         verifyDirSymlink("when import, directory symlink target, and disk are all different", `/user/username/projects/myproject/XY`, `/user/username/projects/myproject/Xy`, `./xY`);
     });
+
+    it("when file is included from multiple places with different casing", () => {
+        const host = createServerHost(getFsContentsForMultipleErrorsForceConsistentCasingInFileNames());
+        const session = new TestSession(host);
+        const file = "/home/src/projects/project/src/struct.d.ts";
+        let fileText = host.readFile(file)!;
+        openFilesForSession([{ file, projectRootPath: "/home/src/projects/project" }], session);
+        verifyGetErrRequest({ session, files: [file] });
+
+        // Update file without import but dont get errors:
+        updateFile(fileText + "\nexport const y = 10;");
+        goToDef();
+
+        // Update file without import and get errors:
+        updateFile(fileText + "\nexport const yy = 10;");
+        verifyGetErrRequest({ session, files: [file] });
+
+        // Remove one import, dont get errors
+        updateFile(dedent`
+            import * as xs1 from "fp-ts/lib/Struct";
+            import * as xs2 from "fp-ts/lib/struct";
+            import * as xs3 from "./Struct";
+        `);
+        goToDef();
+
+        // Remove import, get errors
+        updateFile(dedent`
+            import * as xs1 from "fp-ts/lib/Struct";
+            import * as xs3 from "./struct";
+        `);
+        verifyGetErrRequest({ session, files: [file] });
+        baselineTsserverLogs("forceConsistentCasingInFileNames", "when file is included from multiple places with different casing", session);
+
+        function updateFile(newText: string) {
+            session.executeCommandSeq<ts.server.protocol.UpdateOpenRequest>({
+                command: ts.server.protocol.CommandTypes.UpdateOpen,
+                arguments: {
+                    changedFiles: [{
+                        fileName: file,
+                        textChanges: [{
+                            newText,
+                            ...protocolTextSpanFromSubstring(
+                                fileText,
+                                fileText,
+                            ),
+                        }],
+                    }],
+                },
+            });
+            fileText = newText;
+        }
+
+        function goToDef() {
+            session.executeCommandSeq<ts.server.protocol.DefinitionRequest>({
+                command: ts.server.protocol.CommandTypes.Definition,
+                arguments: protocolFileLocationFromSubstring({ path: file, content: fileText }, `"fp-ts/lib/Struct"`),
+            });
+        }
+    });
 });

tests/baselines/reference/reuseProgramStructure/can-reuse-ambient-module-declarations-from-non-modified-files.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /a/b/app.ts
 
 import * as fs from 'fs'
@@ -81,7 +81,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: /a/b/app.ts
 
 import * as fs from 'fs'
@@ -136,7 +136,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Completely
+Program 3 Reused:: Completely
 File: /a/b/app.ts
 
 import * as fs from 'fs'

tests/baselines/reference/reuseProgramStructure/can-reuse-module-resolutions-from-non-modified-files.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: a1.ts
 
 
@@ -138,7 +138,7 @@ node_modules/@types/typerefs2/index.d.ts(3,13): error TS2451: Cannot redeclare b
 
 
 
-Program Reused:: SafeModules
+Program 2 Reused:: SafeModules
 File: a1.ts
 
 
@@ -284,7 +284,7 @@ node_modules/@types/typerefs2/index.d.ts(3,13): error TS2451: Cannot redeclare b
 
 
 
-Program Reused:: SafeModules
+Program 3 Reused:: SafeModules
 File: a1.ts
 
 
@@ -413,7 +413,7 @@ node_modules/@types/typerefs2/index.d.ts(3,13): error TS2451: Cannot redeclare b
 
 
 
-Program Reused:: SafeModules
+Program 4 Reused:: SafeModules
 File: a1.ts
 
 
@@ -542,7 +542,7 @@ node_modules/@types/typerefs2/index.d.ts(3,13): error TS2451: Cannot redeclare b
 
 
 
-Program Reused:: Completely
+Program 5 Reused:: Completely
 File: a1.ts
 
 
@@ -653,7 +653,7 @@ node_modules/@types/typerefs2/index.d.ts(3,13): error TS2451: Cannot redeclare b
 
 
 
-Program Reused:: SafeModules
+Program 6 Reused:: SafeModules
 File: a1.ts
 
 
@@ -782,7 +782,7 @@ node_modules/@types/typerefs2/index.d.ts(3,13): error TS2451: Cannot redeclare b
 
 
 
-Program Reused:: SafeModules
+Program 7 Reused:: SafeModules
 File: a1.ts
 
 

tests/baselines/reference/reuseProgramStructure/change-affects-a-single-module-of-a-package.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/b/internal.d.ts
 
 
@@ -67,7 +67,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: /node_modules/b/internal.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/change-affects-imports.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -42,7 +42,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: SafeModules
+Program 2 Reused:: SafeModules
 File: c.ts
 
 import x from 'b'

tests/baselines/reference/reuseProgramStructure/change-affects-tripleslash-references.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -42,7 +42,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: SafeModules
+Program 2 Reused:: SafeModules
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/change-affects-type-directives.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -42,7 +42,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: SafeModules
+Program 2 Reused:: SafeModules
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/change-affects-type-references.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -55,7 +55,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: SafeModules
+Program 2 Reused:: SafeModules
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/change-does-not-affect-imports-or-type-refs.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -42,7 +42,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/change-doesnot-affect-type-references.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -55,7 +55,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/config-path-changes.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -46,7 +46,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/fetches-imports-after-npm-install.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: file1.ts
 
 import * as a from "a";
@@ -63,7 +63,7 @@ file1.ts(2,20): error TS2307: Cannot find module 'a' or its corresponding type d
 
 
 
-Program Reused:: SafeModules
+Program 2 Reused:: SafeModules
 File: node_modules/a/index.d.ts
 
 export declare let x: number;

tests/baselines/reference/reuseProgramStructure/handles-file-preprocessing-dignostics.js

@@ -0,0 +1,990 @@
+Program 1 Reused:: Not
+File: /src/project/node_modules/fp-ts/lib/Struct.d.ts
+
+
+export function foo(): void
+
+File: /src/project/src/struct.d.ts
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+./struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/struct.ts",
+    "/src/project/src/struct.tsx"
+  ]
+}
+
+File: /src/project/src/anotherFile.ts
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+./struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/struct.ts",
+    "/src/project/src/struct.tsx"
+  ]
+}
+
+File: /src/project/src/oneMore.ts
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+./struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/struct.ts",
+    "/src/project/src/struct.tsx"
+  ]
+}
+
+
+MissingPaths:: [
+  "lib.d.ts"
+]
+
+/src/project/src/anotherFile.ts(4,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/anotherFile.ts(5,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+/src/project/src/oneMore.ts(4,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/oneMore.ts(5,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+/src/project/src/struct.d.ts(3,22): error TS1261: Already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' differs from file name '/src/project/node_modules/fp-ts/lib/struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/struct.d.ts(4,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/struct.d.ts(5,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+
+
+
+Program 2 Reused:: Completely
+File: /src/project/node_modules/fp-ts/lib/Struct.d.ts
+
+
+export function foo(): void
+
+File: /src/project/src/struct.d.ts
+
+
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+export const y = 10;
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+./struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/struct.ts",
+    "/src/project/src/struct.tsx"
+  ]
+}
+
+File: /src/project/src/anotherFile.ts
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+./struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/struct.ts",
+    "/src/project/src/struct.tsx"
+  ]
+}
+
+File: /src/project/src/oneMore.ts
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+./struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/struct.ts",
+    "/src/project/src/struct.tsx"
+  ]
+}
+
+
+MissingPaths:: [
+  "lib.d.ts"
+]
+
+/src/project/src/anotherFile.ts(4,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/anotherFile.ts(5,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+/src/project/src/oneMore.ts(4,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/oneMore.ts(5,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+/src/project/src/struct.d.ts(5,22): error TS1261: Already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' differs from file name '/src/project/node_modules/fp-ts/lib/struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/struct.d.ts(6,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/struct.d.ts(7,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+
+
+
+Program 3 Reused:: SafeModules
+File: /src/project/node_modules/fp-ts/lib/Struct.d.ts
+
+
+export function foo(): void
+
+File: /src/project/src/struct.d.ts
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+
+File: /src/project/src/anotherFile.ts
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+./struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/struct.ts",
+    "/src/project/src/struct.tsx"
+  ]
+}
+
+File: /src/project/src/oneMore.ts
+
+
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+resolvedModules:
+fp-ts/lib/Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/Struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/Struct.ts",
+    "/src/project/node_modules/fp-ts/lib/Struct.tsx"
+  ]
+}
+fp-ts/lib/struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/node_modules/fp-ts/lib/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": true,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/fp-ts/package.json",
+    "/src/project/src/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.ts",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.tsx",
+    "/src/project/src/node_modules/fp-ts/lib/struct/index.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/package.json",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct.d.ts",
+    "/src/project/src/node_modules/@types/fp-ts/lib/struct/index.d.ts",
+    "/src/project/node_modules/fp-ts/lib/struct/package.json",
+    "/src/project/node_modules/fp-ts/package.json",
+    "/src/project/node_modules/fp-ts/lib/struct.ts",
+    "/src/project/node_modules/fp-ts/lib/struct.tsx"
+  ]
+}
+./Struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/Struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/Struct.ts",
+    "/src/project/src/Struct.tsx"
+  ]
+}
+./struct: {
+  "resolvedModule": {
+    "resolvedFileName": "/src/project/src/struct.d.ts",
+    "extension": ".d.ts",
+    "isExternalLibraryImport": false,
+    "resolvedUsingTsExtension": false
+  },
+  "failedLookupLocations": [
+    "/src/project/src/struct.ts",
+    "/src/project/src/struct.tsx"
+  ]
+}
+
+
+MissingPaths:: [
+  "lib.d.ts"
+]
+
+/src/project/src/anotherFile.ts(4,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/anotherFile.ts(5,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+/src/project/src/oneMore.ts(4,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/oneMore.ts(5,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+/src/project/src/struct.d.ts(3,22): error TS1261: Already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' differs from file name '/src/project/node_modules/fp-ts/lib/struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/struct.d.ts(4,22): error TS1149: File name '/src/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/src/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/src/project/src/oneMore.ts'
+    Root file specified for compilation
+/src/project/src/struct.d.ts(5,22): error TS1149: File name '/src/project/src/Struct.d.ts' differs from already included file name '/src/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Root file specified for compilation
+    Imported via "./Struct" from file '/src/project/src/struct.d.ts'
+    Imported via "./Struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./struct" from file '/src/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/src/project/src/oneMore.ts'
+    Imported via "./struct" from file '/src/project/src/oneMore.ts'
+
+

tests/baselines/reference/reuseProgramStructure/missing-file-is-created.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -41,7 +41,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/missing-files-remain-missing.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -41,7 +41,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/module-kind-changes.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -42,7 +42,7 @@ a.ts(4,23): error TS2688: Cannot find type definition file for 'typerefs'.
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/redirect-no-change.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 
@@ -113,7 +113,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: /node_modules/a/node_modules/x/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/redirect-previous-duplicate-packages.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 
@@ -115,7 +115,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/redirect-target-changes.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 
@@ -113,7 +113,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/redirect-underlying-changes.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 
@@ -113,7 +113,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/redirect-with-getSourceFileByPath-no-change.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 
@@ -113,7 +113,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: /node_modules/a/node_modules/x/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/redirect-with-getSourceFileByPath-previous-duplicate-packages.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 
@@ -115,7 +115,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/redirect-with-getSourceFileByPath-target-changes.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 
@@ -113,7 +113,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/redirect-with-getSourceFileByPath-underlying-changes.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 
@@ -113,7 +113,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Not
+Program 2 Reused:: Not
 File: /node_modules/a/node_modules/x/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/resolution-cache-follows-imports.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: b.ts
 
 
@@ -27,7 +27,7 @@ a.ts(2,17): error TS2306: File 'b.ts' is not a module.
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: b.ts
 
 
@@ -56,7 +56,7 @@ a.ts(2,17): error TS2306: File 'b.ts' is not a module.
 
 
 
-Program Reused:: SafeModules
+Program 3 Reused:: SafeModules
 File: a.ts
 
 
@@ -70,7 +70,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: SafeModules
+Program 4 Reused:: SafeModules
 File: b.ts
 
 

tests/baselines/reference/reuseProgramStructure/resolved-type-directives-cache-follows-type-directives.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /types/typedefs/index.d.ts
 
 
@@ -29,7 +29,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: /types/typedefs/index.d.ts
 
 
@@ -60,7 +60,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: SafeModules
+Program 3 Reused:: SafeModules
 File: /a.ts
 
 
@@ -74,7 +74,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: SafeModules
+Program 4 Reused:: SafeModules
 File: /types/typedefs/index.d.ts
 
 

tests/baselines/reference/reuseProgramStructure/resolvedImports-after-re-using-an-ambient-external-module-declaration.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /a.ts
 
 
@@ -21,7 +21,7 @@ MissingPaths:: [
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: /a.ts
 
 

tests/baselines/reference/reuseProgramStructure/rootdir-changes.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: c.ts
 
 
@@ -44,7 +44,7 @@ b.ts(1,22): error TS6059: File 'c.ts' is not under 'rootDir' '/a/b'. 'rootDir' i
 
 
 
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: c.ts
 
 

tests/baselines/reference/reuseProgramStructure/works-with-updated-SourceFiles.js

@@ -1,4 +1,4 @@
-Program Reused:: Not
+Program 1 Reused:: Not
 File: /a.ts
 
 
@@ -22,7 +22,7 @@ MissingPaths:: [
 
 
 parent pointers are updated: true
-Program Reused:: Completely
+Program 2 Reused:: Completely
 File: /a.ts
 'use strict';
 

tests/baselines/reference/tsc/forceConsistentCasingInFileNames/when-file-is-included-from-multiple-places-with-different-casing.js

@@ -0,0 +1,339 @@
+currentDirectory:: / useCaseSensitiveFileNames: false
+Input::
+//// [/a/lib/lib.d.ts]
+/// <reference no-default-lib="true"/>
+interface Boolean {}
+interface Function {}
+interface CallableFunction {}
+interface NewableFunction {}
+interface IArguments {}
+interface Number { toExponential: any; }
+interface Object {}
+interface RegExp {}
+interface String { charAt: any; }
+interface Array<T> { length: number; [n: number]: T; }
+interface ReadonlyArray<T> {}
+declare const console: { log(msg: any): void; };
+
+//// [/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts]
+export function foo(): void
+
+//// [/home/src/projects/project/src/anotherFile.ts]
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+
+//// [/home/src/projects/project/src/oneMore.ts]
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+
+//// [/home/src/projects/project/src/struct.d.ts]
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+
+//// [/home/src/projects/project/tsconfig.json]
+{}
+
+//// [/lib/lib.d.ts]
+/// <reference no-default-lib="true"/>
+interface Boolean {}
+interface Function {}
+interface CallableFunction {}
+interface NewableFunction {}
+interface IArguments {}
+interface Number { toExponential: any; }
+interface Object {}
+interface RegExp {}
+interface String { charAt: any; }
+interface Array<T> { length: number; [n: number]: T; }
+interface ReadonlyArray<T> {}
+declare const console: { log(msg: any): void; };
+
+
+
+Output::
+/lib/tsc -p /home/src/projects/project/tsconfig.json --explainFiles
+home/src/projects/project/src/anotherFile.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  home/src/projects/project/src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+home/src/projects/project/src/anotherFile.ts:3:22 - error TS1261: Already included file name '/home/src/projects/project/src/Struct.d.ts' differs from file name '/home/src/projects/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+3 import * as xs3 from "./Struct";
+                       ~~~~~~~~~~
+
+  home/src/projects/project/src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+home/src/projects/project/src/anotherFile.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  home/src/projects/project/src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+home/src/projects/project/src/oneMore.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  home/src/projects/project/src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/anotherFile.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+home/src/projects/project/src/oneMore.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  home/src/projects/project/src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+home/src/projects/project/src/Struct.d.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  home/src/projects/project/src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/anotherFile.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+home/src/projects/project/src/Struct.d.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  home/src/projects/project/src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  home/src/projects/project/src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+lib/lib.d.ts
+  Default library for target 'es5'
+home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts
+  Imported via "fp-ts/lib/Struct" from file 'home/src/projects/project/src/anotherFile.ts'
+  Imported via "fp-ts/lib/struct" from file 'home/src/projects/project/src/anotherFile.ts'
+  Imported via "fp-ts/lib/Struct" from file 'home/src/projects/project/src/Struct.d.ts'
+  Imported via "fp-ts/lib/struct" from file 'home/src/projects/project/src/Struct.d.ts'
+  Imported via "fp-ts/lib/Struct" from file 'home/src/projects/project/src/oneMore.ts'
+  Imported via "fp-ts/lib/struct" from file 'home/src/projects/project/src/oneMore.ts'
+home/src/projects/project/src/Struct.d.ts
+  Imported via "./Struct" from file 'home/src/projects/project/src/anotherFile.ts'
+  Imported via "./Struct" from file 'home/src/projects/project/src/Struct.d.ts'
+  Imported via "./struct" from file 'home/src/projects/project/src/Struct.d.ts'
+  Imported via "./struct" from file 'home/src/projects/project/src/anotherFile.ts'
+  Imported via "./Struct" from file 'home/src/projects/project/src/oneMore.ts'
+  Imported via "./struct" from file 'home/src/projects/project/src/oneMore.ts'
+  Matched by default include pattern '**/*'
+home/src/projects/project/src/anotherFile.ts
+  Matched by default include pattern '**/*'
+home/src/projects/project/src/oneMore.ts
+  Matched by default include pattern '**/*'
+
+Found 7 errors in 3 files.
+
+Errors  Files
+     3  home/src/projects/project/src/anotherFile.ts:2
+     2  home/src/projects/project/src/oneMore.ts:2
+     2  home/src/projects/project/src/Struct.d.ts:2
+exitCode:: ExitStatus.DiagnosticsPresent_OutputsGenerated
+
+
+//// [/home/src/projects/project/src/anotherFile.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+
+
+//// [/home/src/projects/project/src/oneMore.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+
+

tests/baselines/reference/tsc/libraryResolution/unknown-lib.js

@@ -0,0 +1,331 @@
+currentDirectory:: /home/src/projects useCaseSensitiveFileNames: false
+Input::
+//// [/home/src/lib/lib.d.ts]
+/// <reference no-default-lib="true"/>
+interface Boolean {}
+interface Function {}
+interface CallableFunction {}
+interface NewableFunction {}
+interface IArguments {}
+interface Number { toExponential: any; }
+interface Object {}
+interface RegExp {}
+interface String { charAt: any; }
+interface Array<T> { length: number; [n: number]: T; }
+interface ReadonlyArray<T> {}
+declare const console: { log(msg: any): void; };
+
+//// [/home/src/lib/lib.scripthost.d.ts]
+interface ScriptHostInterface { }
+
+//// [/home/src/lib/lib.webworker.d.ts]
+interface WebWorkerInterface { }
+
+//// [/home/src/projects/project1/core.d.ts]
+export const core = 10;
+
+//// [/home/src/projects/project1/file.ts]
+export const file = 10;
+
+//// [/home/src/projects/project1/file2.ts]
+/// <reference lib="webworker2"/>
+/// <reference lib="unknownlib"/>
+/// <reference lib="scripthost"/>
+
+
+//// [/home/src/projects/project1/index.ts]
+export const x = "type1";
+
+//// [/home/src/projects/project1/tsconfig.json]
+{
+  "compilerOptions": {
+    "composite": true,
+    "traceResolution": true
+  }
+}
+
+//// [/home/src/projects/project1/utils.d.ts]
+export const y = 10;
+
+
+
+Output::
+/home/src/lib/tsc -p project1 --explainFiles
+File '/home/src/projects/project1/package.json' does not exist.
+File '/home/src/projects/package.json' does not exist.
+File '/home/src/package.json' does not exist.
+File '/home/package.json' does not exist.
+File '/package.json' does not exist.
+File '/home/src/projects/project1/package.json' does not exist according to earlier cached lookups.
+File '/home/src/projects/package.json' does not exist according to earlier cached lookups.
+File '/home/src/package.json' does not exist according to earlier cached lookups.
+File '/home/package.json' does not exist according to earlier cached lookups.
+File '/package.json' does not exist according to earlier cached lookups.
+File '/home/src/projects/project1/package.json' does not exist according to earlier cached lookups.
+File '/home/src/projects/package.json' does not exist according to earlier cached lookups.
+File '/home/src/package.json' does not exist according to earlier cached lookups.
+File '/home/package.json' does not exist according to earlier cached lookups.
+File '/package.json' does not exist according to earlier cached lookups.
+======== Resolving module '@typescript/lib-scripthost' from '/home/src/projects/project1/__lib_node_modules_lookup_lib.scripthost.d.ts__.ts'. ========
+Explicitly specified module resolution kind: 'Node10'.
+Loading module '@typescript/lib-scripthost' from 'node_modules' folder, target file types: TypeScript, Declaration.
+Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.
+Directory '/home/src/projects/project1/node_modules' does not exist, skipping all lookups in it.
+Scoped package detected, looking in 'typescript__lib-scripthost'
+Directory '/home/src/projects/node_modules' does not exist, skipping all lookups in it.
+Scoped package detected, looking in 'typescript__lib-scripthost'
+Directory '/home/src/node_modules' does not exist, skipping all lookups in it.
+Scoped package detected, looking in 'typescript__lib-scripthost'
+Directory '/home/node_modules' does not exist, skipping all lookups in it.
+Scoped package detected, looking in 'typescript__lib-scripthost'
+Directory '/node_modules' does not exist, skipping all lookups in it.
+Scoped package detected, looking in 'typescript__lib-scripthost'
+Loading module '@typescript/lib-scripthost' from 'node_modules' folder, target file types: JavaScript.
+Searching all ancestor node_modules directories for fallback extensions: JavaScript.
+Directory '/home/src/projects/project1/node_modules' does not exist, skipping all lookups in it.
+Directory '/home/src/projects/node_modules' does not exist, skipping all lookups in it.
+Directory '/home/src/node_modules' does not exist, skipping all lookups in it.
+Directory '/home/node_modules' does not exist, skipping all lookups in it.
+Directory '/node_modules' does not exist, skipping all lookups in it.
+======== Module name '@typescript/lib-scripthost' was not resolved. ========
+File '/home/src/lib/package.json' does not exist.
+File '/home/src/package.json' does not exist according to earlier cached lookups.
+File '/home/package.json' does not exist according to earlier cached lookups.
+File '/package.json' does not exist according to earlier cached lookups.
+File '/home/src/projects/project1/package.json' does not exist according to earlier cached lookups.
+File '/home/src/projects/package.json' does not exist according to earlier cached lookups.
+File '/home/src/package.json' does not exist according to earlier cached lookups.
+File '/home/package.json' does not exist according to earlier cached lookups.
+File '/package.json' does not exist according to earlier cached lookups.
+File '/home/src/projects/project1/package.json' does not exist according to earlier cached lookups.
+File '/home/src/projects/package.json' does not exist according to earlier cached lookups.
+File '/home/src/package.json' does not exist according to earlier cached lookups.
+File '/home/package.json' does not exist according to earlier cached lookups.
+File '/package.json' does not exist according to earlier cached lookups.
+File '/home/src/lib/package.json' does not exist according to earlier cached lookups.
+File '/home/src/package.json' does not exist according to earlier cached lookups.
+File '/home/package.json' does not exist according to earlier cached lookups.
+File '/package.json' does not exist according to earlier cached lookups.
+project1/file2.ts:1:21 - error TS2727: Cannot find lib definition for 'webworker2'. Did you mean 'webworker'?
+
+1 /// <reference lib="webworker2"/>
+                      ~~~~~~~~~~
+
+project1/file2.ts:2:21 - error TS2726: Cannot find lib definition for 'unknownlib'.
+
+2 /// <reference lib="unknownlib"/>
+                      ~~~~~~~~~~
+
+../lib/lib.d.ts
+  Default library for target 'es5'
+../lib/lib.scripthost.d.ts
+  Library referenced via 'scripthost' from file 'project1/file2.ts'
+project1/core.d.ts
+  Matched by default include pattern '**/*'
+project1/file.ts
+  Matched by default include pattern '**/*'
+project1/file2.ts
+  Matched by default include pattern '**/*'
+project1/index.ts
+  Matched by default include pattern '**/*'
+project1/utils.d.ts
+  Matched by default include pattern '**/*'
+
+Found 2 errors in the same file, starting at: project1/file2.ts:1
+
+exitCode:: ExitStatus.DiagnosticsPresent_OutputsGenerated
+Program root files: [
+  "/home/src/projects/project1/core.d.ts",
+  "/home/src/projects/project1/file.ts",
+  "/home/src/projects/project1/file2.ts",
+  "/home/src/projects/project1/index.ts",
+  "/home/src/projects/project1/utils.d.ts"
+]
+Program options: {
+  "composite": true,
+  "traceResolution": true,
+  "project": "/home/src/projects/project1",
+  "explainFiles": true,
+  "configFilePath": "/home/src/projects/project1/tsconfig.json"
+}
+Program structureReused: Not
+Program files::
+/home/src/lib/lib.d.ts
+/home/src/lib/lib.scripthost.d.ts
+/home/src/projects/project1/core.d.ts
+/home/src/projects/project1/file.ts
+/home/src/projects/project1/file2.ts
+/home/src/projects/project1/index.ts
+/home/src/projects/project1/utils.d.ts
+
+Semantic diagnostics in builder refreshed for::
+/home/src/lib/lib.d.ts
+/home/src/lib/lib.scripthost.d.ts
+/home/src/projects/project1/core.d.ts
+/home/src/projects/project1/file.ts
+/home/src/projects/project1/file2.ts
+/home/src/projects/project1/index.ts
+/home/src/projects/project1/utils.d.ts
+
+Shape signatures in builder refreshed for::
+/home/src/lib/lib.d.ts (used version)
+/home/src/lib/lib.scripthost.d.ts (used version)
+/home/src/projects/project1/core.d.ts (used version)
+/home/src/projects/project1/file.ts (computed .d.ts during emit)
+/home/src/projects/project1/file2.ts (computed .d.ts during emit)
+/home/src/projects/project1/index.ts (computed .d.ts during emit)
+/home/src/projects/project1/utils.d.ts (used version)
+
+
+//// [/home/src/projects/project1/file.d.ts]
+export declare const file = 10;
+
+
+//// [/home/src/projects/project1/file.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.file = void 0;
+exports.file = 10;
+
+
+//// [/home/src/projects/project1/file2.d.ts]
+
+
+//// [/home/src/projects/project1/file2.js]
+/// <reference lib="webworker2"/>
+/// <reference lib="unknownlib"/>
+/// <reference lib="scripthost"/>
+
+
+//// [/home/src/projects/project1/index.d.ts]
+export declare const x = "type1";
+
+
+//// [/home/src/projects/project1/index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.x = void 0;
+exports.x = "type1";
+
+
+//// [/home/src/projects/project1/tsconfig.tsbuildinfo]
+{"program":{"fileNames":["../../lib/lib.d.ts","../../lib/lib.scripthost.d.ts","./core.d.ts","./file.ts","./file2.ts","./index.ts","./utils.d.ts"],"fileInfos":[{"version":"3858781397-/// <reference no-default-lib=\"true\"/>\ninterface Boolean {}\ninterface Function {}\ninterface CallableFunction {}\ninterface NewableFunction {}\ninterface IArguments {}\ninterface Number { toExponential: any; }\ninterface Object {}\ninterface RegExp {}\ninterface String { charAt: any; }\ninterface Array<T> { length: number; [n: number]: T; }\ninterface ReadonlyArray<T> {}\ndeclare const console: { log(msg: any): void; };","affectsGlobalScope":true,"impliedFormat":1},{"version":"-5403980302-interface ScriptHostInterface { }","affectsGlobalScope":true,"impliedFormat":1},{"version":"-15683237936-export const core = 10;","impliedFormat":1},{"version":"-16628394009-export const file = 10;","signature":"-9025507999-export declare const file = 10;\n","impliedFormat":1},{"version":"-15920922626-/// <reference lib=\"webworker2\"/>\n/// <reference lib=\"unknownlib\"/>\n/// <reference lib=\"scripthost\"/>\n","signature":"5381-","impliedFormat":1},{"version":"-11532698187-export const x = \"type1\";","signature":"-5899226897-export declare const x = \"type1\";\n","impliedFormat":1},{"version":"-13729955264-export const y = 10;","impliedFormat":1}],"root":[[3,7]],"options":{"composite":true},"referencedMap":[],"semanticDiagnosticsPerFile":[1,2,3,4,5,6,7],"latestChangedDtsFile":"./index.d.ts"},"version":"FakeTSVersion"}
+
+//// [/home/src/projects/project1/tsconfig.tsbuildinfo.readable.baseline.txt]
+{
+  "program": {
+    "fileNames": [
+      "../../lib/lib.d.ts",
+      "../../lib/lib.scripthost.d.ts",
+      "./core.d.ts",
+      "./file.ts",
+      "./file2.ts",
+      "./index.ts",
+      "./utils.d.ts"
+    ],
+    "fileInfos": {
+      "../../lib/lib.d.ts": {
+        "original": {
+          "version": "3858781397-/// <reference no-default-lib=\"true\"/>\ninterface Boolean {}\ninterface Function {}\ninterface CallableFunction {}\ninterface NewableFunction {}\ninterface IArguments {}\ninterface Number { toExponential: any; }\ninterface Object {}\ninterface RegExp {}\ninterface String { charAt: any; }\ninterface Array<T> { length: number; [n: number]: T; }\ninterface ReadonlyArray<T> {}\ndeclare const console: { log(msg: any): void; };",
+          "affectsGlobalScope": true,
+          "impliedFormat": 1
+        },
+        "version": "3858781397-/// <reference no-default-lib=\"true\"/>\ninterface Boolean {}\ninterface Function {}\ninterface CallableFunction {}\ninterface NewableFunction {}\ninterface IArguments {}\ninterface Number { toExponential: any; }\ninterface Object {}\ninterface RegExp {}\ninterface String { charAt: any; }\ninterface Array<T> { length: number; [n: number]: T; }\ninterface ReadonlyArray<T> {}\ndeclare const console: { log(msg: any): void; };",
+        "signature": "3858781397-/// <reference no-default-lib=\"true\"/>\ninterface Boolean {}\ninterface Function {}\ninterface CallableFunction {}\ninterface NewableFunction {}\ninterface IArguments {}\ninterface Number { toExponential: any; }\ninterface Object {}\ninterface RegExp {}\ninterface String { charAt: any; }\ninterface Array<T> { length: number; [n: number]: T; }\ninterface ReadonlyArray<T> {}\ndeclare const console: { log(msg: any): void; };",
+        "affectsGlobalScope": true,
+        "impliedFormat": "commonjs"
+      },
+      "../../lib/lib.scripthost.d.ts": {
+        "original": {
+          "version": "-5403980302-interface ScriptHostInterface { }",
+          "affectsGlobalScope": true,
+          "impliedFormat": 1
+        },
+        "version": "-5403980302-interface ScriptHostInterface { }",
+        "signature": "-5403980302-interface ScriptHostInterface { }",
+        "affectsGlobalScope": true,
+        "impliedFormat": "commonjs"
+      },
+      "./core.d.ts": {
+        "original": {
+          "version": "-15683237936-export const core = 10;",
+          "impliedFormat": 1
+        },
+        "version": "-15683237936-export const core = 10;",
+        "signature": "-15683237936-export const core = 10;",
+        "impliedFormat": "commonjs"
+      },
+      "./file.ts": {
+        "original": {
+          "version": "-16628394009-export const file = 10;",
+          "signature": "-9025507999-export declare const file = 10;\n",
+          "impliedFormat": 1
+        },
+        "version": "-16628394009-export const file = 10;",
+        "signature": "-9025507999-export declare const file = 10;\n",
+        "impliedFormat": "commonjs"
+      },
+      "./file2.ts": {
+        "original": {
+          "version": "-15920922626-/// <reference lib=\"webworker2\"/>\n/// <reference lib=\"unknownlib\"/>\n/// <reference lib=\"scripthost\"/>\n",
+          "signature": "5381-",
+          "impliedFormat": 1
+        },
+        "version": "-15920922626-/// <reference lib=\"webworker2\"/>\n/// <reference lib=\"unknownlib\"/>\n/// <reference lib=\"scripthost\"/>\n",
+        "signature": "5381-",
+        "impliedFormat": "commonjs"
+      },
+      "./index.ts": {
+        "original": {
+          "version": "-11532698187-export const x = \"type1\";",
+          "signature": "-5899226897-export declare const x = \"type1\";\n",
+          "impliedFormat": 1
+        },
+        "version": "-11532698187-export const x = \"type1\";",
+        "signature": "-5899226897-export declare const x = \"type1\";\n",
+        "impliedFormat": "commonjs"
+      },
+      "./utils.d.ts": {
+        "original": {
+          "version": "-13729955264-export const y = 10;",
+          "impliedFormat": 1
+        },
+        "version": "-13729955264-export const y = 10;",
+        "signature": "-13729955264-export const y = 10;",
+        "impliedFormat": "commonjs"
+      }
+    },
+    "root": [
+      [
+        [
+          3,
+          7
+        ],
+        [
+          "./core.d.ts",
+          "./file.ts",
+          "./file2.ts",
+          "./index.ts",
+          "./utils.d.ts"
+        ]
+      ]
+    ],
+    "options": {
+      "composite": true
+    },
+    "referencedMap": {},
+    "semanticDiagnosticsPerFile": [
+      "../../lib/lib.d.ts",
+      "../../lib/lib.scripthost.d.ts",
+      "./core.d.ts",
+      "./file.ts",
+      "./file2.ts",
+      "./index.ts",
+      "./utils.d.ts"
+    ],
+    "latestChangedDtsFile": "./index.d.ts"
+  },
+  "version": "FakeTSVersion",
+  "size": 1512
+}
+

tests/baselines/reference/tscWatch/forceConsistentCasingInFileNames/when-file-is-included-from-multiple-places-with-different-casing.js

@@ -0,0 +1,975 @@
+currentDirectory:: /home/src/projects/project useCaseSensitiveFileNames: false
+Input::
+//// [/home/src/projects/project/src/struct.d.ts]
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+
+//// [/home/src/projects/project/src/anotherFile.ts]
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+
+//// [/home/src/projects/project/src/oneMore.ts]
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+
+
+//// [/home/src/projects/project/tsconfig.json]
+{}
+
+//// [/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts]
+export function foo(): void
+
+//// [/a/lib/lib.d.ts]
+/// <reference no-default-lib="true"/>
+interface Boolean {}
+interface Function {}
+interface CallableFunction {}
+interface NewableFunction {}
+interface IArguments {}
+interface Number { toExponential: any; }
+interface Object {}
+interface RegExp {}
+interface String { charAt: any; }
+interface Array<T> { length: number; [n: number]: T; }
+interface ReadonlyArray<T> {}
+declare const console: { log(msg: any): void; };
+
+
+/a/lib/tsc.js -w --explainFiles
+Output::
+>> Screen clear
+[HH:MM:SS AM] Starting compilation in watch mode...
+
+src/anotherFile.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+src/anotherFile.ts:3:22 - error TS1261: Already included file name '/home/src/projects/project/src/Struct.d.ts' differs from file name '/home/src/projects/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+3 import * as xs3 from "./Struct";
+                       ~~~~~~~~~~
+
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/anotherFile.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/oneMore.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+src/oneMore.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/Struct.d.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+src/Struct.d.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+../../../../a/lib/lib.d.ts
+  Default library for target 'es5'
+node_modules/fp-ts/lib/Struct.d.ts
+  Imported via "fp-ts/lib/Struct" from file 'src/anotherFile.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/anotherFile.ts'
+  Imported via "fp-ts/lib/Struct" from file 'src/Struct.d.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/Struct.d.ts'
+  Imported via "fp-ts/lib/Struct" from file 'src/oneMore.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/oneMore.ts'
+src/Struct.d.ts
+  Imported via "./Struct" from file 'src/anotherFile.ts'
+  Imported via "./Struct" from file 'src/Struct.d.ts'
+  Imported via "./struct" from file 'src/Struct.d.ts'
+  Imported via "./struct" from file 'src/anotherFile.ts'
+  Imported via "./Struct" from file 'src/oneMore.ts'
+  Imported via "./struct" from file 'src/oneMore.ts'
+  Matched by default include pattern '**/*'
+src/anotherFile.ts
+  Matched by default include pattern '**/*'
+src/oneMore.ts
+  Matched by default include pattern '**/*'
+[HH:MM:SS AM] Found 7 errors. Watching for file changes.
+
+
+
+//// [/home/src/projects/project/src/anotherFile.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+
+
+//// [/home/src/projects/project/src/oneMore.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+
+
+
+PolledWatches::
+/home/src/projects/node_modules/@types: *new*
+  {"pollingInterval":500}
+/home/src/projects/package.json: *new*
+  {"pollingInterval":2000}
+/home/src/projects/project/node_modules/@types: *new*
+  {"pollingInterval":500}
+/home/src/projects/project/node_modules/fp-ts/lib/package.json: *new*
+  {"pollingInterval":2000}
+/home/src/projects/project/node_modules/fp-ts/package.json: *new*
+  {"pollingInterval":2000}
+/home/src/projects/project/node_modules/package.json: *new*
+  {"pollingInterval":2000}
+/home/src/projects/project/package.json: *new*
+  {"pollingInterval":2000}
+/home/src/projects/project/src/package.json: *new*
+  {"pollingInterval":2000}
+
+FsWatches::
+/a/lib/lib.d.ts: *new*
+  {}
+/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts: *new*
+  {}
+/home/src/projects/project/src/Struct.d.ts: *new*
+  {}
+/home/src/projects/project/src/anotherFile.ts: *new*
+  {}
+/home/src/projects/project/src/oneMore.ts: *new*
+  {}
+/home/src/projects/project/tsconfig.json: *new*
+  {}
+
+FsWatchesRecursive::
+/home/src/projects/project: *new*
+  {}
+/home/src/projects/project/node_modules: *new*
+  {}
+/home/src/projects/project/src: *new*
+  {}
+
+Program root files: [
+  "/home/src/projects/project/src/anotherFile.ts",
+  "/home/src/projects/project/src/oneMore.ts",
+  "/home/src/projects/project/src/struct.d.ts"
+]
+Program options: {
+  "watch": true,
+  "explainFiles": true,
+  "configFilePath": "/home/src/projects/project/tsconfig.json"
+}
+Program structureReused: Not
+Program files::
+/a/lib/lib.d.ts
+/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts
+/home/src/projects/project/src/Struct.d.ts
+/home/src/projects/project/src/anotherFile.ts
+/home/src/projects/project/src/oneMore.ts
+
+Semantic diagnostics in builder refreshed for::
+/a/lib/lib.d.ts
+/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts
+/home/src/projects/project/src/Struct.d.ts
+/home/src/projects/project/src/anotherFile.ts
+/home/src/projects/project/src/oneMore.ts
+
+Shape signatures in builder refreshed for::
+/a/lib/lib.d.ts (used version)
+/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts (used version)
+/home/src/projects/project/src/struct.d.ts (used version)
+/home/src/projects/project/src/anotherfile.ts (used version)
+/home/src/projects/project/src/onemore.ts (used version)
+
+exitCode:: ExitStatus.undefined
+
+Change:: change to reuse imports
+
+Input::
+//// [/home/src/projects/project/src/struct.d.ts]
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+import * as xs4 from "./struct";
+export const y = 10;
+
+
+Timeout callback:: count: 1
+1: timerToUpdateProgram *new*
+
+Before running Timeout callback:: count: 1
+1: timerToUpdateProgram
+
+After running Timeout callback:: count: 0
+Output::
+>> Screen clear
+[HH:MM:SS AM] File change detected. Starting incremental compilation...
+
+src/anotherFile.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+src/anotherFile.ts:3:22 - error TS1261: Already included file name '/home/src/projects/project/src/Struct.d.ts' differs from file name '/home/src/projects/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+3 import * as xs3 from "./Struct";
+                       ~~~~~~~~~~
+
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/anotherFile.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/oneMore.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+src/oneMore.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/Struct.d.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+src/Struct.d.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+../../../../a/lib/lib.d.ts
+  Default library for target 'es5'
+node_modules/fp-ts/lib/Struct.d.ts
+  Imported via "fp-ts/lib/Struct" from file 'src/anotherFile.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/anotherFile.ts'
+  Imported via "fp-ts/lib/Struct" from file 'src/Struct.d.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/Struct.d.ts'
+  Imported via "fp-ts/lib/Struct" from file 'src/oneMore.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/oneMore.ts'
+src/Struct.d.ts
+  Imported via "./Struct" from file 'src/anotherFile.ts'
+  Imported via "./Struct" from file 'src/Struct.d.ts'
+  Imported via "./struct" from file 'src/Struct.d.ts'
+  Imported via "./struct" from file 'src/anotherFile.ts'
+  Imported via "./Struct" from file 'src/oneMore.ts'
+  Imported via "./struct" from file 'src/oneMore.ts'
+  Matched by default include pattern '**/*'
+src/anotherFile.ts
+  Matched by default include pattern '**/*'
+src/oneMore.ts
+  Matched by default include pattern '**/*'
+[HH:MM:SS AM] Found 7 errors. Watching for file changes.
+
+
+
+//// [/home/src/projects/project/src/anotherFile.js] file written with same contents
+//// [/home/src/projects/project/src/oneMore.js] file written with same contents
+
+
+Program root files: [
+  "/home/src/projects/project/src/anotherFile.ts",
+  "/home/src/projects/project/src/oneMore.ts",
+  "/home/src/projects/project/src/struct.d.ts"
+]
+Program options: {
+  "watch": true,
+  "explainFiles": true,
+  "configFilePath": "/home/src/projects/project/tsconfig.json"
+}
+Program structureReused: Completely
+Program files::
+/a/lib/lib.d.ts
+/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts
+/home/src/projects/project/src/Struct.d.ts
+/home/src/projects/project/src/anotherFile.ts
+/home/src/projects/project/src/oneMore.ts
+
+Semantic diagnostics in builder refreshed for::
+/home/src/projects/project/src/Struct.d.ts
+/home/src/projects/project/src/anotherFile.ts
+/home/src/projects/project/src/oneMore.ts
+
+Shape signatures in builder refreshed for::
+/home/src/projects/project/src/struct.d.ts (used version)
+/home/src/projects/project/src/onemore.ts (computed .d.ts)
+/home/src/projects/project/src/anotherfile.ts (computed .d.ts)
+
+exitCode:: ExitStatus.undefined
+
+Change:: change to update imports
+
+Input::
+//// [/home/src/projects/project/src/struct.d.ts]
+import * as xs1 from "fp-ts/lib/Struct";
+import * as xs2 from "fp-ts/lib/struct";
+import * as xs3 from "./Struct";
+
+
+
+Timeout callback:: count: 1
+2: timerToUpdateProgram *new*
+
+Before running Timeout callback:: count: 1
+2: timerToUpdateProgram
+
+After running Timeout callback:: count: 0
+Output::
+>> Screen clear
+[HH:MM:SS AM] File change detected. Starting incremental compilation...
+
+src/anotherFile.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+src/anotherFile.ts:3:22 - error TS1261: Already included file name '/home/src/projects/project/src/Struct.d.ts' differs from file name '/home/src/projects/project/src/struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+3 import * as xs3 from "./Struct";
+                       ~~~~~~~~~~
+
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/anotherFile.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/oneMore.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+src/oneMore.ts:4:22 - error TS1149: File name '/home/src/projects/project/src/struct.d.ts' differs from already included file name '/home/src/projects/project/src/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "./Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "./Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "./struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Matched by default include pattern '**/*'
+
+4 import * as xs4 from "./struct";
+                       ~~~~~~~~~~
+
+  src/anotherFile.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:4:22
+    4 import * as xs4 from "./struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:3:22
+    3 import * as xs3 from "./Struct";
+                           ~~~~~~~~~~
+    File is included via import here.
+
+src/Struct.d.ts:2:22 - error TS1149: File name '/home/src/projects/project/node_modules/fp-ts/lib/struct.d.ts' differs from already included file name '/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts' only in casing.
+  The file is in the program because:
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/anotherFile.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/Struct.d.ts'
+    Imported via "fp-ts/lib/Struct" from file '/home/src/projects/project/src/oneMore.ts'
+    Imported via "fp-ts/lib/struct" from file '/home/src/projects/project/src/oneMore.ts'
+
+2 import * as xs2 from "fp-ts/lib/struct";
+                       ~~~~~~~~~~~~~~~~~~
+
+  src/anotherFile.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/anotherFile.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/Struct.d.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:1:22
+    1 import * as xs1 from "fp-ts/lib/Struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+  src/oneMore.ts:2:22
+    2 import * as xs2 from "fp-ts/lib/struct";
+                           ~~~~~~~~~~~~~~~~~~
+    File is included via import here.
+
+../../../../a/lib/lib.d.ts
+  Default library for target 'es5'
+node_modules/fp-ts/lib/Struct.d.ts
+  Imported via "fp-ts/lib/Struct" from file 'src/anotherFile.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/anotherFile.ts'
+  Imported via "fp-ts/lib/Struct" from file 'src/Struct.d.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/Struct.d.ts'
+  Imported via "fp-ts/lib/Struct" from file 'src/oneMore.ts'
+  Imported via "fp-ts/lib/struct" from file 'src/oneMore.ts'
+src/Struct.d.ts
+  Imported via "./Struct" from file 'src/anotherFile.ts'
+  Imported via "./Struct" from file 'src/Struct.d.ts'
+  Imported via "./struct" from file 'src/anotherFile.ts'
+  Imported via "./Struct" from file 'src/oneMore.ts'
+  Imported via "./struct" from file 'src/oneMore.ts'
+  Matched by default include pattern '**/*'
+src/anotherFile.ts
+  Matched by default include pattern '**/*'
+src/oneMore.ts
+  Matched by default include pattern '**/*'
+[HH:MM:SS AM] Found 6 errors. Watching for file changes.
+
+
+
+//// [/home/src/projects/project/src/anotherFile.js] file written with same contents
+//// [/home/src/projects/project/src/oneMore.js] file written with same contents
+
+
+Program root files: [
+  "/home/src/projects/project/src/anotherFile.ts",
+  "/home/src/projects/project/src/oneMore.ts",
+  "/home/src/projects/project/src/struct.d.ts"
+]
+Program options: {
+  "watch": true,
+  "explainFiles": true,
+  "configFilePath": "/home/src/projects/project/tsconfig.json"
+}
+Program structureReused: SafeModules
+Program files::
+/a/lib/lib.d.ts
+/home/src/projects/project/node_modules/fp-ts/lib/Struct.d.ts
+/home/src/projects/project/src/Struct.d.ts
+/home/src/projects/project/src/anotherFile.ts
+/home/src/projects/project/src/oneMore.ts
+
+Semantic diagnostics in builder refreshed for::
+/home/src/projects/project/src/Struct.d.ts
+/home/src/projects/project/src/anotherFile.ts
+/home/src/projects/project/src/oneMore.ts
+
+Shape signatures in builder refreshed for::
+/home/src/projects/project/src/struct.d.ts (used version)
+/home/src/projects/project/src/onemore.ts (computed .d.ts)
+/home/src/projects/project/src/anotherfile.ts (computed .d.ts)
+
+exitCode:: ExitStatus.undefined

tests/baselines/reference/tsserver/watchEnvironment/external-project-watch-options-errors.js

@@ -79,7 +79,6 @@ Info seq  [hh:mm:ss:mss] 	Files (4)
 	../../../../a/lib/lib.d.ts
 	  Default library for target 'es5'
 	node_modules/bar/foo.d.ts
-	  Imported via "./foo" from file 'node_modules/bar/index.d.ts'
 	  Imported via "./foo" from file 'node_modules/bar/index.d.ts'
 	  Root file specified for compilation
 	node_modules/bar/index.d.ts

tests/baselines/reference/tsserver/watchEnvironment/external-project-watch-options-in-host-configuration.js

@@ -106,7 +106,6 @@ Info seq  [hh:mm:ss:mss] 	Files (4)
 	../../../../a/lib/lib.d.ts
 	  Default library for target 'es5'
 	node_modules/bar/foo.d.ts
-	  Imported via "./foo" from file 'node_modules/bar/index.d.ts'
 	  Imported via "./foo" from file 'node_modules/bar/index.d.ts'
 	  Root file specified for compilation
 	node_modules/bar/index.d.ts

tests/baselines/reference/tsserver/watchEnvironment/external-project-watch-options.js

@@ -77,7 +77,6 @@ Info seq  [hh:mm:ss:mss] 	Files (4)
 	../../../../a/lib/lib.d.ts
 	  Default library for target 'es5'
 	node_modules/bar/foo.d.ts
-	  Imported via "./foo" from file 'node_modules/bar/index.d.ts'
 	  Imported via "./foo" from file 'node_modules/bar/index.d.ts'
 	  Root file specified for compilation
 	node_modules/bar/index.d.ts