Add new option "noUncheckedSideEffectImports" (#58941)

src/compiler/checker.ts

@@ -720,6 +720,7 @@ import {
     isSetAccessorDeclaration,
     isShorthandAmbientModuleSymbol,
     isShorthandPropertyAssignment,
+    isSideEffectImport,
     isSingleOrDoubleQuote,
     isSourceFile,
     isSourceFileJS,
@@ -1505,6 +1506,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     var noImplicitThis = getStrictOptionValue(compilerOptions, "noImplicitThis");
     var useUnknownInCatchVariables = getStrictOptionValue(compilerOptions, "useUnknownInCatchVariables");
     var exactOptionalPropertyTypes = compilerOptions.exactOptionalPropertyTypes;
+    var noUncheckedSideEffectImports = !!compilerOptions.noUncheckedSideEffectImports;
 
     var checkBinaryExpression = createCheckBinaryExpression();
     var emitResolver = createResolver();
@@ -4660,7 +4662,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 // merged symbol is module declaration symbol combined with all augmentations
                 return getMergedSymbol(sourceFile.symbol);
             }
-            if (errorNode && moduleNotFoundError) {
+            if (errorNode && moduleNotFoundError && !isSideEffectImport(errorNode)) {
                 // report errors only if it was requested
                 error(errorNode, Diagnostics.File_0_is_not_a_module, sourceFile.fileName);
             }
@@ -4765,6 +4767,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function errorOnImplicitAnyModule(isError: boolean, errorNode: Node, sourceFile: SourceFile, mode: ResolutionMode, { packageId, resolvedFileName }: ResolvedModuleFull, moduleReference: string): void {
+        if (isSideEffectImport(errorNode)) {
+            return;
+        }
+
         let errorInfo: DiagnosticMessageChain | undefined;
         if (!isExternalModuleNameRelative(moduleReference) && packageId) {
             errorInfo = createModuleNotFoundChain(sourceFile, host, moduleReference, mode, packageId.name);
@@ -47246,6 +47252,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     }
                 }
             }
+            else if (noUncheckedSideEffectImports && !importClause) {
+                void resolveExternalModuleName(node, node.moduleSpecifier);
+            }
         }
         checkImportAttributes(node);
     }

src/compiler/commandLineParser.ts

@@ -1202,6 +1202,15 @@ const commandOptionsWithoutBuild: CommandLineOption[] = [
         category: Diagnostics.Modules,
         description: Diagnostics.Conditions_to_set_in_addition_to_the_resolver_specific_defaults_when_resolving_imports,
     },
+    {
+        name: "noUncheckedSideEffectImports",
+        type: "boolean",
+        affectsSemanticDiagnostics: true,
+        affectsBuildInfo: true,
+        category: Diagnostics.Modules,
+        description: Diagnostics.Check_side_effect_imports,
+        defaultValueDescription: false,
+    },
 
     // Source Maps
     {

src/compiler/diagnosticMessages.json

@@ -6388,6 +6388,10 @@
         "category": "Message",
         "code": 6805
     },
+    "Check side effect imports.": {
+        "category": "Message",
+        "code": 6806
+    },
 
     "one of:": {
         "category": "Message",

src/compiler/types.ts

@@ -7418,6 +7418,7 @@ export interface CompilerOptions {
     target?: ScriptTarget;
     traceResolution?: boolean;
     useUnknownInCatchVariables?: boolean;
+    noUncheckedSideEffectImports?: boolean;
     resolveJsonModule?: boolean;
     types?: string[];
     /** Paths used to compute primary types search locations */

src/compiler/utilities.ts

@@ -287,6 +287,7 @@ import {
     isIdentifier,
     isIdentifierStart,
     isIdentifierText,
+    isImportDeclaration,
     isImportTypeNode,
     isInterfaceDeclaration,
     isJSDoc,
@@ -11758,3 +11759,9 @@ export function hasInferredType(node: Node): node is HasInferredType {
             return false;
     }
 }
+
+/** @internal */
+export function isSideEffectImport(node: Node): boolean {
+    const ancestor = findAncestor(node, isImportDeclaration);
+    return !!ancestor && !ancestor.importClause;
+}

src/testRunner/unittests/tscWatch/programUpdates.ts

@@ -2245,4 +2245,40 @@ import { x } from "../b";`,
             },
         ],
     });
+
+    verifyTscWatch({
+        scenario,
+        subScenario: "when changing noUncheckedSideEffectImports of config file",
+        commandLineArgs: ["-w", "-p", ".", "--extendedDiagnostics"],
+        sys: () => {
+            const module1: File = {
+                path: `/user/username/projects/myproject/a.ts`,
+                content: `import "does-not-exist";`,
+            };
+            const config: File = {
+                path: `/user/username/projects/myproject/tsconfig.json`,
+                content: jsonToReadableText({
+                    compilerOptions: {
+                        noUncheckedSideEffectImports: false,
+                    },
+                }),
+            };
+            return createWatchedSystem([module1, config, libFile], { currentDirectory: "/user/username/projects/myproject" });
+        },
+        edits: [
+            {
+                caption: "Change noUncheckedSideEffectImports to true",
+                edit: sys =>
+                    sys.writeFile(
+                        `/user/username/projects/myproject/tsconfig.json`,
+                        jsonToReadableText({
+                            compilerOptions: {
+                                noUncheckedSideEffectImports: true,
+                            },
+                        }),
+                    ),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+        ],
+    });
 });

tests/baselines/reference/api/typescript.d.ts

@@ -7017,6 +7017,7 @@ declare namespace ts {
         target?: ScriptTarget;
         traceResolution?: boolean;
         useUnknownInCatchVariables?: boolean;
+        noUncheckedSideEffectImports?: boolean;
         resolveJsonModule?: boolean;
         types?: string[];
         /** Paths used to compute primary types search locations */

tests/baselines/reference/config/initTSConfig/Default initialized TSConfig/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with --help/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with --watch/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with advanced options/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with boolean value compiler options/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with enum value compiler options/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with files options/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with incorrect compiler option value/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with incorrect compiler option/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with list compiler options with enum value/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/initTSConfig/Initialized TSConfig with list compiler options/tsconfig.json

@@ -39,6 +39,7 @@
     // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
     // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
     // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
     // "resolveJsonModule": true,                        /* Enable importing .json files. */
     // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
     // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */

tests/baselines/reference/config/showConfig/Shows tsconfig for single option/noUncheckedSideEffectImports/tsconfig.json

@@ -0,0 +1,5 @@
+{
+    "compilerOptions": {
+        "noUncheckedSideEffectImports": true
+    }
+}

tests/baselines/reference/sideEffectImports1(module=commonjs,nouncheckedsideeffectimports=false).js

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+//// [sideEffectImports1.ts]
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+
+
+//// [sideEffectImports1.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("does-not-exist");
+require("./does-not-exist-either");
+require("./does-not-exist-either.js");

tests/baselines/reference/sideEffectImports1(module=commonjs,nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=commonjs,nouncheckedsideeffectimports=false).types

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=commonjs,nouncheckedsideeffectimports=true).errors.txt

@@ -0,0 +1,16 @@
+sideEffectImports1.ts(1,8): error TS2307: Cannot find module 'does-not-exist' or its corresponding type declarations.
+sideEffectImports1.ts(2,8): error TS2307: Cannot find module './does-not-exist-either' or its corresponding type declarations.
+sideEffectImports1.ts(3,8): error TS2307: Cannot find module './does-not-exist-either.js' or its corresponding type declarations.
+
+
+==== sideEffectImports1.ts (3 errors) ====
+    import "does-not-exist";
+           ~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module 'does-not-exist' or its corresponding type declarations.
+    import "./does-not-exist-either";
+           ~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './does-not-exist-either' or its corresponding type declarations.
+    import "./does-not-exist-either.js";
+           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './does-not-exist-either.js' or its corresponding type declarations.
+    

tests/baselines/reference/sideEffectImports1(module=commonjs,nouncheckedsideeffectimports=true).js

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+//// [sideEffectImports1.ts]
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+
+
+//// [sideEffectImports1.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("does-not-exist");
+require("./does-not-exist-either");
+require("./does-not-exist-either.js");

tests/baselines/reference/sideEffectImports1(module=commonjs,nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=commonjs,nouncheckedsideeffectimports=true).types

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=nodenext,nouncheckedsideeffectimports=false).js

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+//// [sideEffectImports1.ts]
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+
+
+//// [sideEffectImports1.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("does-not-exist");
+require("./does-not-exist-either");
+require("./does-not-exist-either.js");

tests/baselines/reference/sideEffectImports1(module=nodenext,nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=nodenext,nouncheckedsideeffectimports=false).types

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=nodenext,nouncheckedsideeffectimports=true).errors.txt

@@ -0,0 +1,16 @@
+sideEffectImports1.ts(1,8): error TS2307: Cannot find module 'does-not-exist' or its corresponding type declarations.
+sideEffectImports1.ts(2,8): error TS2307: Cannot find module './does-not-exist-either' or its corresponding type declarations.
+sideEffectImports1.ts(3,8): error TS2307: Cannot find module './does-not-exist-either.js' or its corresponding type declarations.
+
+
+==== sideEffectImports1.ts (3 errors) ====
+    import "does-not-exist";
+           ~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module 'does-not-exist' or its corresponding type declarations.
+    import "./does-not-exist-either";
+           ~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './does-not-exist-either' or its corresponding type declarations.
+    import "./does-not-exist-either.js";
+           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './does-not-exist-either.js' or its corresponding type declarations.
+    

tests/baselines/reference/sideEffectImports1(module=nodenext,nouncheckedsideeffectimports=true).js

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+//// [sideEffectImports1.ts]
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+
+
+//// [sideEffectImports1.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("does-not-exist");
+require("./does-not-exist-either");
+require("./does-not-exist-either.js");

tests/baselines/reference/sideEffectImports1(module=nodenext,nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=nodenext,nouncheckedsideeffectimports=true).types

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=preserve,nouncheckedsideeffectimports=false).js

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+//// [sideEffectImports1.ts]
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+
+
+//// [sideEffectImports1.js]
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";

tests/baselines/reference/sideEffectImports1(module=preserve,nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=preserve,nouncheckedsideeffectimports=false).types

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=preserve,nouncheckedsideeffectimports=true).errors.txt

@@ -0,0 +1,16 @@
+sideEffectImports1.ts(1,8): error TS2307: Cannot find module 'does-not-exist' or its corresponding type declarations.
+sideEffectImports1.ts(2,8): error TS2307: Cannot find module './does-not-exist-either' or its corresponding type declarations.
+sideEffectImports1.ts(3,8): error TS2307: Cannot find module './does-not-exist-either.js' or its corresponding type declarations.
+
+
+==== sideEffectImports1.ts (3 errors) ====
+    import "does-not-exist";
+           ~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module 'does-not-exist' or its corresponding type declarations.
+    import "./does-not-exist-either";
+           ~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './does-not-exist-either' or its corresponding type declarations.
+    import "./does-not-exist-either.js";
+           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './does-not-exist-either.js' or its corresponding type declarations.
+    

tests/baselines/reference/sideEffectImports1(module=preserve,nouncheckedsideeffectimports=true).js

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+//// [sideEffectImports1.ts]
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+
+
+//// [sideEffectImports1.js]
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";

tests/baselines/reference/sideEffectImports1(module=preserve,nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports1(module=preserve,nouncheckedsideeffectimports=true).types

@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/sideEffectImports1.ts] ////
+
+=== sideEffectImports1.ts ===
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";
+

tests/baselines/reference/sideEffectImports2(noimplicitany=false,nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports2.ts] ////
+
+=== index.ts ===
+
+import "source-map-support/register";
+

tests/baselines/reference/sideEffectImports2(noimplicitany=false,nouncheckedsideeffectimports=false).types

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports2.ts] ////
+
+=== index.ts ===
+
+import "source-map-support/register";
+

tests/baselines/reference/sideEffectImports2(noimplicitany=false,nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports2.ts] ////
+
+=== index.ts ===
+
+import "source-map-support/register";
+

tests/baselines/reference/sideEffectImports2(noimplicitany=false,nouncheckedsideeffectimports=true).types

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports2.ts] ////
+
+=== index.ts ===
+
+import "source-map-support/register";
+

tests/baselines/reference/sideEffectImports2(noimplicitany=true,nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports2.ts] ////
+
+=== index.ts ===
+
+import "source-map-support/register";
+

tests/baselines/reference/sideEffectImports2(noimplicitany=true,nouncheckedsideeffectimports=false).types

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports2.ts] ////
+
+=== index.ts ===
+
+import "source-map-support/register";
+

tests/baselines/reference/sideEffectImports2(noimplicitany=true,nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports2.ts] ////
+
+=== index.ts ===
+
+import "source-map-support/register";
+

tests/baselines/reference/sideEffectImports2(noimplicitany=true,nouncheckedsideeffectimports=true).types

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports2.ts] ////
+
+=== index.ts ===
+
+import "source-map-support/register";
+

tests/baselines/reference/sideEffectImports3(moduledetection=auto,nouncheckedsideeffectimports=false).js

@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+//// [index.ts]
+import "./not-a-module";
+
+//// [not-a-module.ts]
+console.log("Hello, world!");
+
+
+//// [not-a-module.js]
+console.log("Hello, world!");
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("./not-a-module");

tests/baselines/reference/sideEffectImports3(moduledetection=auto,nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+

tests/baselines/reference/sideEffectImports3(moduledetection=auto,nouncheckedsideeffectimports=false).types

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log("Hello, world!") : void
+>                             : ^^^^
+>console.log : (...data: any[]) => void
+>            : ^^^^    ^^     ^^^^^    
+>console : Console
+>        : ^^^^^^^
+>log : (...data: any[]) => void
+>    : ^^^^    ^^     ^^^^^    
+>"Hello, world!" : "Hello, world!"
+>                : ^^^^^^^^^^^^^^^
+

tests/baselines/reference/sideEffectImports3(moduledetection=auto,nouncheckedsideeffectimports=true).js

@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+//// [index.ts]
+import "./not-a-module";
+
+//// [not-a-module.ts]
+console.log("Hello, world!");
+
+
+//// [not-a-module.js]
+console.log("Hello, world!");
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("./not-a-module");

tests/baselines/reference/sideEffectImports3(moduledetection=auto,nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+

tests/baselines/reference/sideEffectImports3(moduledetection=auto,nouncheckedsideeffectimports=true).types

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log("Hello, world!") : void
+>                             : ^^^^
+>console.log : (...data: any[]) => void
+>            : ^^^^    ^^     ^^^^^    
+>console : Console
+>        : ^^^^^^^
+>log : (...data: any[]) => void
+>    : ^^^^    ^^     ^^^^^    
+>"Hello, world!" : "Hello, world!"
+>                : ^^^^^^^^^^^^^^^
+

tests/baselines/reference/sideEffectImports3(moduledetection=force,nouncheckedsideeffectimports=false).js

@@ -0,0 +1,17 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+//// [index.ts]
+import "./not-a-module";
+
+//// [not-a-module.ts]
+console.log("Hello, world!");
+
+
+//// [not-a-module.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+console.log("Hello, world!");
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("./not-a-module");

tests/baselines/reference/sideEffectImports3(moduledetection=force,nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+

tests/baselines/reference/sideEffectImports3(moduledetection=force,nouncheckedsideeffectimports=false).types

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log("Hello, world!") : void
+>                             : ^^^^
+>console.log : (...data: any[]) => void
+>            : ^^^^    ^^     ^^^^^    
+>console : Console
+>        : ^^^^^^^
+>log : (...data: any[]) => void
+>    : ^^^^    ^^     ^^^^^    
+>"Hello, world!" : "Hello, world!"
+>                : ^^^^^^^^^^^^^^^
+

tests/baselines/reference/sideEffectImports3(moduledetection=force,nouncheckedsideeffectimports=true).js

@@ -0,0 +1,17 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+//// [index.ts]
+import "./not-a-module";
+
+//// [not-a-module.ts]
+console.log("Hello, world!");
+
+
+//// [not-a-module.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+console.log("Hello, world!");
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("./not-a-module");

tests/baselines/reference/sideEffectImports3(moduledetection=force,nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+

tests/baselines/reference/sideEffectImports3(moduledetection=force,nouncheckedsideeffectimports=true).types

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log("Hello, world!") : void
+>                             : ^^^^
+>console.log : (...data: any[]) => void
+>            : ^^^^    ^^     ^^^^^    
+>console : Console
+>        : ^^^^^^^
+>log : (...data: any[]) => void
+>    : ^^^^    ^^     ^^^^^    
+>"Hello, world!" : "Hello, world!"
+>                : ^^^^^^^^^^^^^^^
+

tests/baselines/reference/sideEffectImports3(moduledetection=legacy,nouncheckedsideeffectimports=false).js

@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+//// [index.ts]
+import "./not-a-module";
+
+//// [not-a-module.ts]
+console.log("Hello, world!");
+
+
+//// [not-a-module.js]
+console.log("Hello, world!");
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("./not-a-module");

tests/baselines/reference/sideEffectImports3(moduledetection=legacy,nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+

tests/baselines/reference/sideEffectImports3(moduledetection=legacy,nouncheckedsideeffectimports=false).types

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log("Hello, world!") : void
+>                             : ^^^^
+>console.log : (...data: any[]) => void
+>            : ^^^^    ^^     ^^^^^    
+>console : Console
+>        : ^^^^^^^
+>log : (...data: any[]) => void
+>    : ^^^^    ^^     ^^^^^    
+>"Hello, world!" : "Hello, world!"
+>                : ^^^^^^^^^^^^^^^
+

tests/baselines/reference/sideEffectImports3(moduledetection=legacy,nouncheckedsideeffectimports=true).js

@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+//// [index.ts]
+import "./not-a-module";
+
+//// [not-a-module.ts]
+console.log("Hello, world!");
+
+
+//// [not-a-module.js]
+console.log("Hello, world!");
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("./not-a-module");

tests/baselines/reference/sideEffectImports3(moduledetection=legacy,nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+

tests/baselines/reference/sideEffectImports3(moduledetection=legacy,nouncheckedsideeffectimports=true).types

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/sideEffectImports3.ts] ////
+
+=== index.ts ===
+
+import "./not-a-module";
+
+=== not-a-module.ts ===
+console.log("Hello, world!");
+>console.log("Hello, world!") : void
+>                             : ^^^^
+>console.log : (...data: any[]) => void
+>            : ^^^^    ^^     ^^^^^    
+>console : Console
+>        : ^^^^^^^
+>log : (...data: any[]) => void
+>    : ^^^^    ^^     ^^^^^    
+>"Hello, world!" : "Hello, world!"
+>                : ^^^^^^^^^^^^^^^
+

tests/baselines/reference/sideEffectImports4(nouncheckedsideeffectimports=false).js

@@ -0,0 +1,33 @@
+//// [tests/cases/compiler/sideEffectImports4.ts] ////
+
+//// [package.json]
+{
+  "name": "server-only",
+  "version": "0.0.1",
+  "main": "index.js",
+  "exports": {
+    ".": {
+      "react-server": "./empty.js",
+      "default": "./index.js"
+    }
+  }
+}
+
+//// [index.js]
+throw new Error();
+
+//// [empty.js]
+// Empty
+
+//// [package.json]
+{
+    "name": "root",
+    "type": "module"
+}
+
+//// [index.ts]
+import "server-only";
+
+
+//// [index.js]
+import "server-only";

tests/baselines/reference/sideEffectImports4(nouncheckedsideeffectimports=false).symbols

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports4.ts] ////
+
+=== index.ts ===
+
+import "server-only";
+

tests/baselines/reference/sideEffectImports4(nouncheckedsideeffectimports=false).types

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports4.ts] ////
+
+=== index.ts ===
+
+import "server-only";
+

tests/baselines/reference/sideEffectImports4(nouncheckedsideeffectimports=true).js

@@ -0,0 +1,33 @@
+//// [tests/cases/compiler/sideEffectImports4.ts] ////
+
+//// [package.json]
+{
+  "name": "server-only",
+  "version": "0.0.1",
+  "main": "index.js",
+  "exports": {
+    ".": {
+      "react-server": "./empty.js",
+      "default": "./index.js"
+    }
+  }
+}
+
+//// [index.js]
+throw new Error();
+
+//// [empty.js]
+// Empty
+
+//// [package.json]
+{
+    "name": "root",
+    "type": "module"
+}
+
+//// [index.ts]
+import "server-only";
+
+
+//// [index.js]
+import "server-only";

tests/baselines/reference/sideEffectImports4(nouncheckedsideeffectimports=true).symbols

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports4.ts] ////
+
+=== index.ts ===
+
+import "server-only";
+

tests/baselines/reference/sideEffectImports4(nouncheckedsideeffectimports=true).types

@@ -0,0 +1,6 @@
+//// [tests/cases/compiler/sideEffectImports4.ts] ////
+
+=== index.ts ===
+
+import "server-only";
+

tests/baselines/reference/tscWatch/programUpdates/when-changing-noUncheckedSideEffectImports-of-config-file.js

@@ -0,0 +1,172 @@
+currentDirectory:: /user/username/projects/myproject useCaseSensitiveFileNames: false
+Input::
+//// [/user/username/projects/myproject/a.ts]
+import "does-not-exist";
+
+//// [/user/username/projects/myproject/tsconfig.json]
+{
+  "compilerOptions": {
+    "noUncheckedSideEffectImports": false
+  }
+}
+
+//// [/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; }
+
+
+/a/lib/tsc.js -w -p . --extendedDiagnostics
+Output::
+[HH:MM:SS AM] Starting compilation in watch mode...
+
+Current directory: /user/username/projects/myproject CaseSensitiveFileNames: false
+FileWatcher:: Added:: WatchInfo: /user/username/projects/myproject/tsconfig.json 2000 undefined Config file
+Synchronizing program
+CreatingProgramWith::
+  roots: ["/user/username/projects/myproject/a.ts"]
+  options: {"noUncheckedSideEffectImports":false,"watch":true,"project":"/user/username/projects/myproject","extendedDiagnostics":true,"configFilePath":"/user/username/projects/myproject/tsconfig.json"}
+FileWatcher:: Added:: WatchInfo: /user/username/projects/myproject/a.ts 250 undefined Source file
+FileWatcher:: Added:: WatchInfo: /a/lib/lib.d.ts 250 undefined Source file
+DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/myproject/node_modules 1 undefined Failed Lookup Locations
+Elapsed:: *ms DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/myproject/node_modules 1 undefined Failed Lookup Locations
+DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/node_modules 1 undefined Failed Lookup Locations
+Elapsed:: *ms DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/node_modules 1 undefined Failed Lookup Locations
+DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/myproject/node_modules/@types 1 undefined Type roots
+Elapsed:: *ms DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/myproject/node_modules/@types 1 undefined Type roots
+DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/node_modules/@types 1 undefined Type roots
+Elapsed:: *ms DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/node_modules/@types 1 undefined Type roots
+[HH:MM:SS AM] Found 0 errors. Watching for file changes.
+
+DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/myproject 1 undefined Wild card directory
+Elapsed:: *ms DirectoryWatcher:: Added:: WatchInfo: /user/username/projects/myproject 1 undefined Wild card directory
+
+
+//// [/user/username/projects/myproject/a.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("does-not-exist");
+
+
+
+PolledWatches::
+/user/username/projects/myproject/node_modules: *new*
+  {"pollingInterval":500}
+/user/username/projects/myproject/node_modules/@types: *new*
+  {"pollingInterval":500}
+/user/username/projects/node_modules: *new*
+  {"pollingInterval":500}
+/user/username/projects/node_modules/@types: *new*
+  {"pollingInterval":500}
+
+FsWatches::
+/a/lib/lib.d.ts: *new*
+  {}
+/user/username/projects/myproject/a.ts: *new*
+  {}
+/user/username/projects/myproject/tsconfig.json: *new*
+  {}
+
+FsWatchesRecursive::
+/user/username/projects/myproject: *new*
+  {}
+
+Program root files: [
+  "/user/username/projects/myproject/a.ts"
+]
+Program options: {
+  "noUncheckedSideEffectImports": false,
+  "watch": true,
+  "project": "/user/username/projects/myproject",
+  "extendedDiagnostics": true,
+  "configFilePath": "/user/username/projects/myproject/tsconfig.json"
+}
+Program structureReused: Not
+Program files::
+/a/lib/lib.d.ts
+/user/username/projects/myproject/a.ts
+
+Semantic diagnostics in builder refreshed for::
+/a/lib/lib.d.ts
+/user/username/projects/myproject/a.ts
+
+Shape signatures in builder refreshed for::
+/a/lib/lib.d.ts (used version)
+/user/username/projects/myproject/a.ts (used version)
+
+exitCode:: ExitStatus.undefined
+
+Change:: Change noUncheckedSideEffectImports to true
+
+Input::
+//// [/user/username/projects/myproject/tsconfig.json]
+{
+  "compilerOptions": {
+    "noUncheckedSideEffectImports": true
+  }
+}
+
+
+Output::
+FileWatcher:: Triggered with /user/username/projects/myproject/tsconfig.json 1:: WatchInfo: /user/username/projects/myproject/tsconfig.json 2000 undefined Config file
+Scheduling update
+Elapsed:: *ms FileWatcher:: Triggered with /user/username/projects/myproject/tsconfig.json 1:: WatchInfo: /user/username/projects/myproject/tsconfig.json 2000 undefined Config file
+
+
+Timeout callback:: count: 1
+1: timerToUpdateProgram *new*
+
+Before running Timeout callback:: count: 1
+1: timerToUpdateProgram
+
+Host is moving to new time
+After running Timeout callback:: count: 0
+Output::
+Reloading config file: /user/username/projects/myproject/tsconfig.json
+Synchronizing program
+[HH:MM:SS AM] File change detected. Starting incremental compilation...
+
+CreatingProgramWith::
+  roots: ["/user/username/projects/myproject/a.ts"]
+  options: {"noUncheckedSideEffectImports":true,"watch":true,"project":"/user/username/projects/myproject","extendedDiagnostics":true,"configFilePath":"/user/username/projects/myproject/tsconfig.json"}
+a.ts:1:8 - error TS2307: Cannot find module 'does-not-exist' or its corresponding type declarations.
+
+1 import "does-not-exist";
+         ~~~~~~~~~~~~~~~~
+
+[HH:MM:SS AM] Found 1 error. Watching for file changes.
+
+
+
+
+
+Program root files: [
+  "/user/username/projects/myproject/a.ts"
+]
+Program options: {
+  "noUncheckedSideEffectImports": true,
+  "watch": true,
+  "project": "/user/username/projects/myproject",
+  "extendedDiagnostics": true,
+  "configFilePath": "/user/username/projects/myproject/tsconfig.json"
+}
+Program structureReused: Completely
+Program files::
+/a/lib/lib.d.ts
+/user/username/projects/myproject/a.ts
+
+Semantic diagnostics in builder refreshed for::
+/a/lib/lib.d.ts
+/user/username/projects/myproject/a.ts
+
+No shapes updated in the builder::
+
+exitCode:: ExitStatus.undefined

tests/cases/compiler/sideEffectImports1.ts

@@ -0,0 +1,6 @@
+// @noUncheckedSideEffectImports: true,false
+// @module: commonjs,nodenext,preserve
+
+import "does-not-exist";
+import "./does-not-exist-either";
+import "./does-not-exist-either.js";

tests/cases/compiler/sideEffectImports2.ts

@@ -0,0 +1,17 @@
+// @noUncheckedSideEffectImports: true,false
+// @module: nodenext
+// @noImplicitAny: true,false
+// @noEmit: true
+
+// @filename: tsconfig.json
+{
+    "include": ["index.ts"],
+}
+
+// @filename: index.ts
+
+import "source-map-support/register";
+
+// @filename: node_modules/source-map-support/register.js
+
+module.exports = {};

tests/cases/compiler/sideEffectImports3.ts

@@ -0,0 +1,9 @@
+// @noUncheckedSideEffectImports: true,false
+// @module: nodenext
+// @moduleDetection: legacy,auto,force
+
+// @filename: index.ts
+import "./not-a-module";
+
+// @filename: not-a-module.ts
+console.log("Hello, world!");

tests/cases/compiler/sideEffectImports4.ts

@@ -0,0 +1,36 @@
+// @noUncheckedSideEffectImports: true,false
+// @strict: true
+// @noImplicitReferences: true
+// @module: esnext
+// @moduleResolution: bundler
+// @moduleDetection: force
+// @allowJs: true
+// @checkJs: true
+
+// @filename: node_modules/server-only/package.json
+{
+  "name": "server-only",
+  "version": "0.0.1",
+  "main": "index.js",
+  "exports": {
+    ".": {
+      "react-server": "./empty.js",
+      "default": "./index.js"
+    }
+  }
+}
+
+// @filename: node_modules/server-only/index.js
+throw new Error();
+
+// @filename: node_modules/server-only/empty.js
+// Empty
+
+// @filename: package.json
+{
+    "name": "root",
+    "type": "module"
+}
+
+// @filename: index.ts
+import "server-only";

tests/cases/fourslash/sideEffectImportsSuggestion1.ts

@@ -0,0 +1,19 @@
+/// <reference path="fourslash.ts" />
+
+// @allowJs: true
+// @noEmit: true
+// @module: commonjs
+// @noUncheckedSideEffectImports: true
+
+// @filename: moduleA/a.js
+//// import "b";
+//// import "c";
+
+// @filename: node_modules/b.ts
+//// var a = 10;
+
+// @filename: node_modules/c.js
+//// exports.a = 10;
+//// c = 10;
+
+verify.getSuggestionDiagnostics([]);