Put ref into messages when we fail to follow a ref

src/JSONSchemaInput.ts

@@ -239,9 +239,10 @@ export class Ref {
     }
 
     private lookup(local: any, path: List<PathElement>, root: JSONSchema): JSONSchema {
+        const refMaker = () => new Ref(this.addressURI, path);
         const first = path.first();
         if (first === undefined) {
-            return checkJSONSchema(local, () => new Ref(this.addressURI, path));
+            return checkJSONSchema(local, refMaker);
         }
         const rest = path.rest();
         switch (first.kind) {
@@ -251,16 +252,16 @@ export class Ref {
                 const key = first.key;
                 if (Array.isArray(local)) {
                     if (!/^\d+$/.test(key)) {
-                        return messageError(ErrorMessage.SchemaCannotIndexArrayWithNonNumber, { actual: key });
+                        return messageError(ErrorMessage.SchemaCannotIndexArrayWithNonNumber, withRef(refMaker, { actual: key }));
                     }
                     const index = parseInt(first.key, 10);
                     if (index >= local.length) {
-                        return messageError(ErrorMessage.SchemaIndexNotInArray, { index });
+                        return messageError(ErrorMessage.SchemaIndexNotInArray, withRef(refMaker, { index }));
                     }
                     return this.lookup(local[index], rest, root);
                 } else {
                     if (!lodash.has(local, [key])) {
-                        return messageError(ErrorMessage.SchemaKeyNotInObject, { key });
+                        return messageError(ErrorMessage.SchemaKeyNotInObject, withRef(refMaker, { key }));
                     }
                     return this.lookup(checkStringMap(local)[first.key], rest, root);
                 }

src/Messages.ts

@@ -30,9 +30,9 @@ export class ErrorMessage {
     static SchemaCannotFetch = "Cannot fetch schema at address ${address}";
     static SchemaMoreThanOneUnionMemberName = "More than one name given for union member: ${names}";
     static SchemaCannotGetTypesFromBoolean = "Schema value to get top-level types from must be an object, but is boolean, at ${ref}";
-    static SchemaCannotIndexArrayWithNonNumber = "Trying to index array in schema with key that is not a number, but is ${actual}";
-    static SchemaIndexNotInArray = "Index out of range of schema array: ${index}";
-    static SchemaKeyNotInObject = "Key not in schema object: ${key}";
+    static SchemaCannotIndexArrayWithNonNumber = "Trying to index array in schema with key that is not a number, but is ${actual} at ${ref}";
+    static SchemaIndexNotInArray = "Index ${index} out of range of schema array at ${ref}";
+    static SchemaKeyNotInObject = "Key ${key} not in schema object at ${ref}";
 
     // GraphQL input
     static GraphQLNoQueriesDefined = "GraphQL file doesn't have any queries defined.";
@@ -95,9 +95,9 @@ type Error =
     | { message: ErrorMessage.SchemaCannotFetch; properties: { address: string } }
     | { message: ErrorMessage.SchemaMoreThanOneUnionMemberName; properties: { names: string[] } }
     | { message: ErrorMessage.SchemaCannotGetTypesFromBoolean; properties: { ref: string } }
-    | { message: ErrorMessage.SchemaCannotIndexArrayWithNonNumber; properties: { actual: string } }
-    | { message: ErrorMessage.SchemaIndexNotInArray; properties: { index: number } }
-    | { message: ErrorMessage.SchemaKeyNotInObject; properties: { key: string } }
+    | { message: ErrorMessage.SchemaCannotIndexArrayWithNonNumber; properties: { actual: string; ref: Ref } }
+    | { message: ErrorMessage.SchemaIndexNotInArray; properties: { index: number; ref: Ref } }
+    | { message: ErrorMessage.SchemaKeyNotInObject; properties: { key: string; ref: Ref } }
 
     // GraphQL input
     | { message: ErrorMessage.GraphQLNoQueriesDefined; properties: {} }