microsoft · Sep 19, 2017 · Sep 14, 2017 · Sep 15, 2017
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -1759,13 +1759,13 @@ namespace ts {
             }
 
             // May be an untyped module. If so, ignore resolutionDiagnostic.
-            if (resolvedModule && resolvedModule.isExternalLibraryImport && !extensionIsTypeScript(resolvedModule.extension)) {
+            if (resolvedModule && !extensionIsTypeScript(resolvedModule.extension) && resolutionDiagnostic === undefined || resolutionDiagnostic === Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type) {
                 if (isForAugmentation) {
                     const diag = Diagnostics.Invalid_module_name_in_augmentation_Module_0_resolves_to_an_untyped_module_at_1_which_cannot_be_augmented;
                     error(errorNode, diag, moduleReference, resolvedModule.resolvedFileName);
                 }
                 else if (noImplicitAny && moduleNotFoundError) {
-                    let errorInfo = chainDiagnosticMessages(/*details*/ undefined,
+                    let errorInfo = !resolvedModule.isExternalLibraryImport ? undefined : chainDiagnosticMessages(/*details*/ undefined,
                         Diagnostics.Try_npm_install_types_Slash_0_if_it_exists_or_add_a_new_declaration_d_ts_file_containing_declare_module_0,
                         moduleReference);
                     errorInfo = chainDiagnosticMessages(errorInfo,

diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
@@ -3146,10 +3146,6 @@
         "category": "Error",
         "code": 6142
     },
-    "Module '{0}' was resolved to '{1}', but '--allowJs' is not set.": {
-        "category": "Error",
-        "code": 6143
-    },
     "Module '{0}' was resolved as locally declared ambient module in file '{1}'.": {
         "category": "Message",
         "code": 6144

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
@@ -1846,7 +1846,8 @@ namespace ts {
                     }
 
                     const isFromNodeModulesSearch = resolution.isExternalLibraryImport;
-                    const isJsFileFromNodeModules = isFromNodeModulesSearch && !extensionIsTypeScript(resolution.extension);
+                    const isJsFile = !extensionIsTypeScript(resolution.extension);
+                    const isJsFileFromNodeModules = isFromNodeModulesSearch && isJsFile;
                     const resolvedFileName = resolution.resolvedFileName;
 
                     if (isFromNodeModulesSearch) {
@@ -1861,7 +1862,12 @@ namespace ts {
                     const elideImport = isJsFileFromNodeModules && currentNodeModulesDepth > maxNodeModuleJsDepth;
                     // Don't add the file if it has a bad extension (e.g. 'tsx' if we don't have '--allowJs')
                     // This may still end up being an untyped module -- the file won't be included but imports will be allowed.
-                    const shouldAddFile = resolvedFileName && !getResolutionDiagnostic(options, resolution) && !options.noResolve && i < file.imports.length && !elideImport;
+                    const shouldAddFile = resolvedFileName
+                        && !getResolutionDiagnostic(options, resolution)
+                        && !options.noResolve
+                        && i < file.imports.length
+                        && !elideImport
+                        && !(isJsFile && !options.allowJs);
 
                     if (elideImport) {
                         modulesWithElidedImports.set(file.path, true);
@@ -2236,7 +2242,7 @@ namespace ts {
             return options.jsx ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
         }
         function needAllowJs() {
-            return options.allowJs ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set;
+            return options.allowJs || !options.noImplicitAny ? undefined : Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type;
         }
     }
 

diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt
@@ -1,18 +1,15 @@
 /a.ts(1,17): error TS6142: Module './tsx' was resolved to '/tsx.tsx', but '--jsx' is not set.
 /a.ts(2,17): error TS6142: Module './jsx' was resolved to '/jsx.jsx', but '--jsx' is not set.
-/a.ts(3,16): error TS6143: Module './js' was resolved to '/js.js', but '--allowJs' is not set.
 
 
-==== /a.ts (3 errors) ====
-    import tsx from "./tsx";
+==== /a.ts (2 errors) ====
+    import tsx from "./tsx"; // Not allowed.
                     ~~~~~~~
 !!! error TS6142: Module './tsx' was resolved to '/tsx.tsx', but '--jsx' is not set.
-    import jsx from "./jsx";
+    import jsx from "./jsx"; // Not allowed.
                     ~~~~~~~
 !!! error TS6142: Module './jsx' was resolved to '/jsx.jsx', but '--jsx' is not set.
-    import js from "./js";
-                   ~~~~~~
-!!! error TS6143: Module './js' was resolved to '/js.js', but '--allowJs' is not set.
+    import js from "./js"; // OK because it's an untyped module.
 
 ==== /tsx.tsx (0 errors) ====
 

diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.js b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.js
@@ -7,9 +7,9 @@
 //// [js.js]
 
 //// [a.ts]
-import tsx from "./tsx";
-import jsx from "./jsx";
-import js from "./js";
+import tsx from "./tsx"; // Not allowed.
+import jsx from "./jsx"; // Not allowed.
+import js from "./js"; // OK because it's an untyped module.
 
 
 //// [a.js]

diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.errors.txt b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.errors.txt
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.js b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.js
@@ -1,7 +1,7 @@
 //// [tests/cases/compiler/moduleResolutionWithExtensions_notSupported3.ts] ////
 
 //// [jsx.jsx]
-// Test the error message if we have `--jsx` but not `--allowJw`.
+// If we have "--jsx" set and not "--allowJs", it's an implicit-any module.
 
 
 //// [a.ts]

diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.symbols b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.symbols
@@ -0,0 +1,4 @@
+=== /a.ts ===
+import jsx from "./jsx";
+>jsx : Symbol(jsx, Decl(a.ts, 0, 6))
+
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.types b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.types
@@ -0,0 +1,4 @@
+=== /a.ts ===
+import jsx from "./jsx";
+>jsx : any
+
diff --git a/tests/baselines/reference/moduleResolution_relativeImportJsFile.js b/tests/baselines/reference/moduleResolution_relativeImportJsFile.js
@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/moduleResolution_relativeImportJsFile.ts] ////
+
+//// [b.js]
+export const x = 0;
+
+//// [a.ts]
+import * as b from "./b";
+
+
+//// [a.js]
+"use strict";
+exports.__esModule = true;
diff --git a/tests/baselines/reference/moduleResolution_relativeImportJsFile.symbols b/tests/baselines/reference/moduleResolution_relativeImportJsFile.symbols
@@ -0,0 +1,4 @@
+=== /src/a.ts ===
+import * as b from "./b";
+>b : Symbol(b, Decl(a.ts, 0, 6))
+
diff --git a/tests/baselines/reference/moduleResolution_relativeImportJsFile.types b/tests/baselines/reference/moduleResolution_relativeImportJsFile.types
@@ -0,0 +1,4 @@
+=== /src/a.ts ===
+import * as b from "./b";
+>b : any
+
diff --git a/tests/baselines/reference/moduleResolution_relativeImportJsFile_noImplicitAny.errors.txt b/tests/baselines/reference/moduleResolution_relativeImportJsFile_noImplicitAny.errors.txt
@@ -0,0 +1,11 @@
+/src/a.ts(1,20): error TS7016: Could not find a declaration file for module './b'. '/src/b.js' implicitly has an 'any' type.
+
+
+==== /src/a.ts (1 errors) ====
+    import * as b from "./b";
+                       ~~~~~
+!!! error TS7016: Could not find a declaration file for module './b'. '/src/b.js' implicitly has an 'any' type.
+
+==== /src/b.js (0 errors) ====
+    export const x = 0;
+
diff --git a/tests/baselines/reference/moduleResolution_relativeImportJsFile_noImplicitAny.js b/tests/baselines/reference/moduleResolution_relativeImportJsFile_noImplicitAny.js
@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/moduleResolution_relativeImportJsFile_noImplicitAny.ts] ////
+
+//// [b.js]
+export const x = 0;
+
+//// [a.ts]
+import * as b from "./b";
+
+
+//// [a.js]
+"use strict";
+exports.__esModule = true;
diff --git a/tests/cases/compiler/moduleResolutionWithExtensions_notSupported.ts b/tests/cases/compiler/moduleResolutionWithExtensions_notSupported.ts
@@ -8,6 +8,6 @@
 // @Filename: /js.js
 
 // @Filename: /a.ts
-import tsx from "./tsx";
-import jsx from "./jsx";
-import js from "./js";
+import tsx from "./tsx"; // Not allowed.
+import jsx from "./jsx"; // Not allowed.
+import js from "./js"; // OK because it's an untyped module.
diff --git a/tests/cases/compiler/moduleResolutionWithExtensions_notSupported3.ts b/tests/cases/compiler/moduleResolutionWithExtensions_notSupported3.ts
@@ -1,7 +1,7 @@
 // @noImplicitReferences: true
 // @jsx: preserve
 // @traceResolution: true
-// Test the error message if we have `--jsx` but not `--allowJw`.
+// If we have "--jsx" set and not "--allowJs", it's an implicit-any module.
 
 // @Filename: /jsx.jsx
 

diff --git a/tests/cases/compiler/moduleResolution_relativeImportJsFile.ts b/tests/cases/compiler/moduleResolution_relativeImportJsFile.ts
@@ -0,0 +1,7 @@
+// @noImplicitReferences: true
+
+// @Filename: /src/b.js
+export const x = 0;
+
+// @Filename: /src/a.ts
+import * as b from "./b";
diff --git a/tests/cases/compiler/moduleResolution_relativeImportJsFile_noImplicitAny.ts b/tests/cases/compiler/moduleResolution_relativeImportJsFile_noImplicitAny.ts
@@ -0,0 +1,8 @@
+// @noImplicitReferences: true
+// @noImplicitAny: true
+
+// @Filename: /src/b.js
+export const x = 0;
+
+// @Filename: /src/a.ts
+import * as b from "./b";
diff --git a/tests/cases/conformance/moduleResolution/untypedModuleImport_noLocalImports.ts b/tests/cases/conformance/moduleResolution/untypedModuleImport_noLocalImports.ts