Issue35876: Give better error message when Classic Module Resolution with incorrect path

src/compiler/checker.ts

@@ -2598,7 +2598,7 @@ namespace ts {
         }
 
         function getExternalModuleMember(node: ImportDeclaration | ExportDeclaration, specifier: ImportOrExportSpecifier, dontResolveAlias = false): Symbol | undefined {
-            const moduleSymbol = resolveExternalModuleName(node, node.moduleSpecifier!)!; // TODO: GH#18217
+            const moduleSymbol = resolveExternalModuleName(node, node.moduleSpecifier!)!;
             const name = specifier.propertyName || specifier.name;
             const suppressInteropError = name.escapedText === InternalSymbolName.Default && !!(compilerOptions.allowSyntheticDefaultImports || compilerOptions.esModuleInterop);
             const targetSymbol = resolveESModuleSymbol(moduleSymbol, node.moduleSpecifier!, dontResolveAlias, suppressInteropError);
@@ -3105,9 +3105,12 @@ namespace ts {
             }
         }
 
-
         function resolveExternalModuleName(location: Node, moduleReferenceExpression: Expression, ignoreErrors?: boolean): Symbol | undefined {
-            return resolveExternalModuleNameWorker(location, moduleReferenceExpression, ignoreErrors ? undefined : Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations);
+            const isClassic = getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.Classic;
+            const errorMessage = isClassic?
+                                    Diagnostics.Cannot_find_module_0_Did_you_mean_to_set_the_moduleResolution_option_to_node_or_to_add_aliases_to_the_paths_option
+                                  : Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations;
+            return resolveExternalModuleNameWorker(location, moduleReferenceExpression, ignoreErrors ? undefined : errorMessage);
         }
 
         function resolveExternalModuleNameWorker(location: Node, moduleReferenceExpression: Expression, moduleNotFoundError: DiagnosticMessage | undefined, isForAugmentation = false): Symbol | undefined {

src/compiler/diagnosticMessages.json

@@ -2996,6 +2996,11 @@
         "category": "Error",
         "code": 2791
     },
+    "Cannot find module '{0}'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?": {
+        "category": "Error",
+        "code": 2792
+    },
+
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

src/testRunner/unittests/tscWatch/helpers.ts

@@ -267,7 +267,7 @@ namespace ts.tscWatch {
 
     export function getDiagnosticModuleNotFoundOfFile(program: Program, file: File, moduleName: string) {
         const quotedModuleName = `"${moduleName}"`;
-        return getDiagnosticOfFileFromProgram(program, file.path, file.content.indexOf(quotedModuleName), quotedModuleName.length, Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations, moduleName);
+        return getDiagnosticOfFileFromProgram(program, file.path, file.content.indexOf(quotedModuleName), quotedModuleName.length, Diagnostics.Cannot_find_module_0_Did_you_mean_to_set_the_moduleResolution_option_to_node_or_to_add_aliases_to_the_paths_option, moduleName);
     }
 
     export function runQueuedTimeoutCallbacks(sys: WatchedSystem) {

src/testRunner/unittests/tsserver/cachingFileSystemInformation.ts

@@ -240,8 +240,8 @@ namespace ts.projectSystem {
             let diags = project.getLanguageService().getSemanticDiagnostics(root.path);
             assert.equal(diags.length, 1);
             const diag = diags[0];
-            assert.equal(diag.code, Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations.code);
-            assert.equal(flattenDiagnosticMessageText(diag.messageText, "\n"), "Cannot find module 'bar' or its corresponding type declarations.");
+            assert.equal(diag.code, Diagnostics.Cannot_find_module_0_Did_you_mean_to_set_the_moduleResolution_option_to_node_or_to_add_aliases_to_the_paths_option.code);
+            assert.equal(flattenDiagnosticMessageText(diag.messageText, "\n"), "Cannot find module 'bar'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?");
             callsTrackingHost.verifyCalledOn(CalledMapsWithSingleArg.fileExists, imported.path);
 
 

src/testRunner/unittests/tsserver/symLinks.ts

@@ -210,7 +210,7 @@ new C();`
                         verifyWatchedFilesAndDirectories(session.testhost, filesInProjectWithUnresolvedModule, watchedDirectoriesWithUnresolvedModule, nonRecursiveWatchedDirectories);
                         const startOffset = recognizersDateTimeSrcFile.content.indexOf('"') + 1;
                         verifyErrors(session, [
-                            createDiagnostic({ line: 1, offset: startOffset }, { line: 1, offset: startOffset + moduleNameInFile.length }, Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations, [moduleName])
+                            createDiagnostic({ line: 1, offset: startOffset }, { line: 1, offset: startOffset + moduleNameInFile.length }, Diagnostics.Cannot_find_module_0_Did_you_mean_to_set_the_moduleResolution_option_to_node_or_to_add_aliases_to_the_paths_option, [moduleName])
                         ]);
                     }
 

tests/baselines/reference/aliasesInSystemModule1.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/compiler/aliasesInSystemModule1.ts(1,24): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+tests/cases/compiler/aliasesInSystemModule1.ts(1,24): error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/aliasesInSystemModule1.ts (1 errors) ====
     import alias = require('foo');
                            ~~~~~
-!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     import cls = alias.Class;
     export import cls2 = alias.Class;
 

tests/baselines/reference/aliasesInSystemModule2.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/compiler/aliasesInSystemModule2.ts(1,21): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+tests/cases/compiler/aliasesInSystemModule2.ts(1,21): error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/aliasesInSystemModule2.ts (1 errors) ====
     import {alias} from "foo";
                         ~~~~~
-!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     import cls = alias.Class;
     export import cls2 = alias.Class;
 

tests/baselines/reference/ambientExternalModuleInAnotherExternalModule.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts(4,16): error TS2664: Invalid module name in augmentation, module 'ext' cannot be found.
-tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts(9,22): error TS2307: Cannot find module 'ext' or its corresponding type declarations.
+tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts(9,22): error TS2792: Cannot find module 'ext'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts (2 errors) ====
@@ -15,5 +15,5 @@ tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts(9,22): erro
     // Cannot resolve this ext module reference
     import ext = require("ext");
                          ~~~~~
-!!! error TS2307: Cannot find module 'ext' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'ext'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     var x = ext;

tests/baselines/reference/amdDependencyComment2.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/compiler/amdDependencyComment2.ts(3,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
+tests/cases/compiler/amdDependencyComment2.ts(3,21): error TS2792: Cannot find module 'm2'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/amdDependencyComment2.ts (1 errors) ====
     ///<amd-dependency path='bar'/>
 
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'm2'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     m1.f();

tests/baselines/reference/amdDependencyCommentName2.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/compiler/amdDependencyCommentName2.ts(3,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
+tests/cases/compiler/amdDependencyCommentName2.ts(3,21): error TS2792: Cannot find module 'm2'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/amdDependencyCommentName2.ts (1 errors) ====
     ///<amd-dependency path='bar' name='b'/>
 
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'm2'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     m1.f();

tests/baselines/reference/amdDependencyCommentName3.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/amdDependencyCommentName3.ts(5,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
+tests/cases/compiler/amdDependencyCommentName3.ts(5,21): error TS2792: Cannot find module 'm2'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/amdDependencyCommentName3.ts (1 errors) ====
@@ -8,5 +8,5 @@ tests/cases/compiler/amdDependencyCommentName3.ts(5,21): error TS2307: Cannot fi
 
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'm2'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     m1.f();

tests/baselines/reference/amdDependencyCommentName4.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/compiler/amdDependencyCommentName4.ts(8,21): error TS2307: Cannot find module 'aliasedModule1' or its corresponding type declarations.
-tests/cases/compiler/amdDependencyCommentName4.ts(11,26): error TS2307: Cannot find module 'aliasedModule2' or its corresponding type declarations.
-tests/cases/compiler/amdDependencyCommentName4.ts(14,15): error TS2307: Cannot find module 'aliasedModule3' or its corresponding type declarations.
-tests/cases/compiler/amdDependencyCommentName4.ts(17,21): error TS2307: Cannot find module 'aliasedModule4' or its corresponding type declarations.
+tests/cases/compiler/amdDependencyCommentName4.ts(8,21): error TS2792: Cannot find module 'aliasedModule1'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
+tests/cases/compiler/amdDependencyCommentName4.ts(11,26): error TS2792: Cannot find module 'aliasedModule2'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
+tests/cases/compiler/amdDependencyCommentName4.ts(14,15): error TS2792: Cannot find module 'aliasedModule3'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
+tests/cases/compiler/amdDependencyCommentName4.ts(17,21): error TS2792: Cannot find module 'aliasedModule4'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/amdDependencyCommentName4.ts (4 errors) ====
@@ -14,22 +14,22 @@ tests/cases/compiler/amdDependencyCommentName4.ts(17,21): error TS2307: Cannot f
 
     import r1 = require("aliasedModule1");
                         ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'aliasedModule1' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'aliasedModule1'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     r1;
 
     import {p1, p2, p3} from "aliasedModule2";
                              ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'aliasedModule2' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'aliasedModule2'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     p1;
 
     import d from "aliasedModule3";
                   ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'aliasedModule3' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'aliasedModule3'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     d;
 
     import * as ns from "aliasedModule4";
                         ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'aliasedModule4' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'aliasedModule4'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     ns;
 
     import "unaliasedModule2";

tests/baselines/reference/asyncAwaitIsolatedModules_es2017.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/conformance/async/es2017/asyncAwaitIsolatedModules_es2017.ts(1,27): error TS2307: Cannot find module 'missing' or its corresponding type declarations.
+tests/cases/conformance/async/es2017/asyncAwaitIsolatedModules_es2017.ts(1,27): error TS2792: Cannot find module 'missing'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/conformance/async/es2017/asyncAwaitIsolatedModules_es2017.ts (1 errors) ====
     import { MyPromise } from "missing";
                               ~~~~~~~~~
-!!! error TS2307: Cannot find module 'missing' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'missing'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
     declare var p: Promise<number>;
     declare var mp: MyPromise<number>;

tests/baselines/reference/asyncAwaitIsolatedModules_es6.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/conformance/async/es6/asyncAwaitIsolatedModules_es6.ts(1,27): error TS2307: Cannot find module 'missing' or its corresponding type declarations.
+tests/cases/conformance/async/es6/asyncAwaitIsolatedModules_es6.ts(1,27): error TS2792: Cannot find module 'missing'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/conformance/async/es6/asyncAwaitIsolatedModules_es6.ts (1 errors) ====
     import { MyPromise } from "missing";
                               ~~~~~~~~~
-!!! error TS2307: Cannot find module 'missing' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'missing'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
     declare var p: Promise<number>;
     declare var mp: MyPromise<number>;

tests/baselines/reference/badExternalModuleReference.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/compiler/badExternalModuleReference.ts(1,21): error TS2307: Cannot find module 'garbage' or its corresponding type declarations.
+tests/cases/compiler/badExternalModuleReference.ts(1,21): error TS2792: Cannot find module 'garbage'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/badExternalModuleReference.ts (1 errors) ====
     import a1 = require("garbage");
                         ~~~~~~~~~
-!!! error TS2307: Cannot find module 'garbage' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'garbage'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
     export declare var a: {
         test1: a1.connectModule;
         (): a1.connectExport;

tests/baselines/reference/cachedModuleResolution8.errors.txt

@@ -1,13 +1,13 @@
-/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
-/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+/a/b/c/d/e/app.ts(1,17): error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
+/a/b/c/lib.ts(1,17): error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== /a/b/c/d/e/app.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 ==== /a/b/c/lib.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?

tests/baselines/reference/cachedModuleResolution9.errors.txt

@@ -1,15 +1,15 @@
-/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
-/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+/a/b/c/d/e/app.ts(1,17): error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
+/a/b/c/lib.ts(1,17): error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== /a/b/c/lib.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== /a/b/c/d/e/app.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+!!! error TS2792: Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 

tests/baselines/reference/commentOnImportStatement1.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/compiler/commentOnImportStatement1.ts(3,22): error TS2307: Cannot find module './foo' or its corresponding type declarations.
+tests/cases/compiler/commentOnImportStatement1.ts(3,22): error TS2792: Cannot find module './foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?
 
 
 ==== tests/cases/compiler/commentOnImportStatement1.ts (1 errors) ====
     /* Copyright */
 
     import foo = require('./foo');
                          ~~~~~~~
-!!! error TS2307: Cannot find module './foo' or its corresponding type declarations.
+!!! error TS2792: Cannot find module './foo'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option?