Ensure self-name resolution uses same extension priorities as external imports

src/compiler/moduleNameResolver.ts

@@ -2313,7 +2313,18 @@ function loadModuleFromSelfNameReference(extensions: Extensions, moduleName: str
         return undefined;
     }
     const trailingParts = parts.slice(nameParts.length);
-    return loadModuleFromExports(scope, extensions, !length(trailingParts) ? "." : `.${directorySeparator}${trailingParts.join(directorySeparator)}`, state, cache, redirectedReference);
+    const subpath = !length(trailingParts) ? "." : `.${directorySeparator}${trailingParts.join(directorySeparator)}`;
+    // Maybe TODO: splitting extensions into two priorities should be unnecessary, except
+    // https://github.com/microsoft/TypeScript/issues/50762 makes the behavior different.
+    // As long as that bug exists, we need to do two passes here in self-name loading
+    // in order to be consistent with (non-self) library-name loading in
+    // `loadModuleFromNearestNodeModulesDirectoryWorker`, which uses two passes in order
+    // to prioritize `@types` packages higher up the directory tree over untyped
+    // implementation packages.
+    const priorityExtensions = extensions & (Extensions.TypeScript | Extensions.Declaration);
+    const secondaryExtensions = extensions & ~(Extensions.TypeScript | Extensions.Declaration);
+    return loadModuleFromExports(scope, priorityExtensions, subpath, state, cache, redirectedReference)
+        || loadModuleFromExports(scope, secondaryExtensions, subpath, state, cache, redirectedReference);
 }
 
 function loadModuleFromExports(scope: PackageJsonInfo, extensions: Extensions, subpath: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): SearchResult<Resolved> {

tests/baselines/reference/selfNameModuleAugmentation.symbols

@@ -0,0 +1,21 @@
+=== /node_modules/acorn-walk/dist/walk.d.ts ===
+export {};
+declare module 'acorn-walk' {
+>'acorn-walk' : Symbol("/node_modules/acorn-walk/dist/walk", Decl(walk.d.ts, 0, 0), Decl(walk.d.ts, 0, 10))
+
+  export function simple(node: any, visitors: any, base?: any, state?: any): any;
+>simple : Symbol(simple, Decl(walk.d.ts, 1, 29))
+>node : Symbol(node, Decl(walk.d.ts, 2, 25))
+>visitors : Symbol(visitors, Decl(walk.d.ts, 2, 35))
+>base : Symbol(base, Decl(walk.d.ts, 2, 50))
+>state : Symbol(state, Decl(walk.d.ts, 2, 62))
+}
+
+=== /node_modules/acorn-walk/dist/walk.mjs ===
+
+export {};
+
+=== /index.ts ===
+import { simple } from 'acorn-walk';
+>simple : Symbol(simple, Decl(index.ts, 0, 8))
+

tests/baselines/reference/selfNameModuleAugmentation.trace.json

@@ -0,0 +1,39 @@
+[
+    "======== Resolving module 'acorn-walk' from '/node_modules/acorn-walk/dist/walk.d.ts'. ========",
+    "Explicitly specified module resolution kind: 'Bundler'.",
+    "File '/node_modules/acorn-walk/dist/package.json' does not exist.",
+    "Found 'package.json' at '/node_modules/acorn-walk/package.json'.",
+    "Matched 'exports' condition 'import'.",
+    "Using 'exports' subpath '.' with target './dist/walk.mjs'.",
+    "File name '/node_modules/acorn-walk/dist/walk.mjs' has a '.mjs' extension - stripping it.",
+    "File '/node_modules/acorn-walk/dist/walk.mts' does not exist.",
+    "File '/node_modules/acorn-walk/dist/walk.d.mts' does not exist.",
+    "Saw non-matching condition 'require'.",
+    "Matched 'exports' condition 'default'.",
+    "Using 'exports' subpath '.' with target './dist/walk.js'.",
+    "File name '/node_modules/acorn-walk/dist/walk.js' has a '.js' extension - stripping it.",
+    "File '/node_modules/acorn-walk/dist/walk.ts' does not exist.",
+    "File '/node_modules/acorn-walk/dist/walk.tsx' does not exist.",
+    "File '/node_modules/acorn-walk/dist/walk.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/acorn-walk/dist/walk.d.ts', result '/node_modules/acorn-walk/dist/walk.d.ts'.",
+    "======== Module name 'acorn-walk' was successfully resolved to '/node_modules/acorn-walk/dist/walk.d.ts' with Package ID 'acorn-walk/dist/walk.d.ts@8.2.0'. ========",
+    "======== Resolving module 'acorn-walk' from '/index.ts'. ========",
+    "Explicitly specified module resolution kind: 'Bundler'.",
+    "File '/package.json' does not exist.",
+    "Loading module 'acorn-walk' from 'node_modules' folder, target file types: TypeScript, JavaScript, Declaration, JSON.",
+    "File '/node_modules/acorn-walk/package.json' exists according to earlier cached lookups.",
+    "Matched 'exports' condition 'import'.",
+    "Using 'exports' subpath '.' with target './dist/walk.mjs'.",
+    "File name '/node_modules/acorn-walk/dist/walk.mjs' has a '.mjs' extension - stripping it.",
+    "File '/node_modules/acorn-walk/dist/walk.mts' does not exist.",
+    "File '/node_modules/acorn-walk/dist/walk.d.mts' does not exist.",
+    "Saw non-matching condition 'require'.",
+    "Matched 'exports' condition 'default'.",
+    "Using 'exports' subpath '.' with target './dist/walk.js'.",
+    "File name '/node_modules/acorn-walk/dist/walk.js' has a '.js' extension - stripping it.",
+    "File '/node_modules/acorn-walk/dist/walk.ts' does not exist.",
+    "File '/node_modules/acorn-walk/dist/walk.tsx' does not exist.",
+    "File '/node_modules/acorn-walk/dist/walk.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/acorn-walk/dist/walk.d.ts', result '/node_modules/acorn-walk/dist/walk.d.ts'.",
+    "======== Module name 'acorn-walk' was successfully resolved to '/node_modules/acorn-walk/dist/walk.d.ts' with Package ID 'acorn-walk/dist/walk.d.ts@8.2.0'. ========"
+]

tests/baselines/reference/selfNameModuleAugmentation.types

@@ -0,0 +1,21 @@
+=== /node_modules/acorn-walk/dist/walk.d.ts ===
+export {};
+declare module 'acorn-walk' {
+>'acorn-walk' : typeof import("/node_modules/acorn-walk/dist/walk")
+
+  export function simple(node: any, visitors: any, base?: any, state?: any): any;
+>simple : (node: any, visitors: any, base?: any, state?: any) => any
+>node : any
+>visitors : any
+>base : any
+>state : any
+}
+
+=== /node_modules/acorn-walk/dist/walk.mjs ===
+
+export {};
+
+=== /index.ts ===
+import { simple } from 'acorn-walk';
+>simple : (node: any, visitors: any, base?: any, state?: any) => any
+

tests/cases/conformance/moduleResolution/selfNameModuleAugmentation.ts

@@ -0,0 +1,43 @@
+// @moduleResolution: bundler
+// @allowJs: true
+// @noEmit: true
+// @traceResolution: true
+
+// @Filename: /node_modules/acorn-walk/package.json
+{
+  "name": "acorn-walk",
+  "version": "8.2.0",
+  "main": "dist/walk.js",
+  "types": "dist/walk.d.ts",
+  "exports": {
+    ".": [
+      {
+          "import": "./dist/walk.mjs",
+          "require": "./dist/walk.js",
+          "default": "./dist/walk.js"
+      },
+      "./dist/walk.js"
+    ],
+    "./package.json": "./package.json"
+  }
+}
+
+// The correct behavior for this test would be for both the module augmentation
+// and the import to resolve to `walk.mjs` (triggering at least one implicit any
+// error, I think?). However, https://github.com/microsoft/TypeScript/issues/50762
+// causes the import to resolve through the `default` condition, replacing `.js`
+// with `.d.ts` to find `walk.d.ts`. While this is incorrect, it's important that
+// the module augmentation, which resolves through self-name resolution, resolves
+// to the same module as the external import.
+
+// @Filename: /node_modules/acorn-walk/dist/walk.d.ts
+export {};
+declare module 'acorn-walk' {
+  export function simple(node: any, visitors: any, base?: any, state?: any): any;
+}
+
+// @Filename: /node_modules/acorn-walk/dist/walk.mjs
+export {};
+
+// @Filename: /index.ts
+import { simple } from 'acorn-walk';