Allow subpath imports that start with #/

This aligns with Node.js PR nodejs/node#60864, which allows defining
symmetric `exports` and `imports` fields in package.json:

{
  "exports": { "./*": "./src/*" },
  "imports": { "#/*": "./src/*" }
}

Author: magic-akari

src/compiler/moduleNameResolver.ts

@@ -2646,7 +2646,7 @@ function loadModuleFromExports(scope: PackageJsonInfo, extensions: Extensions, s
 }
 
 function loadModuleFromImports(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): SearchResult<Resolved> {
-    if (moduleName === "#" || startsWith(moduleName, "#/")) {
+    if (moduleName === "#") {
         if (state.traceEnabled) {
             trace(state.host, Diagnostics.Invalid_import_specifier_0_has_no_possible_resolutions, moduleName);
         }

tests/baselines/reference/nodeModulesPackageImportsRootWildcard(module=node16).errors.txt

@@ -0,0 +1,51 @@
+index.cts(2,21): error TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("#/foo.js")' call instead.
+index.cts(3,21): error TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("#/features/bar.js")' call instead.
+index.cts(4,21): error TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("#/nested/deep/baz.js")' call instead.
+
+
+==== package.json (0 errors) ====
+    {
+        "name": "package",
+        "private": true,
+        "type": "module",
+        "imports": {
+            "#/*": "./src/*"
+        }
+    }
+==== src/foo.ts (0 errors) ====
+    export const foo = "foo";
+==== src/features/bar.ts (0 errors) ====
+    export const bar = "bar";
+==== src/nested/deep/baz.ts (0 errors) ====
+    export const baz = "baz";
+==== index.ts (0 errors) ====
+    // esm format file
+    import { foo } from "#/foo.js";
+    import { bar } from "#/features/bar.js";
+    import { baz } from "#/nested/deep/baz.js";
+    foo;
+    bar;
+    baz;
+==== index.mts (0 errors) ====
+    // esm format file
+    import { foo } from "#/foo.js";
+    import { bar } from "#/features/bar.js";
+    import { baz } from "#/nested/deep/baz.js";
+    foo;
+    bar;
+    baz;
+==== index.cts (3 errors) ====
+    // cjs format file
+    import { foo } from "#/foo.js";
+                        ~~~~~~~~~~
+!!! error TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("#/foo.js")' call instead.
+    import { bar } from "#/features/bar.js";
+                        ~~~~~~~~~~~~~~~~~~~
+!!! error TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("#/features/bar.js")' call instead.
+    import { baz } from "#/nested/deep/baz.js";
+                        ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("#/nested/deep/baz.js")' call instead.
+    foo;
+    bar;
+    baz;
+    

tests/baselines/reference/nodeModulesPackageImportsRootWildcard(module=node16).js

@@ -0,0 +1,89 @@
+//// [tests/cases/conformance/node/nodeModulesPackageImportsRootWildcard.ts] ////
+
+//// [package.json]
+{
+    "name": "package",
+    "private": true,
+    "type": "module",
+    "imports": {
+        "#/*": "./src/*"
+    }
+}
+//// [foo.ts]
+export const foo = "foo";
+//// [bar.ts]
+export const bar = "bar";
+//// [baz.ts]
+export const baz = "baz";
+//// [index.ts]
+// esm format file
+import { foo } from "#/foo.js";
+import { bar } from "#/features/bar.js";
+import { baz } from "#/nested/deep/baz.js";
+foo;
+bar;
+baz;
+//// [index.mts]
+// esm format file
+import { foo } from "#/foo.js";
+import { bar } from "#/features/bar.js";
+import { baz } from "#/nested/deep/baz.js";
+foo;
+bar;
+baz;
+//// [index.cts]
+// cjs format file
+import { foo } from "#/foo.js";
+import { bar } from "#/features/bar.js";
+import { baz } from "#/nested/deep/baz.js";
+foo;
+bar;
+baz;
+
+
+//// [foo.js]
+export const foo = "foo";
+//// [bar.js]
+export const bar = "bar";
+//// [baz.js]
+export const baz = "baz";
+//// [index.js]
+// esm format file
+import { foo } from "#/foo.js";
+import { bar } from "#/features/bar.js";
+import { baz } from "#/nested/deep/baz.js";
+foo;
+bar;
+baz;
+//// [index.mjs]
+// esm format file
+import { foo } from "#/foo.js";
+import { bar } from "#/features/bar.js";
+import { baz } from "#/nested/deep/baz.js";
+foo;
+bar;
+baz;
+//// [index.cjs]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+// cjs format file
+const foo_js_1 = require("#/foo.js");
+const bar_js_1 = require("#/features/bar.js");
+const baz_js_1 = require("#/nested/deep/baz.js");
+foo_js_1.foo;
+bar_js_1.bar;
+baz_js_1.baz;
+
+
+//// [foo.d.ts]
+export declare const foo = "foo";
+//// [bar.d.ts]
+export declare const bar = "bar";
+//// [baz.d.ts]
+export declare const baz = "baz";
+//// [index.d.ts]
+export {};
+//// [index.d.mts]
+export {};
+//// [index.d.cts]
+export {};

tests/baselines/reference/nodeModulesPackageImportsRootWildcard(module=node16).symbols

@@ -0,0 +1,74 @@
+//// [tests/cases/conformance/node/nodeModulesPackageImportsRootWildcard.ts] ////
+
+=== src/foo.ts ===
+export const foo = "foo";
+>foo : Symbol(foo, Decl(foo.ts, 0, 12))
+
+=== src/features/bar.ts ===
+export const bar = "bar";
+>bar : Symbol(bar, Decl(bar.ts, 0, 12))
+
+=== src/nested/deep/baz.ts ===
+export const baz = "baz";
+>baz : Symbol(baz, Decl(baz.ts, 0, 12))
+
+=== index.ts ===
+// esm format file
+import { foo } from "#/foo.js";
+>foo : Symbol(foo, Decl(index.ts, 1, 8))
+
+import { bar } from "#/features/bar.js";
+>bar : Symbol(bar, Decl(index.ts, 2, 8))
+
+import { baz } from "#/nested/deep/baz.js";
+>baz : Symbol(baz, Decl(index.ts, 3, 8))
+
+foo;
+>foo : Symbol(foo, Decl(index.ts, 1, 8))
+
+bar;
+>bar : Symbol(bar, Decl(index.ts, 2, 8))
+
+baz;
+>baz : Symbol(baz, Decl(index.ts, 3, 8))
+
+=== index.mts ===
+// esm format file
+import { foo } from "#/foo.js";
+>foo : Symbol(foo, Decl(index.mts, 1, 8))
+
+import { bar } from "#/features/bar.js";
+>bar : Symbol(bar, Decl(index.mts, 2, 8))
+
+import { baz } from "#/nested/deep/baz.js";
+>baz : Symbol(baz, Decl(index.mts, 3, 8))
+
+foo;
+>foo : Symbol(foo, Decl(index.mts, 1, 8))
+
+bar;
+>bar : Symbol(bar, Decl(index.mts, 2, 8))
+
+baz;
+>baz : Symbol(baz, Decl(index.mts, 3, 8))
+
+=== index.cts ===
+// cjs format file
+import { foo } from "#/foo.js";
+>foo : Symbol(foo, Decl(index.cts, 1, 8))
+
+import { bar } from "#/features/bar.js";
+>bar : Symbol(bar, Decl(index.cts, 2, 8))
+
+import { baz } from "#/nested/deep/baz.js";
+>baz : Symbol(baz, Decl(index.cts, 3, 8))
+
+foo;
+>foo : Symbol(foo, Decl(index.cts, 1, 8))
+
+bar;
+>bar : Symbol(bar, Decl(index.cts, 2, 8))
+
+baz;
+>baz : Symbol(baz, Decl(index.cts, 3, 8))
+