Don't skip markLinkedReferences on ambient properties (#59325)

src/compiler/checker.ts

@@ -29704,8 +29704,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         if (!canCollectSymbolAliasAccessabilityData) {
             return;
         }
-        if (location.flags & NodeFlags.Ambient) {
-            return; // References within types and declaration files are never going to contribute to retaining a JS import
+        if (location.flags & NodeFlags.Ambient && !isPropertySignature(location) && !isPropertyDeclaration(location)) {
+            // References within types and declaration files are never going to contribute to retaining a JS import,
+            // except for properties (which can be decorated).
+            return;
         }
         switch (hint) {
             case ReferenceHint.Identifier:

tests/baselines/reference/decoratorMetadataElidedImportOnDeclare(module=commonjs).js

@@ -0,0 +1,36 @@
+//// [tests/cases/compiler/decoratorMetadataElidedImportOnDeclare.ts] ////
+
+//// [observable.d.ts]
+export declare class Observable<T> {}
+
+//// [index.ts]
+import { Observable } from './observable';
+
+function whatever(a: any, b: any) {}
+
+class Test {
+    @whatever
+    declare prop: Observable<string>;
+}
+
+
+//// [index.js]
+"use strict";
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var __metadata = (this && this.__metadata) || function (k, v) {
+    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const observable_1 = require("./observable");
+function whatever(a, b) { }
+class Test {
+}
+__decorate([
+    whatever,
+    __metadata("design:type", observable_1.Observable)
+], Test.prototype, "prop", void 0);

tests/baselines/reference/decoratorMetadataElidedImportOnDeclare(module=commonjs).symbols

@@ -0,0 +1,27 @@
+//// [tests/cases/compiler/decoratorMetadataElidedImportOnDeclare.ts] ////
+
+=== observable.d.ts ===
+export declare class Observable<T> {}
+>Observable : Symbol(Observable, Decl(observable.d.ts, 0, 0))
+>T : Symbol(T, Decl(observable.d.ts, 0, 32))
+
+=== index.ts ===
+import { Observable } from './observable';
+>Observable : Symbol(Observable, Decl(index.ts, 0, 8))
+
+function whatever(a: any, b: any) {}
+>whatever : Symbol(whatever, Decl(index.ts, 0, 42))
+>a : Symbol(a, Decl(index.ts, 2, 18))
+>b : Symbol(b, Decl(index.ts, 2, 25))
+
+class Test {
+>Test : Symbol(Test, Decl(index.ts, 2, 36))
+
+    @whatever
+>whatever : Symbol(whatever, Decl(index.ts, 0, 42))
+
+    declare prop: Observable<string>;
+>prop : Symbol(Test.prop, Decl(index.ts, 4, 12))
+>Observable : Symbol(Observable, Decl(index.ts, 0, 8))
+}
+

tests/baselines/reference/decoratorMetadataElidedImportOnDeclare(module=commonjs).types

@@ -0,0 +1,31 @@
+//// [tests/cases/compiler/decoratorMetadataElidedImportOnDeclare.ts] ////
+
+=== observable.d.ts ===
+export declare class Observable<T> {}
+>Observable : Observable<T>
+>           : ^^^^^^^^^^^^^
+
+=== index.ts ===
+import { Observable } from './observable';
+>Observable : typeof Observable
+>           : ^^^^^^^^^^^^^^^^^
+
+function whatever(a: any, b: any) {}
+>whatever : (a: any, b: any) => void
+>         : ^ ^^   ^^ ^^   ^^^^^^^^^
+>a : any
+>b : any
+
+class Test {
+>Test : Test
+>     : ^^^^
+
+    @whatever
+>whatever : (a: any, b: any) => void
+>         : ^ ^^   ^^ ^^   ^^^^^^^^^
+
+    declare prop: Observable<string>;
+>prop : Observable<string>
+>     : ^^^^^^^^^^^^^^^^^^
+}
+

tests/baselines/reference/decoratorMetadataElidedImportOnDeclare(module=esnext).js

@@ -0,0 +1,34 @@
+//// [tests/cases/compiler/decoratorMetadataElidedImportOnDeclare.ts] ////
+
+//// [observable.d.ts]
+export declare class Observable<T> {}
+
+//// [index.ts]
+import { Observable } from './observable';
+
+function whatever(a: any, b: any) {}
+
+class Test {
+    @whatever
+    declare prop: Observable<string>;
+}
+
+
+//// [index.js]
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var __metadata = (this && this.__metadata) || function (k, v) {
+    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+};
+import { Observable } from './observable';
+function whatever(a, b) { }
+class Test {
+}
+__decorate([
+    whatever,
+    __metadata("design:type", Observable)
+], Test.prototype, "prop", void 0);

tests/baselines/reference/decoratorMetadataElidedImportOnDeclare(module=esnext).symbols

@@ -0,0 +1,27 @@
+//// [tests/cases/compiler/decoratorMetadataElidedImportOnDeclare.ts] ////
+
+=== observable.d.ts ===
+export declare class Observable<T> {}
+>Observable : Symbol(Observable, Decl(observable.d.ts, 0, 0))
+>T : Symbol(T, Decl(observable.d.ts, 0, 32))
+
+=== index.ts ===
+import { Observable } from './observable';
+>Observable : Symbol(Observable, Decl(index.ts, 0, 8))
+
+function whatever(a: any, b: any) {}
+>whatever : Symbol(whatever, Decl(index.ts, 0, 42))
+>a : Symbol(a, Decl(index.ts, 2, 18))
+>b : Symbol(b, Decl(index.ts, 2, 25))
+
+class Test {
+>Test : Symbol(Test, Decl(index.ts, 2, 36))
+
+    @whatever
+>whatever : Symbol(whatever, Decl(index.ts, 0, 42))
+
+    declare prop: Observable<string>;
+>prop : Symbol(Test.prop, Decl(index.ts, 4, 12))
+>Observable : Symbol(Observable, Decl(index.ts, 0, 8))
+}
+

tests/baselines/reference/decoratorMetadataElidedImportOnDeclare(module=esnext).types

@@ -0,0 +1,31 @@
+//// [tests/cases/compiler/decoratorMetadataElidedImportOnDeclare.ts] ////
+
+=== observable.d.ts ===
+export declare class Observable<T> {}
+>Observable : Observable<T>
+>           : ^^^^^^^^^^^^^
+
+=== index.ts ===
+import { Observable } from './observable';
+>Observable : typeof Observable
+>           : ^^^^^^^^^^^^^^^^^
+
+function whatever(a: any, b: any) {}
+>whatever : (a: any, b: any) => void
+>         : ^ ^^   ^^ ^^   ^^^^^^^^^
+>a : any
+>b : any
+
+class Test {
+>Test : Test
+>     : ^^^^
+
+    @whatever
+>whatever : (a: any, b: any) => void
+>         : ^ ^^   ^^ ^^   ^^^^^^^^^
+
+    declare prop: Observable<string>;
+>prop : Observable<string>
+>     : ^^^^^^^^^^^^^^^^^^
+}
+

tests/cases/compiler/decoratorMetadataElidedImportOnDeclare.ts

@@ -0,0 +1,18 @@
+// @target: es2020
+// @module: commonjs, esnext
+// @strict: true
+// @experimentalDecorators: true
+// @emitDecoratorMetadata: true
+
+// @filename: observable.d.ts
+export declare class Observable<T> {}
+
+// @filename: index.ts
+import { Observable } from './observable';
+
+function whatever(a: any, b: any) {}
+
+class Test {
+    @whatever
+    declare prop: Observable<string>;
+}