Fix decorator metadata references to type-only-imported namespaces

src/compiler/checker.ts

@@ -40348,9 +40348,14 @@ namespace ts {
             }
 
             // Resolve the symbol as a value to ensure the type can be reached at runtime during emit.
+            let isTypeOnly = false;
+            if (isQualifiedName(typeName)) {
+                const rootValueSymbol = resolveEntityName(getFirstIdentifier(typeName), SymbolFlags.Value, /*ignoreErrors*/ true, /*dontResolveAlias*/ true, location);
+                isTypeOnly = !!rootValueSymbol?.declarations?.every(isTypeOnlyImportOrExportDeclaration);
+            }
             const valueSymbol = resolveEntityName(typeName, SymbolFlags.Value, /*ignoreErrors*/ true, /*dontResolveAlias*/ true, location);
-            const isTypeOnly = valueSymbol?.declarations?.every(isTypeOnlyImportOrExportDeclaration) || false;
             const resolvedSymbol = valueSymbol && valueSymbol.flags & SymbolFlags.Alias ? resolveAlias(valueSymbol) : valueSymbol;
+            isTypeOnly ||= !!valueSymbol?.declarations?.every(isTypeOnlyImportOrExportDeclaration);
 
             // Resolve the symbol as a type so that we can provide a more useful hint for the type serializer.
             const typeSymbol = resolveEntityName(typeName, SymbolFlags.Type, /*ignoreErrors*/ true, /*dontResolveAlias*/ false, location);

tests/baselines/reference/decoratorMetadataWithTypeOnlyImport2.js

@@ -0,0 +1,53 @@
+//// [tests/cases/conformance/decorators/decoratorMetadataWithTypeOnlyImport2.ts] ////
+
+//// [services.ts]
+export namespace Services {
+  export class Service {}
+}
+
+//// [index.ts]
+import type { Services } from './services';
+
+declare const decorator: any;
+export class Main {
+  @decorator()
+  field: Services.Service;
+}
+
+
+//// [services.js]
+"use strict";
+exports.__esModule = true;
+exports.Services = void 0;
+var Services;
+(function (Services) {
+    var Service = /** @class */ (function () {
+        function Service() {
+        }
+        return Service;
+    }());
+    Services.Service = Service;
+})(Services = exports.Services || (exports.Services = {}));
+//// [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);
+};
+exports.__esModule = true;
+exports.Main = void 0;
+var Main = /** @class */ (function () {
+    function Main() {
+    }
+    __decorate([
+        decorator(),
+        __metadata("design:type", Function)
+    ], Main.prototype, "field");
+    return Main;
+}());
+exports.Main = Main;

tests/baselines/reference/decoratorMetadataWithTypeOnlyImport2.symbols

@@ -0,0 +1,27 @@
+=== tests/cases/conformance/decorators/services.ts ===
+export namespace Services {
+>Services : Symbol(Services, Decl(services.ts, 0, 0))
+
+  export class Service {}
+>Service : Symbol(Service, Decl(services.ts, 0, 27))
+}
+
+=== tests/cases/conformance/decorators/index.ts ===
+import type { Services } from './services';
+>Services : Symbol(Services, Decl(index.ts, 0, 13))
+
+declare const decorator: any;
+>decorator : Symbol(decorator, Decl(index.ts, 2, 13))
+
+export class Main {
+>Main : Symbol(Main, Decl(index.ts, 2, 29))
+
+  @decorator()
+>decorator : Symbol(decorator, Decl(index.ts, 2, 13))
+
+  field: Services.Service;
+>field : Symbol(Main.field, Decl(index.ts, 3, 19))
+>Services : Symbol(Services, Decl(index.ts, 0, 13))
+>Service : Symbol(Services.Service, Decl(services.ts, 0, 27))
+}
+

tests/baselines/reference/decoratorMetadataWithTypeOnlyImport2.types

@@ -0,0 +1,27 @@
+=== tests/cases/conformance/decorators/services.ts ===
+export namespace Services {
+>Services : typeof Services
+
+  export class Service {}
+>Service : Service
+}
+
+=== tests/cases/conformance/decorators/index.ts ===
+import type { Services } from './services';
+>Services : any
+
+declare const decorator: any;
+>decorator : any
+
+export class Main {
+>Main : Main
+
+  @decorator()
+>decorator() : any
+>decorator : any
+
+  field: Services.Service;
+>field : Services.Service
+>Services : any
+}
+

tests/cases/conformance/decorators/decoratorMetadataWithTypeOnlyImport2.ts

@@ -0,0 +1,17 @@
+// @experimentalDecorators: true
+// @emitDecoratorMetadata: true
+
+
+// @filename: services.ts
+export namespace Services {
+  export class Service {}
+}
+
+// @filename: index.ts
+import type { Services } from './services';
+
+declare const decorator: any;
+export class Main {
+  @decorator()
+  field: Services.Service;
+}