Set use flag (#24881) (#24887)

Author: weswigham

src/services/signatureHelp.ts

@@ -343,7 +343,7 @@ namespace ts.SignatureHelp {
         return children[indexOfOpenerToken + 1];
     }
 
-    const signatureHelpNodeBuilderFlags = NodeBuilderFlags.OmitParameterModifiers | NodeBuilderFlags.IgnoreErrors;
+    const signatureHelpNodeBuilderFlags = NodeBuilderFlags.OmitParameterModifiers | NodeBuilderFlags.IgnoreErrors | NodeBuilderFlags.UseAliasDefinedOutsideCurrentScope;
     function createSignatureHelpItems(candidates: Signature[], resolvedSignature: Signature, argumentListInfo: ArgumentListInfo, typeChecker: TypeChecker): SignatureHelpItems {
         const { argumentCount, argumentsSpan: applicableSpan, invocation, argumentIndex } = argumentListInfo;
         const isTypeParameterList = argumentListInfo.kind === ArgumentListKind.TypeArguments;

tests/cases/fourslash/signatureHelpForNonlocalTypeDoesNotUseImportType.ts

@@ -0,0 +1,15 @@
+/// <reference path="fourslash.ts" />
+
+// @Filename: exporter.ts
+////export interface Thing {}
+////export const Foo: () => Thing = null as any;
+
+// @Filename: usage.ts
+////import {Foo} from "./exporter"
+////function f(p = Foo()): void {}
+////f(/*1*/
+
+verify.signatureHelp({
+    marker: "1",
+    text: "f(p?: Thing): void"
+});