add fourslash test and fix the reduction issue

microsoft · Jul 28, 2023 · 0a12f3e · 0a12f3e
1 parent 3458d37
commit 0a12f3e
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Showing 2 changed files with 11 additions and 1 deletion.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -16439,7 +16439,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function removeStringLiteralsMatchedByTemplateLiterals(types: Type[]) {
-        const templates = filter(types, t => !!(t.flags & TypeFlags.TemplateLiteral) && isPatternLiteralType(t)) as TemplateLiteralType[];
+        const templates = filter(types, t =>
+            !!(t.flags & TypeFlags.TemplateLiteral) &&
+            isPatternLiteralType(t) &&
+            (t as TemplateLiteralType).types.every(t => !(t.flags & TypeFlags.Intersection) || !areIntersectedTypesAvoidingPrimitiveReduction((t as IntersectionType).types))
+        ) as TemplateLiteralType[];
         if (templates.length) {
             let i = types.length;
             while (i > 0) {

diff --git a/tests/cases/fourslash/stringLiteralCompletionsForOpenEndedTemplateLiteralType.ts b/tests/cases/fourslash/stringLiteralCompletionsForOpenEndedTemplateLiteralType.ts
@@ -0,0 +1,6 @@
+/// <reference path="fourslash.ts" />
+
+//// function conversionTest(groupName: | "downcast" | "dataDowncast" | "editingDowncast" | `${string & {}}Downcast`) {}
+//// conversionTest("/**/");
+
+verify.completions({ marker: "", exact: ["downcast", "dataDowncast", "editingDowncast"] });