diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9ca8b60d36a..4493b9e00a3 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -23451,7 +23451,7 @@ namespace ts {
         }
 
         function getUniqueTypeParameters(context: InferenceContext, typeParameters: ReadonlyArray<TypeParameter>): ReadonlyArray<TypeParameter> {
-            let result: TypeParameter[] = [];
+            const result: TypeParameter[] = [];
             let oldTypeParameters: TypeParameter[] | undefined;
             let newTypeParameters: TypeParameter[] | undefined;
             for (const tp of typeParameters) {