diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1b3084f9cbd..b2f34987a8d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -10239,7 +10239,7 @@ namespace ts {
             const objectFlags = getObjectFlags(type);
             return !!(type.flags & TypeFlags.TypeVariable ||
                 objectFlags & ObjectFlags.Reference && forEach((<TypeReference>type).typeArguments, couldContainTypeVariables) ||
-                objectFlags & ObjectFlags.Anonymous && type.symbol && type.symbol.flags & (SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class) ||
+                objectFlags & ObjectFlags.Anonymous && type.symbol && type.symbol.flags & (SymbolFlags.Function | SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class) ||
                 objectFlags & ObjectFlags.Mapped ||
                 type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeVariables(<UnionOrIntersectionType>type));
         }