Switch to getApparentType

Author: rbuckton

src/compiler/checker.ts

@@ -16281,18 +16281,10 @@ namespace ts {
             }
         }
 
-        function isTypeOrConstraintAnyOrNever(type: Type) {
-            while (type.flags & TypeFlags.TypeVariable) {
-                const constraint = getConstraintOfTypeVariable(<TypeVariable>type);
-                if (!constraint) break;
-                type = getWidenedType(constraint);
-            }
-            return (type.flags & (TypeFlags.Any | TypeFlags.Never)) !== 0;
-        }
-
         function checkNonThenableType(type: Type, location?: Node, message?: DiagnosticMessage): Type {
             type = getWidenedType(type);
-            if (!isTypeOrConstraintAnyOrNever(type) && isTypeAssignableTo(type, getGlobalThenableType())) {
+            const apparentType = getApparentType(type);
+            if ((apparentType.flags & (TypeFlags.Any | TypeFlags.Never)) === 0 && isTypeAssignableTo(type, getGlobalThenableType())) {
                 if (location) {
                     if (!message) {
                         message = Diagnostics.Operand_for_await_does_not_have_a_valid_callable_then_member;