Continue to error on rest from generic source type

Author: ahejlsberg

src/compiler/checker.ts

@@ -4637,7 +4637,7 @@ namespace ts {
             let type: Type | undefined;
             if (pattern.kind === SyntaxKind.ObjectBindingPattern) {
                 if (declaration.dotDotDotToken) {
-                    if (parentType.flags & TypeFlags.Unknown || !isValidSpreadType(parentType)) {
+                    if (parentType.flags & TypeFlags.Unknown || !isValidSpreadType(parentType) || isGenericObjectType(parentType)) {
                         error(declaration, Diagnostics.Rest_types_may_only_be_created_from_object_types);
                         return errorType;
                     }