Nullable dart bug

readme.md

Nullable dart bug

Created with <3 with dartpad.dev.

main.dart

void main() {
  String? x = test(null);
  String y = test("a");
}

A test<A extends Object?>(A a) =>
  switch((A,a.runtimeType)){
    (String,Null) => (){print("found miscasted nullable string"); return a;}(),    
    (String,_) => (){print("found non-null string"); return a;}(),
    (String?,_) => (){print("found nullable string"); return a;}(),
    (Type(),_) => (){print("failed to find nullable string for $A, "
                           "which"
                           " ${A is String? "is":"isn't"} String, "
                           "${A is String? "is":"isn't"} String?, "
                           " ${null is A ? "is": "isn't"} null," ); return a;}(),
  };