The argument type 'dynamic' can't be assigned to the parameter type 'Map<String, dynamic>' from Lint vs Pedantic

Question

I've just switched my linter in VSCode from Pedantic to Lint, and half of my app lit up. Most of it is easy to fix except for a string of Type assignment errors. The following code taken mostly from examples gives the following error:

"The argument type 'dynamic' can't be assigned to the parameter type 'Map<String, dynamic>'".

static List<Treatment> decodeData(String treatments) =>
      (jsonDecode(treatments) as List<dynamic>)
          .map<Treatment>((item) => Treatment.fromJson(item))
          .toList();

Can anyone point me in the right direction? Thanks

Answer 1

Try adding .cast<Map<String, dynamic>>() , like so:

  static List<Treatment> decodeData(String treatments) =>
      (jsonDecode(treatments) as List<dynamic>)
          .cast<Map<String, dynamic>>()
          .map<Treatment>((item) => Treatment.fromJson(item))
          .toList();

Answer 2

You can try casting it at the end

static List<Treatment> decodeData(String treatments) =>
      (jsonDecode(treatments) as List<dynamic>)
          .map<Treatment>((item) => Treatment.fromJson(item))
          .toList() as Map<String, dynamic>;