"No published analyzer available for language version 2.14.0".

$ dart run build_runner build --delete-conflicting-outputs
[INFO] Generating build script completed, took 308ms
[WARNING] Deleted previous snapshot due to missing asset graph.
[INFO] Creating build script snapshot... completed, took 10.6s
[INFO] Building new asset graph completed, took 621ms
[INFO] Checking for unexpected pre-existing outputs. completed, took 1ms
[WARNING] json_serializable:json_serializable on bin/server.dart:
Your current `analyzer` version may not fully support your current SDK version.

Please try upgrading to the latest `analyzer` by running `flutter packages upgrade`.

Analyzer language version: 2.12.0
SDK language version: 2.14.0

If you are getting this message and have the latest analyzer please file
an issue at https://github.com/dart-lang/sdk/issues/new with the title
"No published analyzer available for language version 2.14.0".
Please search the issue tracker first and thumbs up and/or subscribe to
existing issues if present to avoid duplicates.

[SEVERE] json_serializable:json_serializable on bin/server.dart:

Bad state: Unexpected diagnostics:
/usr/local/google/home/chillers/Documents/flutter/bin/cache/dart-sdk/lib/core/int.dart:117:18 - Operator declarations must be preceded by the keyword 'operator'.
/usr/local/google/home/chillers/Documents/flutter/bin/cache/dart-sdk/lib/core/int.dart:117:18 - A function body must be provided.
/usr/local/google/home/chillers/Documents/flutter/bin/cache/dart-sdk/lib/core/int.dart:117:16 - Methods must have an explicit list of parameters.
[SEVERE] json_serializable:json_serializable on bin/server.dart: