Setting static setter: Null check operator used on a null value

[fischerscode]

It seems like setting static setters / fields doesn't work.
The following test fails with Null check operator used on a null value during compiler.compile.

When removing assign(), the dart_eval code compiles. And the static getter works just fine.

Stacktrace

Null check operator used on a null value
package:dart_eval/src/eval/compiler/reference.dart 101:71              IdentifierReference.setValue
package:dart_eval/src/eval/compiler/expression/assignment.dart 19:14   compileAssignmentExpression
package:dart_eval/src/eval/compiler/expression/expression.dart 34:12   compileExpression
package:dart_eval/src/eval/compiler/expression/expression.dart 106:12  compileExpressionAndDiscardResult
package:dart_eval/src/eval/compiler/statement/statement.dart 26:15     compileStatement
package:dart_eval/src/eval/compiler/statement/block.dart 19:20         compileBlock
package:dart_eval/src/eval/compiler/declaration/function.dart 84:14    compileFunctionDeclaration
package:dart_eval/src/eval/compiler/declaration/declaration.dart 24:5  compileDeclaration
package:dart_eval/src/eval/compiler/compiler.dart 492:11               Compiler.compileSources.<fn>.<fn>
dart:collection                                                        _LinkedHashMapMixin.forEach
package:dart_eval/src/eval/compiler/compiler.dart 481:15               Compiler.compileSources.<fn>
dart:collection                                                        _LinkedHashMapMixin.forEach
package:dart_eval/src/eval/compiler/compiler.dart 477:32               Compiler.compileSources
package:dart_eval/src/eval/compiler/compiler.dart 163:12               Compiler.compile
test\eval\bug_test.dart 191:42                                         main.<fn>

Entire test file:

import 'package:dart_eval/dart_eval.dart';
import 'package:test/test.dart';

import 'package:dart_eval/dart_eval_bridge.dart';
import 'package:dart_eval/dart_eval_extensions.dart';
import 'package:dart_eval/stdlib/core.dart';

class TestClass {
  static int value = 0;
}

class $TestClass implements $Instance {
  $TestClass.wrap(this.$value);

  static final $type = BridgeTypeSpec(
    'package:my_package/file.dart',
    'TestClass',
  );

  static final $declaration = BridgeClassDef(
    BridgeClassType(
      $type.ref,
      $extends: BridgeTypeRef(BridgeTypeSpec(
        'dart:core',
        'Object',
      )),
      $implements: [],
      $with: [],
      isAbstract: false,
    ),
    constructors: {
      '': BridgeConstructorDef(
        BridgeFunctionDef(
          returns: $type.ref.annotate,
          params: [],
          namedParams: [],
          generics: {},
        ),
        isFactory: false,
      )
    },
    methods: {},
    getters: {
      'value': BridgeMethodDef(
        BridgeFunctionDef(
          returns: BridgeTypeRef(
            BridgeTypeSpec(
              'dart:core',
              'int',
            ),
            [],
          ).annotate,
          params: [],
          namedParams: [],
          generics: {},
        ),
        isStatic: true,
      ),
    },
    setters: {
      'value': BridgeMethodDef(
        BridgeFunctionDef(
          returns: CoreTypes.voidType.ref.annotate,
          params: [
            '_value'.param(BridgeTypeRef(
              BridgeTypeSpec(
                'dart:core',
                'int',
              ),
              [],
            ).annotate)
          ],
          namedParams: [],
          generics: {},
        ),
        isStatic: true,
      ),
    },
    bridge: false,
    wrap: true,
  );

  @override
  final TestClass $value;

  late final $Instance _$superWrapper = $Object($value);

  static void configureForCompile(BridgeDeclarationRegistry registry) {
    registry.defineBridgeClass($declaration);
  }

  static void configureForRuntime(Runtime runtime) {
    runtime.registerBridgeFunc(
      'package:my_package/file.dart',
      'TestClass.value*g',
      $TestClass.$g$value,
    );
    runtime.registerBridgeFunc(
      'package:my_package/file.dart',
      'TestClass.value*s',
      $TestClass.$s$value,
    );
    runtime.registerBridgeFunc(
      'package:my_package/file.dart',
      'TestClass.',
      $TestClass.$new,
    );
  }

  @override
  get $reified => $value;

  static $Value? $new(
    Runtime runtime,
    $Value? target,
    List<$Value?> args,
  ) {
    return $TestClass.wrap(TestClass());
  }

  @override
  $Value? $getProperty(
    Runtime runtime,
    String identifier,
  ) {
    switch (identifier) {
      case 'value':
        return $int(TestClass.value);
      default:
        return _$superWrapper.$getProperty(
          runtime,
          identifier,
        );
    }
  }

  @override
  void $setProperty(
    Runtime runtime,
    String identifier,
    $Value value,
  ) {
    switch (identifier) {
      case 'value':
        TestClass.value = ($Value $) {
          final $$ = ($ as dynamic);
          return $$ is! int ? ($.$reified as int) : $$;
        }(value);
      default:
        _$superWrapper.$setProperty(
          runtime,
          identifier,
          value,
        );
    }
  }

  @override
  int $getRuntimeType(Runtime runtime) {
    return runtime.lookupType($type);
  }

  static $Value? $g$value(
    Runtime runtime,
    $Value? target,
    List<$Value?> args,
  ) {
    return $int(TestClass.value);
  }

  static $Value? $s$value(
    Runtime runtime,
    $Value? target,
    List<$Value?> args,
  ) {
    TestClass.value = ($Value $) {
      final $$ = ($ as dynamic);
      return $$ is! int ? ($.$reified as int) : $$;
    }(args[0]!);
    return null;
  }
}

void main() {
  late Runtime runtime;

  setUpAll(() {
    var compiler = Compiler();
    $TestClass.configureForCompile(compiler);

    runtime = Runtime.ofProgram(compiler.compile({
      'eval_builder': {
        'main.dart': '''
      import 'package:my_package/file.dart';
      int value() {
        return TestClass.value;
      }
      void assign() {
        TestClass.value = 123;
      }
    '''
      }
    }));
    $TestClass.configureForRuntime(runtime);
  });

  test('value', () {
    TestClass.value = 987;
    expect(
        runtime.executeLib('package:eval_builder/main.dart', 'value', []), 987);
  });
  test('assign', () {
    TestClass.value = 0;
    runtime.executeLib('package:eval_builder/main.dart', 'assign', []);
    expect(TestClass.value, 123);
  }, skip: true);
}

void main() {
  late Runtime runtime;

  setUpAll(() {
    var compiler = Compiler();
    $TestClass.configureForCompile(compiler);

    runtime = Runtime.ofProgram(compiler.compile({
      'eval_builder': {
        'main.dart': '''
      import 'package:my_package/file.dart';
      int value() {
        return TestClass.value;
      }
      void assign() {
        TestClass.value = 123;
      }
    '''
      }
    }));
    $TestClass.configureForRuntime(runtime);
  });

  test('value', () {
    TestClass.value = 987;
    expect(
        runtime.executeLib('package:eval_builder/main.dart', 'value', []), 987);
  });
  test('assign', () {
    TestClass.value = 0;
    runtime.executeLib('package:eval_builder/main.dart', 'assign', []);
    expect(TestClass.value, 123);
  }, skip: true);
}

I've run into this while working on a code builder. But I'm pretty confident that this is not related to me doing something wrong.