dart_eval runtime exception: type 'Null' is not a subtype of type '$Instance' in type cast

[HXiaoMing]

Test case:

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

void main() {
  group('set value tests', () {
    late Compiler compiler;

    setUp(() {
      compiler = Compiler();
    });

    test('Using set value', () {
      final program = compiler.compile({
        'example': {
          'main.dart': '''
            class TestClass {
              int tempValue = 0;
            }  
         
            bool main() {
              final testClass = TestClass();
              testClass.tempValue = testClass.hashCode;
              print('hashCode \${testClass.tempValue}');
              return true;
            }
          '''
        }
      });

      final runtime = Runtime.ofProgram(program);
      expect(runtime.executeLib('package:example/main.dart', 'main'), true);
    });
  });
}

Error:
package:dart_eval/src/eval/runtime/runtime.dart 832:7 Runtime.execute
package:dart_eval/src/eval/runtime/runtime.dart 810:12 Runtime.executeLib
test/set_value_test.dart 31:22 main..

dart_eval runtime exception: type 'Null' is not a subtype of type '$Instance' in type cast
#0 PushObjectProperty.run (package:dart_eval/src/eval/runtime/ops/objects.dart:276:31)
#1 Runtime.execute (package:dart_eval/src/eval/runtime/runtime.dart:823:12)
#2 Runtime.executeLib (package:dart_eval/src/eval/runtime/runtime.dart:810:12)
at main()

RUNTIME STATE

Program offset: 16
Stack sample: [L0: Instance of '$InstanceImpl', *L1: null, L2: null, L3: null, L4: null, L5: null, L6: null, L7: null, L8: null, L9: null]
Args sample: []
Call stack: [0, -1]
TRACE:
10: PushScope (F7:44, 'TestClass.tempValue (set)')
11: SetObjectPropertyImpl (L0[0] = L1)
12: Return (L1)
13: PushScope (F7:101, 'main()')
14: Call (@0)
15: PushReturnValue ()
16: PushObjectProperty (L0.C0) <<< EXCEPTION
17: PushReturnValue ()
18: SetObjectProperty (L0.tempValue = L1)
19: PushConstant (C1)

[ethanblake4]

Fixed in v0.7.9