Crash when compiling card.dart: type 'int' is not a subtype of type 'Constructor' in type cast

[lukehutch]

I got the following spurious Dart compiler crash while compiling a Flutter app. (I can't reproduce this, and I don't know what caused it.)

Unhandled exception:
Crash when compiling file:///opt/flutter/packages/flutter/lib/src/material/card.dart at character offset 5744:
card.dart:1
type 'int' is not a subtype of type 'Constructor' in type cast

#0      Reference.asConstructor (package:kernel/canonical_name.dart:533:17)
#1      ConstructorInvocation.target (package:kernel/ast.dart:6982:45)
#2      InferenceVisitorImpl.visitConstructorInvocation (package:front_end/src/fasta/type_inference/inference_visitor.dart:889:27)
#3      ConstructorInvocation.accept1 (package:kernel/ast.dart:7003:9)
#4      InferenceVisitorImpl._inferExpression (package:front_end/src/fasta/type_inference/inference_visitor.dart:181:27)
#5      InferenceVisitorImpl.inferExpression (package:front_end/src/fasta/type_inference/inference_visitor.dart:216:40)
#6      InferenceVisitorImpl.visitConditionalExpression (package:front_end/src/fasta/type_inference/inference_visitor.dart:873:9)
#7      ConditionalExpression.accept1 (package:kernel/ast.dart:7304:9)
#8      InferenceVisitorImpl._inferExpression (package:front_end/src/fasta/type_inference/inference_visitor.dart:181:27)

#9      InferenceVisitorImpl.inferExpression (package:front_end/src/fasta/type_inference/inference_visitor.dart:216:40)
#10     InferenceVisitorImpl.visitVariableDeclaration (package:front_end/src/fasta/type_inference/inference_visitor.dart:7935:11)
#11     VariableDeclaration.accept (package:kernel/ast.dart:11226:43)
#12     InferenceVisitorImpl.inferStatement (package:front_end/src/fasta/type_inference/inference_visitor.dart:159:26)
#13     InferenceVisitorImpl._visitStatements (package:front_end/src/fasta/type_inference/inference_visitor.dart:741:50)
#14     InferenceVisitorImpl.visitBlock (package:front_end/src/fasta/type_inference/inference_visitor.dart:762:31)
#15     Block.accept (package:kernel/ast.dart:9638:43)
#16     InferenceVisitorImpl.inferStatement (package:front_end/src/fasta/type_inference/inference_visitor.dart:159:26)
#17     TypeInferrerImpl.inferFunctionBody (package:front_end/src/fasta/type_inference/type_inferrer.dart:187:17)
#18     BodyBuilder.finishFunction (package:front_end/src/fasta/kernel/body_builder.dart:1306:43)
#19     DietListener.buildFunctionBody (package:front_end/src/fasta/source/diet_listener.dart:1112:19)
#20     DietListener._endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:750:5)
#21     DietListener.endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:689:5)
#22     Parser.parseMethod (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4718:20)
#23     Parser.parseClassOrMixinOrExtensionOrEnumMemberImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4435:15)
#24     Parser.parseClassOrMixinOrExtensionBody (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4080:15)
#25     Parser.parseClass (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2532:13)
#26     Parser.parseClassOrNamedMixinApplication (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2490:14)
#27     Parser.parseTopLevelKeywordDeclaration (package:_fe_analyzer_shared/src/parser/parser_impl.dart:628:14)
#28     Parser.parseTopLevelDeclarationImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:524:14)
#29     Parser.parseUnit (package:_fe_analyzer_shared/src/parser/parser_impl.dart:404:15)
#30     SourceLoader.buildBody (package:front_end/src/fasta/source/source_loader.dart:1260:12)

<asynchronous suspension>
#31     SourceLoader.buildBodies (package:front_end/src/fasta/source/source_loader.dart:673:7)
<asynchronous suspension>
#32     KernelTarget.buildComponent.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:612:7)
<asynchronous suspension>
#33     withCrashReporting (package:front_end/src/fasta/crash.dart:136:12)
<asynchronous suspension>
#34     IncrementalCompiler.computeDelta.<anonymous closure> (package:front_end/src/fasta/incremental_compiler.dart:413:23)
<asynchronous suspension>
#35     IncrementalCompiler.compile (package:vm/incremental_compiler.dart:68:50)
<asynchronous suspension>
#36     FrontendCompiler.compile (package:frontend_server/frontend_server.dart:574:11)
<asynchronous suspension>
#37     starter (package:frontend_server/starter.dart:99:12)
<asynchronous suspension>
#38     main (file:///b/s/w/ir/x/w/sdk/pkg/frontend_server/bin/frontend_server_starter.dart:13:14)
<asynchronous suspension>
2

Target kernel_snapshot failed: Exception
2

FAILURE: Build failed with an exception.
* Where:
Script '/opt/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 1151

* What went wrong:
Execution failed for task ':app:compileFlutterBuildDebug'.
> Process 'command '/opt/flutter/bin/flutter'' finished with non-zero exit value 1

• Dart SDK Version (dart --version): 2.19.2
• Whether you are using Windows, MacOSX, or Linux (if applicable): Linux
• Whether you are using Chrome, Safari, Firefox, Edge (if applicable): Chrome

[mraleph]

Thanks for reporting this. int can never appear in this place, so it is likely a JIT problem. That being said: unlikely that we can figure this out without a reproduction.

/cc @alexmarkov @mkustermann