Compiler Crashing With Unsupported Operation in Dart 2.14, 2.15; Compiles Fine in Dart 2.12

[chgibb]

Working in a closed-source monorepo of Flutter projects. Trying to upgrade the monorepo from Flutter 2.0.6 (Dart 2.12) to Flutter 2.5.3 (Dart 2.14), one of the projects is suddenly failing to compile. These failures appear to be reproducible consistently on Flutter dev channel (Flutter 2.6.0-11.0.pre, Dart 2.15.0-116.0.dev), Flutter beta channel (Flutter 2.8.0-3.2.pre, Dart 2.15.0-268.18.beta) and Flutter stable channel (Flutter 2.5.3, Dart 2.14.4). This error does not exist (and everything compiles fine) on Flutter 2.0.6 (Dart 2.12.3). It is unexpected to suddenly encounter an issue like this on the stable channel.

Flutter 2.5.3 (Dart 2.14.4)

Flutter 2.5.3 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 18116933e7 (6 weeks ago) • 2021-10-15 10:46:35 -0700
Engine • revision d3ea636dc5
Tools • Dart 2.14.4
Building without sound null safety
For more information see https://dart.dev/null-safety/unsound-null-safety

Unhandled exception:
Crash when compiling <removed file name>,
at character offset 9003:
Unsupported operation: moretop(InterfaceType(Object?), FutureOrType(FutureOr<Object?>%))
#0      StandardBounds.moretop (package:kernel/src/standard_bounds.dart:124:5)
#1      StandardBounds.getNullabilityAwareStandardLowerBoundInternal (package:kernel/src/standard_bounds.dart:276:42)
#2      TypeSchemaStandardBounds.getNullabilityAwareStandardLowerBoundInternal (package:front_end/src/fasta/type_inference/standard_bounds.dart:27:18)
#3      StandardBounds._getNullabilityAwareStandardLowerBound (package:kernel/src/standard_bounds.dart:264:12)
#4      StandardBounds.getStandardLowerBound (package:kernel/src/standard_bounds.dart:252:14)
#5      TypeSchemaEnvironment.addUpperBound (package:front_end/src/fasta/type_inference/type_schema_environment.dart:121:9)
#6      TypeSchemaEnvironment._inferTypeParameterFromAll (package:front_end/src/fasta/type_inference/type_schema_environment.dart:539:7)
#7      TypeSchemaEnvironment.inferTypeFromConstraints (package:front_end/src/fasta/type_inference/type_schema_environment.dart:352:28)
#8      TypeSchemaEnvironment.inferGenericFunctionOrType (package:front_end/src/fasta/type_inference/type_schema_environment.dart:288:5)
#9      TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2395:29)
#10     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:12)
#11     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3098:40)
#12     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3612:20)
#13     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2817:21)
#14     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4555:20)
#15     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1962:27)
#16     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#17     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5819:61)
#18     ReturnStatement.accept (package:kernel/ast.dart:9468:43)
#19     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#20     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2663:43)
#21     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1294:21)
#22     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1325:9)
#23     FunctionExpression.accept1 (package:kernel/ast.dart:7888:9)
#24     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#25     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#26     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2334:42)
#27     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:12)
#28     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3098:40)
#29     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3612:20)
#30     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2817:21)
#31     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4555:20)
#32     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1962:27)
#33     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#34     InferenceVisitor.visitNullAwareMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2885:59)
#35     NullAwareMethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:1208:20)
#36     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1962:27)
#37     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#38     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5819:61)
#39     ReturnStatement.accept (package:kernel/ast.dart:9468:43)
#40     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#41     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2663:43)
#42     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1294:21)
#43     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1325:9)
#44     FunctionExpression.accept1 (package:kernel/ast.dart:7888:9)
#45     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#46     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#47     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2286:44)
#48     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:12)
#49     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3098:40)
#50     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3612:20)
#51     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2817:21)
#52     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4555:20)
#53     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1962:27)
#54     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#55     InferenceVisitor.visitAwaitExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:454:56)
#56     AwaitExpression.accept1 (package:kernel/ast.dart:7825:9)
#57     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#58     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#59     InferenceVisitor.visitExpressionStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:901:49)
#60     ExpressionStatement.accept (package:kernel/ast.dart:8433:43)
#61     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#62     InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:468:20)
#63     InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:489:31)
#64     Block.accept (package:kernel/ast.dart:8489:43)
#65     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#66     InferenceVisitor.visitIfStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:1432:52)
#67     IfStatement.accept (package:kernel/ast.dart:9393:43)
#68     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#69     InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:468:20)
#70     InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:489:31)
#71     Block.accept (package:kernel/ast.dart:8489:43)
#72     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#73     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2663:43)
#74     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1294:21)
#75     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1325:9)
#76     FunctionExpression.accept1 (package:kernel/ast.dart:7888:9)
#77     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#78     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#79     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2334:42)
#80     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:12)
#81     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3098:40)
#82     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3612:20)
#83     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2817:21)
#84     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4555:20)
#85     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1962:27)
#86     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#87     InferenceVisitor.visitNullAwareMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2885:59)
#88     NullAwareMethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:1208:20)
#89     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1962:27)
#90     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#91     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5819:61)
#92     ReturnStatement.accept (package:kernel/ast.dart:9468:43)
#93     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#94     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2663:43)
#95     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1294:21)
#96     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1325:9)
#97     FunctionExpression.accept1 (package:kernel/ast.dart:7888:9)
#98     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#99     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#100    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2286:44)
#101    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:12)
#102    TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3098:40)
#103    TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3612:20)
#104    InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2817:21)
#105    MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4555:20)
#106    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1962:27)
#107    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#108    InferenceVisitor.visitAwaitExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:454:56)
#109    AwaitExpression.accept1 (package:kernel/ast.dart:7825:9)
#110    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#111    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#112    InferenceVisitor.visitExpressionStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:901:49)
#113    ExpressionStatement.accept (package:kernel/ast.dart:8433:43)
#114    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#115    InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:468:20)
#116    InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:489:31)
#117    Block.accept (package:kernel/ast.dart:8489:43)
#118    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#119    TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2663:43)
#120    InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1294:21)
#121    InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1325:9)
#122    FunctionExpression.accept1 (package:kernel/ast.dart:7888:9)
#123    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#124    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#125    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2334:42)
#126    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:12)
#127    InferenceVisitor.visitConstructorInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:624:49)
#128    ConstructorInvocation.accept1 (package:kernel/ast.dart:5999:9)
#129    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#130    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#131    InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5819:61)
#132    ReturnStatement.accept (package:kernel/ast.dart:9468:43)
#133    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#134    TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2663:43)
#135    InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1294:21)
#136    InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1325:9)
#137    FunctionExpression.accept1 (package:kernel/ast.dart:7888:9)
#138    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#139    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#140    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2286:44)
#141    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:12)
#142    InferenceVisitor.visitStaticInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:5971:49)
#143    StaticInvocation.accept1 (package:kernel/ast.dart:5909:9)
#144    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#145    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#146    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2334:42)
#147    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:12)
#148    InferenceVisitor.visitConstructorInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:624:49)
#149    ConstructorInvocation.accept1 (package:kernel/ast.dart:5999:9)
#150    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1964:27)
#151    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1998:40)
#152    InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5819:61)
#153    ReturnStatement.accept (package:kernel/ast.dart:9468:43)
#154    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#155    InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:468:20)
#156    InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:489:31)
#157    Block.accept (package:kernel/ast.dart:8489:43)
#158    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3889:24)
#159    TypeInferrerImpl.inferFunctionBody (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:39)
#160    BodyBuilder.finishFunction (package:front_end/src/fasta/kernel/body_builder.dart:1034:43)
#161    DietListener.listenerFinishFunction (package:front_end/src/fasta/source/diet_listener.dart:958:14)
#162    DietListener.buildFunctionBody (package:front_end/src/fasta/source/diet_listener.dart:996:7)
#163    DietListener._endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:712:5)
#164    DietListener.endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:662:5)
#165    Parser.parseMethod (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4054:20)
#166    Parser.parseClassOrMixinOrExtensionMemberImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3778:15)
#167    Parser.parseClassOrMixinOrExtensionBody (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3437:15)
#168    Parser.parseClass (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2000:13)
#169    Parser.parseClassOrNamedMixinApplication (package:_fe_analyzer_shared/src/parser/parser_impl.dart:1958:14)
#170    Parser.parseTopLevelKeywordDeclaration (package:_fe_analyzer_shared/src/parser/parser_impl.dart:581:14)
#171    Parser.parseTopLevelDeclarationImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:477:14)
#172    Parser.parseUnit (package:_fe_analyzer_shared/src/parser/parser_impl.dart:357:15)
#173    SourceLoader.buildBody (package:front_end/src/fasta/source/source_loader.dart:496:14)
<asynchronous suspension>
#174    Loader.buildBodies (package:front_end/src/fasta/loader.dart:296:9)
<asynchronous suspension>
#175    KernelTarget.buildComponent.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:366:7)
<asynchronous suspension>
#176    withCrashReporting (package:front_end/src/fasta/crash.dart:121:12)
<asynchronous suspension>
#177    generateKernelInternal.<anonymous closure> (package:front_end/src/kernel_generator_impl.dart:163:19)
<asynchronous suspension>
#178    withCrashReporting (package:front_end/src/fasta/crash.dart:121:12)
<asynchronous suspension>
#179    kernelForProgramInternal.<anonymous closure> (package:front_end/src/api_prototype/kernel_generator.dart:59:29)
<asynchronous suspension>
#180    kernelForProgramInternal (package:front_end/src/api_prototype/kernel_generator.dart:58:10)
<asynchronous suspension>
#181    kernelForProgram (package:front_end/src/api_prototype/kernel_generator.dart:50:11)
<asynchronous suspension>
#182    compileToKernel (package:vm/kernel_front_end.dart:360:22)
<asynchronous suspension>
#183    FrontendCompiler.compile (package:frontend_server/frontend_server.dart:540:17)
<asynchronous suspension>
#184    starter (package:flutter_frontend_server/server.dart:85:12)
<asynchronous suspension>
#185    main (file:///opt/s/w/ir/cache/builder/src/flutter/flutter_frontend_server/bin/starter.dart:13:24)
<asynchronous suspension>


#0      DietListener.buildFunctionBody (package:front_end/src/fasta/source/diet_listener.dart:1001:7)
#1      DietListener._endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:712:5)
#2      DietListener.endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:662:5)
#3      Parser.parseMethod (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4054:20)
#4      Parser.parseClassOrMixinOrExtensionMemberImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3778:15)
#5      Parser.parseClassOrMixinOrExtensionBody (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3437:15)
#6      Parser.parseClass (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2000:13)
#7      Parser.parseClassOrNamedMixinApplication (package:_fe_analyzer_shared/src/parser/parser_impl.dart:1958:14)
#8      Parser.parseTopLevelKeywordDeclaration (package:_fe_analyzer_shared/src/parser/parser_impl.dart:581:14)
#9      Parser.parseTopLevelDeclarationImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:477:14)
#10     Parser.parseUnit (package:_fe_analyzer_shared/src/parser/parser_impl.dart:357:15)
#11     SourceLoader.buildBody (package:front_end/src/fasta/source/source_loader.dart:496:14)
<asynchronous suspension>
#12     Loader.buildBodies (package:front_end/src/fasta/loader.dart:296:9)
<asynchronous suspension>
#13     KernelTarget.buildComponent.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:366:7)
<asynchronous suspension>
#14     withCrashReporting (package:front_end/src/fasta/crash.dart:121:12)
<asynchronous suspension>
#15     generateKernelInternal.<anonymous closure> (package:front_end/src/kernel_generator_impl.dart:163:19)
<asynchronous suspension>
#16     withCrashReporting (package:front_end/src/fasta/crash.dart:121:12)
<asynchronous suspension>
#17     kernelForProgramInternal.<anonymous closure> (package:front_end/src/api_prototype/kernel_generator.dart:59:29)
<asynchronous suspension>
#18     kernelForProgramInternal (package:front_end/src/api_prototype/kernel_generator.dart:58:10)
<asynchronous suspension>
#19     kernelForProgram (package:front_end/src/api_prototype/kernel_generator.dart:50:11)
<asynchronous suspension>
#20     compileToKernel (package:vm/kernel_front_end.dart:360:22)
<asynchronous suspension>
#21     FrontendCompiler.compile (package:frontend_server/frontend_server.dart:540:17)
<asynchronous suspension>
#22     starter (package:flutter_frontend_server/server.dart:85:12)
<asynchronous suspension>
#23     main (file:///opt/s/w/ir/cache/builder/src/flutter/flutter_frontend_server/bin/starter.dart:13:24)
<asynchronous suspension>



FAILURE: Build failed with an exception.

* Where:
Script '/Users/chgibb/Downloads/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 1005

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

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 17s
Running Gradle task 'assembleDebug'...                             18.2s
Gradle task assembleDebug failed with exit code 1

Flutter 2.6.0-11.0.pre (Dart 2.15.0-116.0.dev)

Flutter 2.6.0-11.0.pre • channel dev • https://github.com/flutter/flutter.git
Framework • revision 4b330ddbed (2 months ago) • 2021-09-16 17:29:58 -0700
Engine • revision 5b81c6d615
Tools • Dart 2.15.0 (build 2.15.0-116.0.dev)
Building without sound null safety
For more information see https://dart.dev/null-safety/unsound-null-safety

Unhandled exception:
Crash when compiling <removed file name>,
at character offset 9003:
Unsupported operation: moretop(InterfaceType(Object?), FutureOrType(FutureOr<Object?>%))
#0      StandardBounds.moretop (package:kernel/src/standard_bounds.dart:124:5)
#1      StandardBounds.getNullabilityAwareStandardLowerBoundInternal (package:kernel/src/standard_bounds.dart:280:42)
#2      TypeSchemaStandardBounds.getNullabilityAwareStandardLowerBoundInternal (package:front_end/src/fasta/type_inference/standard_bounds.dart:27:18)
#3      StandardBounds._getNullabilityAwareStandardLowerBound (package:kernel/src/standard_bounds.dart:264:12)
#4      StandardBounds.getStandardLowerBound (package:kernel/src/standard_bounds.dart:252:14)
#5      TypeSchemaEnvironment.addUpperBound (package:front_end/src/fasta/type_inference/type_schema_environment.dart:123:9)
#6      TypeSchemaEnvironment._inferTypeParameterFromAll (package:front_end/src/fasta/type_inference/type_schema_environment.dart:541:7)
#7      TypeSchemaEnvironment.inferTypeFromConstraints (package:front_end/src/fasta/type_inference/type_schema_environment.dart:354:28)
#8      TypeSchemaEnvironment.inferGenericFunctionOrType (package:front_end/src/fasta/type_inference/type_schema_environment.dart:290:5)
#9      TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2444:29)
#10     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2133:12)
#11     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3148:40)
#12     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3681:20)
#13     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2830:21)
#14     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4605:20)
#15     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2006:27)
#16     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#17     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5806:61)
#18     ReturnStatement.accept (package:kernel/ast.dart:9651:43)
#19     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#20     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2713:43)
#21     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1314:21)
#22     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1345:9)
#23     FunctionExpression.accept1 (package:kernel/ast.dart:8071:9)
#24     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#25     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#26     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2379:42)
#27     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2133:12)
#28     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3148:40)
#29     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3681:20)
#30     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2830:21)
#31     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4605:20)
#32     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2006:27)
#33     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#34     InferenceVisitor.visitNullAwareMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2898:59)
#35     NullAwareMethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:1241:20)
#36     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2006:27)
#37     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#38     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5806:61)
#39     ReturnStatement.accept (package:kernel/ast.dart:9651:43)
#40     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#41     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2713:43)
#42     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1314:21)
#43     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1345:9)
#44     FunctionExpression.accept1 (package:kernel/ast.dart:8071:9)
#45     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#46     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#47     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2331:44)
#48     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2133:12)
#49     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3148:40)
#50     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3681:20)
#51     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2830:21)
#52     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4605:20)
#53     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2006:27)
#54     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#55     InferenceVisitor.visitAwaitExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:473:56)
#56     AwaitExpression.accept1 (package:kernel/ast.dart:8008:9)
#57     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#58     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#59     InferenceVisitor.visitExpressionStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:921:49)
#60     ExpressionStatement.accept (package:kernel/ast.dart:8616:43)
#61     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#62     InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:487:20)
#63     InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:508:31)
#64     Block.accept (package:kernel/ast.dart:8672:43)
#65     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#66     InferenceVisitor.visitIfStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:1445:52)
#67     IfStatement.accept (package:kernel/ast.dart:9576:43)
#68     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#69     InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:487:20)
#70     InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:508:31)
#71     Block.accept (package:kernel/ast.dart:8672:43)
#72     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#73     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2713:43)
#74     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1314:21)
#75     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1345:9)
#76     FunctionExpression.accept1 (package:kernel/ast.dart:8071:9)
#77     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#78     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#79     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2379:42)
#80     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2133:12)
#81     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3148:40)
#82     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3681:20)
#83     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2830:21)
#84     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4605:20)
#85     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2006:27)
#86     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#87     InferenceVisitor.visitNullAwareMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2898:59)
#88     NullAwareMethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:1241:20)
#89     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2006:27)
#90     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#91     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5806:61)
#92     ReturnStatement.accept (package:kernel/ast.dart:9651:43)
#93     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#94     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2713:43)
#95     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1314:21)
#96     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1345:9)
#97     FunctionExpression.accept1 (package:kernel/ast.dart:8071:9)
#98     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#99     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#100    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2331:44)
#101    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2133:12)
#102    TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3148:40)
#103    TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3681:20)
#104    InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2830:21)
#105    MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4605:20)
#106    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2006:27)
#107    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#108    InferenceVisitor.visitAwaitExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:473:56)
#109    AwaitExpression.accept1 (package:kernel/ast.dart:8008:9)
#110    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#111    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#112    InferenceVisitor.visitExpressionStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:921:49)
#113    ExpressionStatement.accept (package:kernel/ast.dart:8616:43)
#114    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#115    InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:487:20)
#116    InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:508:31)
#117    Block.accept (package:kernel/ast.dart:8672:43)
#118    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#119    TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2713:43)
#120    InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1314:21)
#121    InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1345:9)
#122    FunctionExpression.accept1 (package:kernel/ast.dart:8071:9)
#123    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#124    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#125    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2379:42)
#126    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2133:12)
#127    InferenceVisitor.visitConstructorInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:643:49)
#128    ConstructorInvocation.accept1 (package:kernel/ast.dart:6171:9)
#129    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#130    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#131    InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5806:61)
#132    ReturnStatement.accept (package:kernel/ast.dart:9651:43)
#133    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#134    TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2713:43)
#135    InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1314:21)
#136    InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1345:9)
#137    FunctionExpression.accept1 (package:kernel/ast.dart:8071:9)
#138    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#139    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#140    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2331:44)
#141    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2133:12)
#142    InferenceVisitor.visitStaticInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:5958:49)
#143    StaticInvocation.accept1 (package:kernel/ast.dart:6081:9)
#144    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#145    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#146    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2379:42)
#147    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2133:12)
#148    InferenceVisitor.visitConstructorInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:643:49)
#149    ConstructorInvocation.accept1 (package:kernel/ast.dart:6171:9)
#150    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2008:27)
#151    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2043:40)
#152    InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5806:61)
#153    ReturnStatement.accept (package:kernel/ast.dart:9651:43)
#154    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#155    InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:487:20)
#156    InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:508:31)
#157    Block.accept (package:kernel/ast.dart:8672:43)
#158    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:3958:24)
#159    TypeInferrerImpl.inferFunctionBody (package:front_end/src/fasta/type_inference/type_inferrer.dart:2088:39)
#160    BodyBuilder.finishFunction (package:front_end/src/fasta/kernel/body_builder.dart:1122:43)
#161    DietListener.buildFunctionBody (package:front_end/src/fasta/source/diet_listener.dart:992:19)
#162    DietListener._endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:721:5)
#163    DietListener.endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:671:5)
#164    Parser.parseMethod (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4161:20)
#165    Parser.parseClassOrMixinOrExtensionMemberImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3882:15)
#166    Parser.parseClassOrMixinOrExtensionBody (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3539:15)
#167    Parser.parseClass (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2042:13)
#168    Parser.parseClassOrNamedMixinApplication (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2000:14)
#169    Parser.parseTopLevelKeywordDeclaration (package:_fe_analyzer_shared/src/parser/parser_impl.dart:601:14)
#170    Parser.parseTopLevelDeclarationImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:497:14)
#171    Parser.parseUnit (package:_fe_analyzer_shared/src/parser/parser_impl.dart:377:15)
#172    SourceLoader.buildBody (package:front_end/src/fasta/source/source_loader.dart:500:14)
<asynchronous suspension>
#173    Loader.buildBodies (package:front_end/src/fasta/loader.dart:296:9)
<asynchronous suspension>
#174    KernelTarget.buildComponent.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:371:7)
<asynchronous suspension>
#175    withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#176    generateKernelInternal.<anonymous closure> (package:front_end/src/kernel_generator_impl.dart:163:19)
<asynchronous suspension>
#177    withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#178    kernelForProgramInternal.<anonymous closure> (package:front_end/src/api_prototype/kernel_generator.dart:59:29)
<asynchronous suspension>
#179    kernelForProgramInternal (package:front_end/src/api_prototype/kernel_generator.dart:58:10)
<asynchronous suspension>
#180    kernelForProgram (package:front_end/src/api_prototype/kernel_generator.dart:50:11)
<asynchronous suspension>
#181    compileToKernel (package:vm/kernel_front_end.dart:360:22)
<asynchronous suspension>
#182    FrontendCompiler.compile (package:frontend_server/frontend_server.dart:541:17)
<asynchronous suspension>
#183    starter (package:flutter_frontend_server/server.dart:85:12)
<asynchronous suspension>
#184    main (file:///opt/s/w/ir/cache/builder/src/flutter/flutter_frontend_server/bin/starter.dart:13:24)
<asynchronous suspension>


#0      DietListener.buildFunctionBody (package:front_end/src/fasta/source/diet_listener.dart:996:7)
#1      DietListener._endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:721:5)
#2      DietListener.endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:671:5)
#3      Parser.parseMethod (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4161:20)
#4      Parser.parseClassOrMixinOrExtensionMemberImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3882:15)
#5      Parser.parseClassOrMixinOrExtensionBody (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3539:15)
#6      Parser.parseClass (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2042:13)
#7      Parser.parseClassOrNamedMixinApplication (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2000:14)
#8      Parser.parseTopLevelKeywordDeclaration (package:_fe_analyzer_shared/src/parser/parser_impl.dart:601:14)
#9      Parser.parseTopLevelDeclarationImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:497:14)
#10     Parser.parseUnit (package:_fe_analyzer_shared/src/parser/parser_impl.dart:377:15)
#11     SourceLoader.buildBody (package:front_end/src/fasta/source/source_loader.dart:500:14)
<asynchronous suspension>
#12     Loader.buildBodies (package:front_end/src/fasta/loader.dart:296:9)
<asynchronous suspension>
#13     KernelTarget.buildComponent.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:371:7)
<asynchronous suspension>
#14     withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#15     generateKernelInternal.<anonymous closure> (package:front_end/src/kernel_generator_impl.dart:163:19)
<asynchronous suspension>
#16     withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#17     kernelForProgramInternal.<anonymous closure> (package:front_end/src/api_prototype/kernel_generator.dart:59:29)
<asynchronous suspension>
#18     kernelForProgramInternal (package:front_end/src/api_prototype/kernel_generator.dart:58:10)
<asynchronous suspension>
#19     kernelForProgram (package:front_end/src/api_prototype/kernel_generator.dart:50:11)
<asynchronous suspension>
#20     compileToKernel (package:vm/kernel_front_end.dart:360:22)
<asynchronous suspension>
#21     FrontendCompiler.compile (package:frontend_server/frontend_server.dart:541:17)
<asynchronous suspension>
#22     starter (package:flutter_frontend_server/server.dart:85:12)
<asynchronous suspension>
#23     main (file:///opt/s/w/ir/cache/builder/src/flutter/flutter_frontend_server/bin/starter.dart:13:24)
<asynchronous suspension>



FAILURE: Build failed with an exception.

* Where:
Script '/Users/chgibb/Downloads/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 1005

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

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 18s
Running Gradle task 'assembleDebug'...                             18.9s
Gradle task assembleDebug failed with exit code 1

Flutter 2.8.0-3.2.pre (Dart 2.15.0-268.18.beta)

Flutter 2.8.0-3.2.pre • channel beta • https://github.com/flutter/flutter.git
Framework • revision 2901cd7208 (11 days ago) • 2021-11-18 11:15:09 -0800
Engine • revision bcc2b7f12c
Tools • Dart 2.15.0 (build 2.15.0-268.18.beta)

Building without sound null safety
For more information see https://dart.dev/null-safety/unsound-null-safety

Unhandled exception:
Crash when compiling <removed file name>,
at character offset 9003:
Unsupported operation: moretop(InterfaceType(Object?), FutureOrType(FutureOr<Object?>%))
#0      StandardBounds.moretop (package:kernel/src/standard_bounds.dart:124:5)
#1      StandardBounds.getNullabilityAwareStandardLowerBoundInternal (package:kernel/src/standard_bounds.dart:280:42)
#2      TypeSchemaStandardBounds.getNullabilityAwareStandardLowerBoundInternal (package:front_end/src/fasta/type_inference/standard_bounds.dart:27:18)
#3      StandardBounds._getNullabilityAwareStandardLowerBound (package:kernel/src/standard_bounds.dart:264:12)
#4      StandardBounds.getStandardLowerBound (package:kernel/src/standard_bounds.dart:252:14)
#5      TypeSchemaEnvironment.addUpperBound (package:front_end/src/fasta/type_inference/type_schema_environment.dart:123:9)
#6      TypeSchemaEnvironment._inferTypeParameterFromAll (package:front_end/src/fasta/type_inference/type_schema_environment.dart:541:7)
#7      TypeSchemaEnvironment.inferTypeFromConstraints (package:front_end/src/fasta/type_inference/type_schema_environment.dart:354:28)
#8      TypeSchemaEnvironment.inferGenericFunctionOrType (package:front_end/src/fasta/type_inference/type_schema_environment.dart:290:5)
#9      TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2520:29)
#10     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2114:12)
#11     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3226:40)
#12     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3761:20)
#13     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2893:21)
#14     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4611:20)
#15     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1987:27)
#16     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#17     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5909:61)
#18     ReturnStatement.accept (package:kernel/ast.dart:9869:43)
#19     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#20     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2791:43)
#21     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1370:21)
#22     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1401:9)
#23     FunctionExpression.accept1 (package:kernel/ast.dart:8288:9)
#24     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#25     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#26     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2427:44)
#27     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2114:12)
#28     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3226:40)
#29     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3761:20)
#30     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2893:21)
#31     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4611:20)
#32     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1987:27)
#33     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#34     InferenceVisitor.visitNullAwareMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2975:59)
#35     NullAwareMethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:1247:20)
#36     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1987:27)
#37     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#38     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5909:61)
#39     ReturnStatement.accept (package:kernel/ast.dart:9869:43)
#40     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#41     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2791:43)
#42     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1370:21)
#43     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1401:9)
#44     FunctionExpression.accept1 (package:kernel/ast.dart:8288:9)
#45     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#46     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#47     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2385:46)
#48     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2114:12)
#49     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3226:40)
#50     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3761:20)
#51     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2893:21)
#52     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4611:20)
#53     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1987:27)
#54     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#55     InferenceVisitor.visitAwaitExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:528:56)
#56     AwaitExpression.accept1 (package:kernel/ast.dart:8225:9)
#57     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#58     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#59     InferenceVisitor.visitExpressionStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:976:49)
#60     ExpressionStatement.accept (package:kernel/ast.dart:8834:43)
#61     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#62     InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:542:20)
#63     InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:563:31)
#64     Block.accept (package:kernel/ast.dart:8890:43)
#65     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#66     InferenceVisitor.visitIfStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:1504:52)
#67     IfStatement.accept (package:kernel/ast.dart:9794:43)
#68     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#69     InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:542:20)
#70     InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:563:31)
#71     Block.accept (package:kernel/ast.dart:8890:43)
#72     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#73     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2791:43)
#74     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1370:21)
#75     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1401:9)
#76     FunctionExpression.accept1 (package:kernel/ast.dart:8288:9)
#77     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#78     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#79     TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2427:44)
#80     TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2114:12)
#81     TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3226:40)
#82     TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3761:20)
#83     InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2893:21)
#84     MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4611:20)
#85     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1987:27)
#86     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#87     InferenceVisitor.visitNullAwareMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2975:59)
#88     NullAwareMethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:1247:20)
#89     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1987:27)
#90     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#91     InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5909:61)
#92     ReturnStatement.accept (package:kernel/ast.dart:9869:43)
#93     TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#94     TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2791:43)
#95     InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1370:21)
#96     InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1401:9)
#97     FunctionExpression.accept1 (package:kernel/ast.dart:8288:9)
#98     TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#99     TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#100    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2385:46)
#101    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2114:12)
#102    TypeInferrerImpl._inferInstanceMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3226:40)
#103    TypeInferrerImpl.inferMethodInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:3761:20)
#104    InferenceVisitor.visitMethodInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:2893:21)
#105    MethodInvocation.acceptInference (package:front_end/src/fasta/kernel/internal_ast.dart:4611:20)
#106    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1987:27)
#107    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#108    InferenceVisitor.visitAwaitExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:528:56)
#109    AwaitExpression.accept1 (package:kernel/ast.dart:8225:9)
#110    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#111    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#112    InferenceVisitor.visitExpressionStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:976:49)
#113    ExpressionStatement.accept (package:kernel/ast.dart:8834:43)
#114    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#115    InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:542:20)
#116    InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:563:31)
#117    Block.accept (package:kernel/ast.dart:8890:43)
#118    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#119    TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2791:43)
#120    InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1370:21)
#121    InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1401:9)
#122    FunctionExpression.accept1 (package:kernel/ast.dart:8288:9)
#123    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#124    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#125    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2427:44)
#126    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2114:12)
#127    InferenceVisitor.visitConstructorInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:698:49)
#128    ConstructorInvocation.accept1 (package:kernel/ast.dart:6388:9)
#129    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#130    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#131    InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5909:61)
#132    ReturnStatement.accept (package:kernel/ast.dart:9869:43)
#133    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#134    TypeInferrerImpl.inferLocalFunction (package:front_end/src/fasta/type_inference/type_inferrer.dart:2791:43)
#135    InferenceVisitor.visitFunctionNode (package:front_end/src/fasta/kernel/inference_visitor.dart:1370:21)
#136    InferenceVisitor.visitFunctionExpression (package:front_end/src/fasta/kernel/inference_visitor.dart:1401:9)
#137    FunctionExpression.accept1 (package:kernel/ast.dart:8288:9)
#138    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#139    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#140    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2385:46)
#141    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2114:12)
#142    InferenceVisitor.visitStaticInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:6061:49)
#143    StaticInvocation.accept1 (package:kernel/ast.dart:6298:9)
#144    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#145    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#146    TypeInferrerImpl._inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2427:44)
#147    TypeInferrerImpl.inferInvocation (package:front_end/src/fasta/type_inference/type_inferrer.dart:2114:12)
#148    InferenceVisitor.visitConstructorInvocation (package:front_end/src/fasta/kernel/inference_visitor.dart:698:49)
#149    ConstructorInvocation.accept1 (package:kernel/ast.dart:6388:9)
#150    TypeInferrerImpl._inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:1989:27)
#151    TypeInferrerImpl.inferExpression (package:front_end/src/fasta/type_inference/type_inferrer.dart:2024:40)
#152    InferenceVisitor.visitReturnStatement (package:front_end/src/fasta/kernel/inference_visitor.dart:5909:61)
#153    ReturnStatement.accept (package:kernel/ast.dart:9869:43)
#154    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#155    InferenceVisitor._visitStatements (package:front_end/src/fasta/kernel/inference_visitor.dart:542:20)
#156    InferenceVisitor.visitBlock (package:front_end/src/fasta/kernel/inference_visitor.dart:563:31)
#157    Block.accept (package:kernel/ast.dart:8890:43)
#158    TypeInferrerImpl.inferStatement (package:front_end/src/fasta/type_inference/type_inferrer.dart:4038:24)
#159    TypeInferrerImpl.inferFunctionBody (package:front_end/src/fasta/type_inference/type_inferrer.dart:2069:39)
#160    BodyBuilder.finishFunction (package:front_end/src/fasta/kernel/body_builder.dart:1134:43)
#161    DietListener.buildFunctionBody (package:front_end/src/fasta/source/diet_listener.dart:991:19)
#162    DietListener._endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:720:5)
#163    DietListener.endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:670:5)
#164    Parser.parseMethod (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4162:20)
#165    Parser.parseClassOrMixinOrExtensionMemberImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3883:15)
#166    Parser.parseClassOrMixinOrExtensionBody (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3540:15)
#167    Parser.parseClass (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2042:13)
#168    Parser.parseClassOrNamedMixinApplication (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2000:14)
#169    Parser.parseTopLevelKeywordDeclaration (package:_fe_analyzer_shared/src/parser/parser_impl.dart:601:14)
#170    Parser.parseTopLevelDeclarationImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:497:14)
#171    Parser.parseUnit (package:_fe_analyzer_shared/src/parser/parser_impl.dart:377:15)
#172    SourceLoader.buildBody (package:front_end/src/fasta/source/source_loader.dart:960:14)
<asynchronous suspension>
#173    SourceLoader.buildBodies (package:front_end/src/fasta/source/source_loader.dart:522:9)
<asynchronous suspension>
#174    KernelTarget.buildComponent.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:457:7)
<asynchronous suspension>
#175    withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#176    generateKernelInternal.<anonymous closure> (package:front_end/src/kernel_generator_impl.dart:162:19)
<asynchronous suspension>
#177    withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#178    kernelForProgramInternal.<anonymous closure> (package:front_end/src/api_prototype/kernel_generator.dart:59:29)
<asynchronous suspension>
#179    kernelForProgramInternal (package:front_end/src/api_prototype/kernel_generator.dart:58:10)
<asynchronous suspension>
#180    kernelForProgram (package:front_end/src/api_prototype/kernel_generator.dart:50:11)
<asynchronous suspension>
#181    compileToKernel (package:vm/kernel_front_end.dart:360:22)
<asynchronous suspension>
#182    FrontendCompiler.compile (package:frontend_server/frontend_server.dart:541:17)
<asynchronous suspension>
#183    starter (package:flutter_frontend_server/server.dart:85:12)
<asynchronous suspension>
#184    main (file:///opt/s/w/ir/cache/builder/src/flutter/flutter_frontend_server/bin/starter.dart:13:24)
<asynchronous suspension>


#0      DietListener.buildFunctionBody (package:front_end/src/fasta/source/diet_listener.dart:995:7)
#1      DietListener._endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:720:5)
#2      DietListener.endClassMethod (package:front_end/src/fasta/source/diet_listener.dart:670:5)
#3      Parser.parseMethod (package:_fe_analyzer_shared/src/parser/parser_impl.dart:4162:20)
#4      Parser.parseClassOrMixinOrExtensionMemberImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3883:15)
#5      Parser.parseClassOrMixinOrExtensionBody (package:_fe_analyzer_shared/src/parser/parser_impl.dart:3540:15)
#6      Parser.parseClass (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2042:13)
#7      Parser.parseClassOrNamedMixinApplication (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2000:14)
#8      Parser.parseTopLevelKeywordDeclaration (package:_fe_analyzer_shared/src/parser/parser_impl.dart:601:14)
#9      Parser.parseTopLevelDeclarationImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:497:14)
#10     Parser.parseUnit (package:_fe_analyzer_shared/src/parser/parser_impl.dart:377:15)
#11     SourceLoader.buildBody (package:front_end/src/fasta/source/source_loader.dart:960:14)
<asynchronous suspension>
#12     SourceLoader.buildBodies (package:front_end/src/fasta/source/source_loader.dart:522:9)
<asynchronous suspension>
#13     KernelTarget.buildComponent.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:457:7)
<asynchronous suspension>
#14     withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#15     generateKernelInternal.<anonymous closure> (package:front_end/src/kernel_generator_impl.dart:162:19)
<asynchronous suspension>
#16     withCrashReporting (package:front_end/src/fasta/crash.dart:122:12)
<asynchronous suspension>
#17     kernelForProgramInternal.<anonymous closure> (package:front_end/src/api_prototype/kernel_generator.dart:59:29)
<asynchronous suspension>
#18     kernelForProgramInternal (package:front_end/src/api_prototype/kernel_generator.dart:58:10)
<asynchronous suspension>
#19     kernelForProgram (package:front_end/src/api_prototype/kernel_generator.dart:50:11)
<asynchronous suspension>
#20     compileToKernel (package:vm/kernel_front_end.dart:360:22)
<asynchronous suspension>
#21     FrontendCompiler.compile (package:frontend_server/frontend_server.dart:541:17)
<asynchronous suspension>
#22     starter (package:flutter_frontend_server/server.dart:85:12)
<asynchronous suspension>
#23     main (file:///opt/s/w/ir/cache/builder/src/flutter/flutter_frontend_server/bin/starter.dart:13:24)
<asynchronous suspension>



FAILURE: Build failed with an exception.

* Where:
Script '/Users/chgibb/Downloads/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 1070

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

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 21s
Running Gradle task 'assembleDebug'...                             22.3s
Gradle task assembleDebug failed with exit code 1

As this is a closed source project, is there a way to share more information that might aid in debugging in a non-public way?

If this is the wrong place to file this issue or more information is needed, please advise.

[chgibb]

This continues to be a blocker to adoption of Flutter 2.5 for us. Is there any update? Is there more information I should provide?

[chloestefantsova]

It's possible that this issue is fixed after 7d8d3bb and 3d27f5c have landed. @chgibb can you check if you still experience it?

[chgibb]

@chloestefantsova I am no longer employed by the company that uses the repository in question.

[chloestefantsova]

Ok, I'm closing the issue. Please reopen if the issue still surfaces.