Unsupported operation: serialization of generic DartType: UnknownType(?) (UnknownType)

[datayeah]

Tried to compile my flutter app which always worked since the last update.

name and version of operating system:
MacOS Mojave 10.14.4 (18E226)

• the Dart SDK build number (2.9.0-edge.69aba23371ffb12caf596e29dab0d52f74a591e7), and

The compiler crashed: Unsupported operation: serialization of generic DartType: UnknownType(?) (UnknownType)
#0 BinaryPrinter.defaultDartType (package:kernel/binary/ast_to_binary.dart:2229:5)
#1 UnknownType.accept (package:front_end/src/fasta/type_inference/type_schema.dart:82:14)
#2 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#3 BinaryPrinter.writeNodeList (package:kernel/binary/ast_to_binary.dart:291:7)
#4 BinaryPrinter.visitInterfaceType (package:kernel/binary/ast_to_binary.dart:2067:7)
#5 InterfaceType.accept (package:kernel/ast.dart:7504:42)
#6 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#7 BinaryPrinter.visitFutureOrType (package:kernel/binary/ast_to_binary.dart:2088:5)
#8 FutureOrType.accept (package:kernel/ast.dart:7903:42)
#9 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#10 BinaryPrinter.visitAsExpression (package:kernel/binary/ast_to_binary.dart:1614:5)
#11 AsExpression.accept (package:kernel/ast.dart:4913:44)
#12 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#13 BinaryPrinter.writeOptionalNode (package:kernel/binary/ast_to_binary.dart:474:7)
#14 BinaryPrinter.visitReturnStatement (package:kernel/binary/ast_to_binary.dart:1942:5)
#15 ReturnStatement.accept (package:kernel/ast.dart:6491:43)
#16 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#17 BinaryPrinter.writeNodeList (package:kernel/binary/ast_to_binary.dart:291:7)
#18 BinaryPrinter.visitBlock (package:kernel/binary/ast_to_binary.dart:1801:5)
#19 Block.accept (package:kernel/ast.dart:5823:43)
#20 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#21 BinaryPrinter.writeOptionalNode (package:kernel/binary/ast_to_binary.dart:474:7)
#22 BinaryPrinter.visitFunctionNode (package:kernel/binary/ast_to_binary.dart:1325:5)
#23 FunctionNode.accept (package:kernel/ast.dart:2909:38)
#24 BinaryPrinter.writeFunctionNode (package:kernel/binary/ast_to_binary.dart:388:10)
#25 BinaryPrinter.visitFunctionExpression (package:kernel/binary/ast_to_binary.dart:1740:5)
#26 FunctionExpression.accept (package:kernel/ast.dart:5535:44)
#27 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#28 BinaryPrinter.visitNamedExpression (package:kernel/binary/ast_to_binary.dart:1501:5)
#29 NamedExpression.accept (package:kernel/ast.dart:3813:38)
#30 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#31 BinaryPrinter.writeNodeList (package:kernel/binary/ast_to_binary.dart:291:7)
#32 BinaryPrinter.visitArguments (package:kernel/binary/ast_to_binary.dart:1495:5)
#33 Arguments.accept (package:kernel/ast.dart:3753:38)
#34 BinaryPrinter.writeArgumentsNode (package:kernel/binary/ast_to_binary.dart:395:10)
#35 BinaryPrinter.visitConstructorInvocation (package:kernel/binary/ast_to_binary.dart:1487:5)
#36 ConstructorInvocation.accept (package:kernel/ast.dart:4154:44)
#37 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#38 BinaryPrinter.visitNamedExpression (package:kernel/binary/ast_to_binary.dart:1501:5)
#39 NamedExpression.accept (package:kernel/ast.dart:3813:38)
#40 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#41 BinaryPrinter.writeNodeList (package:kernel/binary/ast_to_binary.dart:291:7)
#42 BinaryPrinter.visitArguments (package:kernel/binary/ast_to_binary.dart:1495:5)
#43 Arguments.accept (package:kernel/ast.dart:3753:38)
#44 BinaryPrinter.writeArgumentsNode (package:kernel/binary/ast_to_binary.dart:395:10)
#45 BinaryPrinter.visitConstructorInvocation (package:kernel/binary/ast_to_binary.dart:1487:5)
#46 ConstructorInvocation.accept (package:kernel/ast.dart:4154:44)
#47 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#48 BinaryPrinter.writeNodeList (package:kernel/binary/ast_to_binary.dart:291:7)
#49 BinaryPrinter.visitListLiteral (package:kernel/binary/ast_to_binary.dart:1703:5)
#50 ListLiteral.accept (package:kernel/ast.dart:5292:44)
#51 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#52 BinaryPrinter.visitNamedExpression (package:kernel/binary/ast_to_binary.dart:1501:5)
#53 NamedExpression.accept (package:kernel/ast.dart:3813:38)
#54 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#55 BinaryPrinter.writeNodeList (package:kernel/binary/ast_to_binary.dart:291:7)
#56 BinaryPrinter.visitArguments (package:kernel/binary/ast_to_binary.dart:1495:5)
#57 Arguments.accept (package:kernel/ast.dart:3753:38)
#58 BinaryPrinter.writeArgumentsNode (package:kernel/binary/ast_to_binary.dart:395:10)
#59 BinaryPrinter.visitConstructorInvocation (package:kernel/binary/ast_to_binary.dart:1487:5)
#60 ConstructorInvocation.accept (package:kernel/ast.dart:4154:44)
#61 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#62 BinaryPrinter.visitNamedExpression (package:kernel/binary/ast_to_binary.dart:1501:5)
#63 NamedExpression.accept (package:kernel/ast.dart:3813:38)
#64 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#65 BinaryPrinter.writeNodeList (package:kernel/binary/ast_to_binary.dart:291:7)
#66 BinaryPrinter.visitArguments (package:kernel/binary/ast_to_binary.dart:1495:5)
#67 Arguments.accept (package:kernel/ast.dart:3753:38)
#68 BinaryPrinter.writeArgumentsNode (package:kernel/binary/ast_to_binary.dart:395:10)
#69 BinaryPrinter.visitConstructorInvocation (package:kernel/binary/ast_to_binary.dart:1487:5)
#70 ConstructorInvocation.accept (package:kernel/ast.dart:4154:44)
#71 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#72 BinaryPrinter.writeOptionalNode (package:kernel/binary/ast_to_binary.dart:474:7)
#73 BinaryPrinter.visitReturnStatement (package:kernel/binary/ast_to_binary.dart:1942:5)
#74 ReturnStatement.accept (package:kernel/ast.dart:6491:43)
#75 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#76 BinaryPrinter.writeNodeList (package:kernel/binary/ast_to_binary.dart:291:7)
#77 BinaryPrinter.visitBlock (package:kernel/binary/ast_to_binary.dart:1801:5)
#78 Block.accept (package:kernel/ast.dart:5823:43)
#79 BinaryPrinter.writeNode (package:kernel/binary/ast_to_binary.dart:381:10)
#80 BinaryPrinter.writeOptionalNode (package:kernel/binary/ast_to_binary.dart:474:7)
#81 BinaryPrinter.visitFunctionNode (package:kernel/binary/ast_to_binary.dart:1325:5)
#82 FunctionNode.accept (package:kernel/ast.dart:2909:38)
#83 BinaryPrinter.writeFunctionNode (package:kernel/binary/ast_to_binary.dart:388:10)
#84 BinaryPrinter.writeOptionalFunctionNode (package:kernel/binary/ast_to_binary.dart:483:7)
#85 BinaryPrinter.visitProcedure (package:kernel/binary/ast_to_binary.dart:1201:5)
#86 Procedure.accept (package:kernel/ast.dart:2400:40)
#87 BinaryPrinter.writeProcedureNode (package:kernel/binary/ast_to_binary.dart:409:10)
#88 BinaryPrinter.writeProcedureNodeList (package:kernel/binary/ast_to_binary.dart:300:7)
#89 BinaryPrinter.visitClass (package:kernel/binary/ast_to_binary.dart:1129:5)
#90 Class.accept (package:kernel/ast.dart:1379:38)
#91 BinaryPrinter.writeClassNode (package:kernel/binary/ast_to_binary.dart:423:10)
#92 BinaryPrinter.writeClassNodeList (package:kernel/binary/ast_to_binary.dart:318:7)
#93 BinaryPrinter.visitLibrary (package:kernel/binary/ast_to_binary.dart:959:5)
#94 Library.accept (package:kernel/ast.dart:607:38)
#95 BinaryPrinter.writeLibraryNode (package:kernel/binary/ast_to_binary.dart:402:10)
#96 BinaryPrinter.writeLibraries (package:kernel/binary/ast_to_binary.dart:708:9)
#97 BinaryPrinter.writeComponentFile. (package:kernel/binary/ast_to_binary.dart:551:7)
#98 Timeline.timeSync (dart:developer/timeline.dart:163:22)
#99 BinaryPrinter.writeComponentFile (package:kernel/binary/ast_to_binary.dart:535:14)
#100 KernelLoaderTask.load.. (package:compiler/src/kernel/loader.dart:198:19)
#101 CompilerTask.measureSubtask (package:compiler/src/common/tasks.dart:179:35)
#102 KernelLoaderTask.load. (package:compiler/src/kernel/loader.dart:191:9)

#103 KernelLoaderTask.load. (package:compiler/src/kernel/loader.dart)
#104 CompilerTask.measure (package:compiler/src/common/tasks.dart:64:51)
#105 KernelLoaderTask.load (package:compiler/src/kernel/loader.dart:60:12)
#106 Compiler.runInternal (package:compiler/src/compiler.dart:238:48)
#107 Compiler.run.. (package:compiler/src/compiler.dart:212:38)
#108 new Future.sync (dart:async/future.dart:223:31)
#109 Compiler.run. (package:compiler/src/compiler.dart:212:20)
#110 CompilerTask.measureSubtask (package:compiler/src/common/tasks.dart:179:35)
#111 Compiler.run (package:compiler/src/compiler.dart:209:41)
#112 CompilerImpl.run.. (package:compiler/src/apiimpl.dart:91:22)
#113 _RootZone.runUnary (dart:async/zone.dart:1450:54)
#114 _FutureListener.handleValue (dart:async/future_impl.dart:143:18)
#115 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:696:45)
#116 Future._propagateToListeners (dart:async/future_impl.dart:725:32)
#117 Future._completeWithValue (dart:async/future_impl.dart:529:5)
#118 Future._asyncCompleteWithValue. (dart:async/future_impl.dart:567:7)
#119 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
#120 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
#121 _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:118:13)
#122 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:169:5)

[sigmundch]

@johnniwinther - this may be a CFE issue. This is happening under the --cfe-only flag, so it is serializing the dill immediately after invoking the CFE.

[chloestefantsova]

Thanks for the report, @datayeah. I couldn't reproduce the bug based on the stack trace. Could you provide a small snippet causing the crash, stripped off any app-specific information?

It would also be helpful to know if the crash surfaces on Dart SDK commit hash 8d4d3a3 (the one before the likely culprit commit).

[johnniwinther]

I have a repro:

import 'dart:async';

class Class<T> {
  Class({FutureOr<List<T>> Function() a});
}

dynamic method() => null;

main() {
  Class(a: () async => method());
}

[datayeah]

It's a quite big project i am working on for some time now, so i am unable to (or unsure how to) isolate the part thats causing the crash. Thanks for adding an example, @johnniwinther!

[chloestefantsova]

Thanks for the repro @johnniwinther. I'm working on a fix in CL 154322.

[Shiba-Kar]

Unsupported operation: serialization of generic DartType: UnknownType(?) (UnknownType)
Conformed same here !!

[johnniwinther]

@Shiba-Kar Which version of Dart are you running?

[Shiba-Kar]

@Shiba-Kar Which version of Dart are you running?

2.9.0

[johnniwinther]

This fix is not in '2.9.0' but is in the pipeline for a future release.

@Shiba-Kar Are you blocked by this or do you have a work-around?

[Shiba-Kar]

This fix is not in '2.9.0' but is in the pipeline for a future release.

@Shiba-Kar Are you blocked by this or do you have a work-around?

For the time being I have downgraded to 1.17.5 flutter

[a-siva]

This was fixed in the Dart tree at ac4de98, I don't believe the fix is in Flutter 1.20 which has Dart version 2.9

[pcsosinski]

should we consider this for a CP to 2.9? @franklinyow

[franklinyow]

@pcsosinski 2.9 mean a hotfix release?
@johnniwinther