Fasta crashes on this generic function type code

[scheglov]

typedef Foo<S> = S Function<T>(T x);
int foo<T>(T x) => 3;
Foo<int> bar() => foo;
void test1() {
  bar()<String>("hello");
}

class A {
  Foo<int> f;
  void test() {
    f<String>("hello");
  }
}

It work fine in Analyzer.

  NoSuchMethodError: The method 'accept' was called on null.
  Receiver: null
  Tried calling: accept(Instance of '_InnerTypeSubstitutor')
  #0      Object._noSuchMethod (dart:core-patch/object_patch.dart:42)
  #1      Object.noSuchMethod (dart:core-patch/object_patch.dart:46)
  #2      _TypeSubstitutor.visit (package:kernel/type_algebra.dart:370:41)
  #3      _InnerTypeSubstitutor.freshTypeParameter (package:kernel/type_algebra.dart:324:19)
  #4      MappedListIterable.elementAt (dart:_internal/iterable.dart:413)
  #5      ListIterable.toList (dart:_internal/iterable.dart:218)
  #6      _TypeSubstitutor.freshTypeParameters (package:kernel/type_algebra.dart:396:47)
  #7      _TypeSubstitutor.visitFunctionType (package:kernel/type_algebra.dart:417:32)
  #8      FunctionType.accept (package:kernel/ast.dart:4486:34)
  #9      _TypeSubstitutor.visit (package:kernel/type_algebra.dart:370:41)
  #10     Substitution.substituteType (package:kernel/type_algebra.dart:235:53)
  #11     substitute (package:kernel/type_algebra.dart:19:45)
  #12     KernelFunctionTypeAliasBuilder.buildTypesWithBuiltArguments (package:front_end/src/fasta/kernel/kernel_function_type_alias_builder.dart:92:12)
  #13     KernelFunctionTypeAliasBuilder.buildType (package:front_end/src/fasta/kernel/kernel_function_type_alias_builder.dart:109:12)
  #14     KernelNamedTypeBuilder.build (package:front_end/src/fasta/kernel/kernel_named_type_builder.dart:61:20)
  #15     KernelFunctionBuilder.buildFunction (package:front_end/src/fasta/kernel/kernel_procedure_builder.dart:150:38)
  #16     KernelProcedureBuilder.build (package:front_end/src/fasta/kernel/kernel_procedure_builder.dart:286:28)
  #17     KernelLibraryBuilder.buildBuilder (package:front_end/src/fasta/kernel/kernel_library_builder.dart:752:33)
  #18     SourceLibraryBuilder.build.<anonymous closure> (package:front_end/src/fasta/source/source_library_builder.dart:390:9)
  #19     _HashVMBase&MapMixin&&_LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:356)
  #20     Scope.forEach (package:front_end/src/fasta/scope.dart:243:11)
  #21     LibraryBuilder.forEach (package:front_end/src/fasta/builder/library_builder.dart:190:11)
  #22     SourceLibraryBuilder.build (package:front_end/src/fasta/source/source_library_builder.dart:388:5)
  #23     KernelLibraryBuilder.build (package:front_end/src/fasta/kernel/kernel_library_builder.dart:769:16)
  #24     SourceLoader.buildProgram.<anonymous closure> (package:front_end/src/fasta/source/source_loader.dart:456:31)
  #25     _HashVMBase&MapMixin&&_LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:356)
  #26     SourceLoader.buildProgram (package:front_end/src/fasta/source/source_loader.dart:454:14)
  #27     KernelTarget.buildOutlines (package:front_end/src/fasta/kernel/kernel_target.dart:244:14)
  <asynchronous suspension>
  #28     KernelDriver._compileCycle.<anonymous closure>.<anonymous closure> (package:front_end/src/incremental/kernel_driver.dart:258:28)

[peter-ahe-google]

@askeksa-google is currently looking at fixing crashes in Fasta.