Support arbitrary type argument count in functions in dart2js

[nickclmb]

Hi all,

Dart2js crashes with error because of this unimplemented TODO:
https://github.com/dart-lang/sdk/blob/master/pkg/compiler/lib/src/ssa/builder_kernel.dart#L4387

Seems like critical for us, can you please check?

The compiler crashed: Internal Error: Generic function instantiation not implemented for 8 type arguments
#0      CompilerDiagnosticReporter.internalError (file:///tmp/tmpAi0tzS/dart-2.0.0-dev.67.0/dart/pkg/compiler/lib/src/compiler.dart:868:5)
#1      KernelSsaGraphBuilder.visitInstantiation (file:///tmp/tmpAi0tzS/dart-2.0.0-dev.67.0/dart/pkg/compiler/lib/src/ssa/builder_kernel.dart:4375:16)
#2      Instantiation.accept (package:kernel/ast.dart:2959:36)

[nickclmb]

Same here:
https://github.com/dart-lang/sdk/blob/master/pkg/compiler/lib/src/js_backend/constant_emitter.dart#L341

[nickclmb]

@kevmoo @johnniwinther

[sigmundch]

Because the full solution will take us longer to implement, we are landing first a change to raise the limit manually. We should be able to support up to 20 type arguments after the change lands. Our hope is that this will unblock you until we have the full solution ready.

CL from @johnniwinther is here https://dart-review.googlesource.com/c/sdk/+/65541

[nickclmb]

Thanks for update and your work. 20 should be enough, so far we have 9 generics max. Looking forward for hotfix. Thanks in advance