Server error: "Missing implementation of visitFunctionExpression"

[DanTup]

Raised at Dart-Code/Dart-Code#4666, I was able to reduce it to this (it seems to require const on the constructor and the function call in the assert):

class StylishBottomBar  {
  const StylishBottomBar({
    List<String?> items,
  }) : assert(items.every((String? item) => item != null));
}

It causes the server to terminate with the following in the log:

[12:12:14 PM] [Analyzer] [Error] Unhandled exception:
Exception: Missing implementation of visitFunctionExpression
#0      ThrowingAstVisitor._throw (package:analyzer/dart/ast/visitor.dart:2842:5)
#1      ThrowingAstVisitor.visitFunctionExpression (package:analyzer/dart/ast/visitor.dart:2514:58)
#2      FunctionExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:6124:50)
#3      AstBinaryWriter._writeNodeList (package:analyzer/src/summary2/ast_binary_writer.dart:939:19)
#4      AstBinaryWriter.visitArgumentList …

I'm not sure why the calls tack is truncated, but below is a screenshot of it in the debugger (I couldn't dump it as text, sorry).

(@scheglov FYI)

[srawlins]

CC @kallentu , looks like a bug specific to const constructor asserts; you probably have the freshest notion of this code :)

[kallentu]

I looked into what makes the difference between const and non-consting that constructor and it's the call of this line:

sdk/pkg/analyzer/lib/src/summary2/bundle_writer.dart

Line 208 in d9363a6

_resolutionSink._writeNodeList(element.constantInitializers);

And all this happens without ever entering the constant evaluator, so I suspect @scheglov might have more context on this?

The _constantInitializers do have a FunctionExpression in there ((String? item) => item != null) and the AstBinaryWriter doesn't implement it, but I'm not sure if it's as straight forward as making a visitFunctionExpression or if something else is wrong up the pipeline.

[shashkiranr]

Hi,

Any Workaround for this issue? The dart analyser keeps failing and the auto complete feature in Android Studio for Flutter seems to fail with it in classes where const constructor and assert are used and referenced

[srawlins]

@scheglov can you look at this?

[kallentu]

@srawlins I can take a go at fixing this. I was taking a look at it yesterday.

[scheglov]

We might need to use replaceNotSerializableNode in one more place.