Analyzer fails on implicit tearoff through explicit instantiation of extension method

[johnniwinther]

With https://dart-review.googlesource.com/c/sdk/+/215021 the test language/explicit_type_instantiation_parsing_test has been updated to use perform an explicit instantiation on a receiver that is callable through an extension method:

...
Object? v = null;
...
extension <T extends Object?> on T {
  ...
  Object? call<R, S>([_]) => null;
  ...
}
void main() {
  ...
  // Since `v` has type `Object?`, this is an extension invocation of the
  // implicit `call` tear off.
  /**/ v<int, String>; // line 312
}

This case is not handled by the analyzer which fails with

static error failures:
- Unexpected error at line 312, column 8, length 1: COMPILE_TIME_ERROR.DISALLOWED_TYPE_INSTANTIATION_EXPRESSION

[scheglov]

@srawlins

[srawlins]

Thanks for the bug!