/cc @griesemer

I also didn't check what go/types does here. It's probably worth seeing if both typecheckers do the right thing when one uses undefined names inside common combinations of types (map+slice, func+map, slice+pointer, etc).

Simpler repro:

	var p *func(Undefined)
	var v int = p

Yields two errors.

Contrast with:

	var p *struct { x Undefined }
	var v int = p

which yields one.

Arguably, two errors here is correct: the name "Undefined" is not defined, which makes it bad. But the assignment of a pointer-to-function type to an integer is also an error, since that's wrong no matter what Undefined resolves to.

However, whether we emit one or two errors, we should probably be consistent between *func(Undefined) and *struct { x Undefined }, and I can't immediately identify why we're not. Looking at the code, it seems like both should mark the composite type as "broke".

Simpler repro:

	var p *func(Undefined)
	var v int = p

Yields two errors.

Contrast with:

	var p *struct { x Undefined }
	var v int = p

which yields one.

What commit you use? On current tip 7d30af8:

var p *struct { x Undefined }
var v int = p

yields two errors.

Simpler repro:

	var p *func(Undefined)
	var v int = p

Yields two errors.
Contrast with:

	var p *struct { x Undefined }
	var v int = p

which yields one.

What commit you use? On current tip 7d30af8:

var p *struct { x Undefined }
var v int = p

yields two errors.

Oh, go1.13.5 yields one error only.

Simpler repro:

	var p *func(Undefined)
	var v int = p

Yields two errors.
Contrast with:

	var p *struct { x Undefined }
	var v int = p

which yields one.

What commit you use? On current tip 7d30af8:

var p *struct { x Undefined }
var v int = p

yields two errors.

go tip yields two errors due to #33947.

I also didn't check what go/types does here. It's probably worth seeing if both typecheckers do the right thing when one uses undefined names inside common combinations of types (map+slice, func+map, slice+pointer, etc).

go/types yields one error only:

$ go run types.go
2019/12/15 01:50:58 src.go:6:14: undeclared name: Undefined
exit status 1