cmd/compile: poor error message when invoking method on embedded type

[dsymonds]

Please answer these questions before submitting your issue. Thanks!

1. What version of Go are you using (go version)?

go1.6.2

1. What operating system and processor architecture are you using (go env)?

The playground

1. What did you do?

https://play.golang.org/p/hsjwmQwtsb

Relevant snippet:

func TestFoo(t *testing.T) {
    t.Fail("what?")
}

1. What did you expect to see?

prog.go:14: too many arguments in call to t.Fail

1. What did you see instead?

prog.go:14: too many arguments in call to t.common.Fail

The .common bit is unexpected and an implementation detail. Running godoc testing Fail shows a simple method func (c *T) Fail(), and the fact that testing.T embeds testing.common does not seem useful.

[odeke-em]

This bug can now be closed. With Go1.8 +e776975, we'll now have a nice message talking about t.common.Fail failing instead of just t.Fail, and that was even fixed in Go1.7

$ go run main.go 
# command-line-arguments
./main.go:14: too many arguments in call to t.common.Fail
	have (string)
	want ()

The too many arguments improved message was implemented in https://go-review.googlesource.com/25156.

I'll let @bradfitz close it so that we can properly triage and note it as a Go1.7/8 fixed bug.

[ianlancetaylor]

I don't think tracking setting the milestone of a closed bug to a closed milestone makes much difference. Closing this issue.

[dsymonds]

Sorry, this isn't fixed. My complaint wasn't about the "too many arguments" part. It was about the error referring to the unexported embedded type.

$ go version
go version devel +d698e614a2 Tue Jan 3 19:23:23 2017 +0000 linux/amd64
$ go test
...
./x_test.go:6: too many arguments in call to t.common.Fail
        have (string)
        want ()

That t.common.Fail is the problematic part. My code doesn't (and can't) refer to t.common.

[odeke-em]

Am sorry about that @dsymonds and @ianlancetaylor, I totally misunderstood that issue, that 1AM clarity. Yap your issue still stands.

[linsite]

2025.3.5 updates

hi, @dsymonds, newly test with Go 1.24 shows as below.

./prog.go:14:9: too many arguments in call to t.Fail
	have (string)
	want ()

Go build failed.