cmd/compile: suboptimal error for &T{} literal mismatch

[dsymonds]

Does this issue reproduce with the latest release?

In the playground, yes.

What did you do?

https://play.golang.org/p/uQjX9qTwBz1

package main

type S struct {
	Name T
}

type T struct {
	First string
}

func main() {
	_ = &S{
		Name: &T{First: "Rob"},
	}
}

What did you expect to see?

An error message pointing out the T vs. *T type problem.

What did you see instead?

prog.go:13:7: cannot use T literal (type *T) as type T in field value

The error message is there, but it is phrased oddly. cannot use T literal is confusing. I'm using a &T literal. If you put aside the parenthetical for a moment, the oddness is apparent: cannot use T literal as type T in field value. I think this error message could be improved.

[smasher164]

It is also odd because without the parentheses, the phrase T literal as type T compares a value with a type.
Would the following be a more clear message?

prog.go:13:7: cannot use literal of type *T for field value of type T.

[bcmills]

CC: @randall77 @griesemer

[rsc]

It should say &T literal.

[griesemer]

typecheckcomplit makes a copy (typecheck.go:2915) of the complit node it type-checks and then modifies its Op in place. Because n.Orig points to n, this implicitly modifies also n.Orig. During printing, the original node doesn't have the correct Op anymore leading to this error.

[gopherbot]

Change https://golang.org/cl/136395 mentions this issue: cmd/compile: fix error message for &T{} literal mismatch

[gopherbot]

Change https://golang.org/cl/136396 mentions this issue: cmd/compile/internal/gc: minor code reorg (cleanup)