cmd/cgo: cannot convert from type *_Ctype_char to type _Ctype_HANDLE (1.18 regression)

[josharian]

This code compiled on Windows with Go 1.17, but not with Go 1.18:

package p

/*
#include <windows.h>
*/
import "C"

func Error() {
	var x *C.char
	_ = C.HLOCAL(x)
}

The error message is:

p.go:10:15: cannot convert x (variable of type *_Ctype_char) to type _Ctype_HANDLE

Reverting 635e493 allows the code to compile again.

cc @eliasnaur @randall77 @dsnet @bradfitz

[ALTree]

@josharian is this a problem in tip too? (I assume it is). If that's the case, this issue should be put in the 1.19 milestone (to track fixing on tip), and the backport issue that you can ask gopherbot to open will be the one in the 1.18.1 milestone (to track the backporting).

[josharian]

@ALTree oh right. thanks.

@gopherbot please open a backport issue for Go 1.18. This is a compilation regression.

[gopherbot]

Backport issue(s) opened: #51728 (for 1.18).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://go.dev/wiki/MinorReleases.

[bradfitz]

(This bug was minimized from https://github.com/cyolosecurity/certstore/blob/main/certstore_windows.go#L666)

/cc @ianlancetaylor