From ddb5a42b25c63df9f11669bd4b14eeebcd2ba2bb Mon Sep 17 00:00:00 2001 From: Robert Griesemer Date: Wed, 22 Sep 2021 21:57:19 -0700 Subject: cmd/compile/internal/types2: avoid "declared but not used" errors for invalid code Agressively mark all LHS variables in assignments as used if there is any error in the (entire) assignment. This reduces the number of spurious "declared but not used" errors in programs that are invalid in the first place. This behavior is closer to the behavior of the compiler's original type checker (types1) and lets us remove lines of the form "_ = variable" just to satisfy test cases. It also makes more important errors visible by not crowding them out. Remove the Checker.useLHS function and use Checker.use instead: useLHS didn't evaluate top-level variables, but we actually want them to be evaluated in an error scenario so that they are getting used (and thus we don't get the "declared but not used" error). Fixes #42937. Change-Id: Idda460f6b81c66735bf9fd597c54188949bf12b8 Reviewed-on: https://go-review.googlesource.com/c/go/+/351730 Trust: Robert Griesemer Run-TryBot: Robert Griesemer TryBot-Result: Go Bot Reviewed-by: Robert Findley --- test/interface/pointer.go | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'test/interface') diff --git a/test/interface/pointer.go b/test/interface/pointer.go index c21e4da390..a71b3f4bf8 100644 --- a/test/interface/pointer.go +++ b/test/interface/pointer.go @@ -24,7 +24,6 @@ type Start struct { func (start *Start) Next() *Inst { return nil } - func AddInst(Inst) *Inst { print("ok in addinst\n") return nil @@ -33,8 +32,6 @@ func AddInst(Inst) *Inst { func main() { print("call addinst\n") var x Inst = AddInst(new(Start)) // ERROR "pointer to interface|incompatible type" - _ = x print("return from addinst\n") - var y *Inst = new(Start) // ERROR "pointer to interface|incompatible type" - _ = y + var y *Inst = new(Start) // ERROR "pointer to interface|incompatible type" } -- cgit v1.3