From: Robert Griesemer <gri@golang.org>
Date: Wed, 21 Jun 2023 18:14:34 +0000 (-0700)
Subject: go/types, types2: avoid spurious "declared and not used" error
X-Git-Tag: go1.21rc3~2^2~78
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=b1f1fb2950814ae2b69e64537ecd96f13ae32627;p=gostls13.git

go/types, types2: avoid spurious "declared and not used" error

Fixes #60906.

Change-Id: Iba117b36041f72a54ce82cc914f8fa3b07a6fb2e
Reviewed-on: https://go-review.googlesource.com/c/go/+/504877
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
---

diff --git a/src/cmd/compile/internal/types2/index.go b/src/cmd/compile/internal/types2/index.go
index 4fbe064da6..3ebe851355 100644
--- a/src/cmd/compile/internal/types2/index.go
+++ b/src/cmd/compile/internal/types2/index.go
@@ -184,6 +184,7 @@ func (check *Checker) indexExpr(x *operand, e *syntax.IndexExpr) (isFuncInst boo
 
 	if !valid {
 		check.errorf(e.Pos(), NonSliceableOperand, invalidOp+"cannot index %s", x)
+		check.use(e.Index)
 		x.mode = invalid
 		return false
 	}
diff --git a/src/go/types/index.go b/src/go/types/index.go
index 1bcfb38feb..c1c0f40e87 100644
--- a/src/go/types/index.go
+++ b/src/go/types/index.go
@@ -186,6 +186,7 @@ func (check *Checker) indexExpr(x *operand, e *typeparams.IndexExpr) (isFuncInst
 	if !valid {
 		// types2 uses the position of '[' for the error
 		check.errorf(x, NonIndexableOperand, invalidOp+"cannot index %s", x)
+		check.use(e.Indices...)
 		x.mode = invalid
 		return false
 	}
diff --git a/src/internal/types/testdata/fixedbugs/issue60906.go b/src/internal/types/testdata/fixedbugs/issue60906.go
new file mode 100644
index 0000000000..2744e89455
--- /dev/null
+++ b/src/internal/types/testdata/fixedbugs/issue60906.go
@@ -0,0 +1,11 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+func _() {
+	var x int
+	var f func() []int
+	_ = f /* ERROR "cannot index f" */ [x]
+}