Initial commit: Go 1.23 release state

test/typeswitch2b.go

@@ -0,0 +1,20 @@
+// errorcheck
+
+// Copyright 2019 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.
+
+// Verify that various erroneous type switches are caught by the compiler.
+// Does not compile.
+
+package main
+
+func notused(x interface{}) {
+	// The first t is in a different scope than the 2nd t; it cannot
+	// be accessed (=> declared and not used error); but it is legal
+	// to declare it.
+	switch t := 0; t := x.(type) { // ERROR "declared and not used"
+	case int:
+		_ = t // this is using the t of "t := x.(type)"
+	}
+}