Initial commit: Go 1.23 release state

test/switch6.go

@@ -0,0 +1,46 @@
+// errorcheck
+
+// Copyright 2016 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.
+
+// Check the compiler's switch handling that happens
+// at typechecking time.
+// This must be separate from other checks,
+// because errors during typechecking
+// prevent other errors from being discovered.
+
+package main
+
+// Verify that type switch statements with impossible cases are detected by the compiler.
+func f0(e error) {
+	switch e.(type) {
+	case int: // ERROR "impossible type switch case: (int\n\t)?e \(.*type error\) cannot have dynamic type int \(missing method Error\)"
+	}
+}
+
+// Verify that the compiler rejects multiple default cases.
+func f1(e interface{}) {
+	switch e {
+	default:
+	default: // ERROR "multiple defaults( in switch)?"
+	}
+	switch e.(type) {
+	default:
+	default: // ERROR "multiple defaults( in switch)?"
+	}
+}
+
+type I interface {
+	Foo()
+}
+
+type X int
+
+func (*X) Foo() {}
+func f2() {
+	var i I
+	switch i.(type) {
+	case X: // ERROR "impossible type switch case: (X\n\t)?i \(.*type I\) cannot have dynamic type X \(method Foo has pointer receiver\)"
+	}
+}