go source for verification 2026-05-22

test/assign.go

@@ -0,0 +1,71 @@
+// errorcheck
+
+// Copyright 2009 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 simple assignment errors are caught by the compiler.
+// Does not compile.
+
+package main
+
+import (
+	"sync"
+	"time"
+)
+
+type T struct {
+	int
+	sync.Mutex
+}
+
+func main() {
+	{
+		var x, y sync.Mutex
+		x = y // ok
+		_ = x
+	}
+	{
+		var x, y T
+		x = y // ok
+		_ = x
+	}
+	{
+		var x, y [2]sync.Mutex
+		x = y // ok
+		_ = x
+	}
+	{
+		var x, y [2]T
+		x = y // ok
+		_ = x
+	}
+	{
+		x := time.Time{0, 0, nil} // ERROR "assignment.*Time"
+		_ = x
+	}
+	{
+		x := sync.Mutex{key: 0} // ERROR "(unknown|assignment).*Mutex"
+		_ = x
+	}
+	{
+		x := &sync.Mutex{} // ok
+		var y sync.Mutex   // ok
+		y = *x             // ok
+		*x = y             // ok
+		_ = x
+		_ = y
+	}
+	{
+		var x = 1
+		{
+			x, x := 2, 3 // ERROR ".*x.* repeated on left side of :=|x redeclared in this block"
+			_ = x
+		}
+		_ = x
+	}
+	{
+		a, a := 1, 2 // ERROR ".*a.* repeated on left side of :=|a redeclared in this block"
+		_ = a
+	}
+}