cmd/vet: added some missing copylock checks

Fixes #14664

Change-Id: I8bda2435857772f590859808904c48d768b87d46
Reviewed-on: https://go-review.googlesource.com/20254
Run-TryBot: Rob Pike <[email protected]>
Reviewed-by: Rob Pike <[email protected]>

Author: valyala

src/cmd/vet/copylock.go

@@ -18,7 +18,7 @@ func init() {
 	register("copylocks",
 		"check that locks are not passed by value",
 		checkCopyLocks,
-		funcDecl, rangeStmt, funcLit, assignStmt)
+		funcDecl, rangeStmt, funcLit, assignStmt, genDecl, compositeLit)
 }
 
 // checkCopyLocks checks whether node might
@@ -33,15 +33,47 @@ func checkCopyLocks(f *File, node ast.Node) {
 		checkCopyLocksFunc(f, "func", nil, node.Type)
 	case *ast.AssignStmt:
 		checkCopyLocksAssign(f, node)
+	case *ast.GenDecl:
+		checkCopyLocksGenDecl(f, node)
+	case *ast.CompositeLit:
+		checkCopyCompositeLit(f, node)
 	}
 }
 
 // checkCopyLocksAssign checks whether an assignment
 // copies a lock.
 func checkCopyLocksAssign(f *File, as *ast.AssignStmt) {
-	for _, x := range as.Lhs {
-		if path := lockPath(f.pkg.typesPkg, f.pkg.types[x].Type); path != nil {
-			f.Badf(x.Pos(), "assignment copies lock value to %v: %v", f.gofmt(x), path)
+	for i, x := range as.Rhs {
+		if path := lockPathRhs(f, x); path != nil {
+			f.Badf(x.Pos(), "assignment copies lock value to %v: %v", f.gofmt(as.Lhs[i]), path)
+		}
+	}
+}
+
+// checkCopyLocksGenDecl checks whether lock is copied
+// in variable declaration.
+func checkCopyLocksGenDecl(f *File, gd *ast.GenDecl) {
+	if gd.Tok != token.VAR {
+		return
+	}
+	for _, spec := range gd.Specs {
+		valueSpec := spec.(*ast.ValueSpec)
+		for i, x := range valueSpec.Values {
+			if path := lockPathRhs(f, x); path != nil {
+				f.Badf(x.Pos(), "variable declaration copies lock value to %v: %v", valueSpec.Names[i].Name, path)
+			}
+		}
+	}
+}
+
+// checkCopyCompositeLit detects lock copy inside a composite literal
+func checkCopyCompositeLit(f *File, cl *ast.CompositeLit) {
+	for _, x := range cl.Elts {
+		if node, ok := x.(*ast.KeyValueExpr); ok {
+			x = node.Value
+		}
+		if path := lockPathRhs(f, x); path != nil {
+			f.Badf(x.Pos(), "literal copies lock value from %v: %v", f.gofmt(x), path)
 		}
 	}
 }
@@ -132,6 +164,13 @@ func (path typePath) String() string {
 	return buf.String()
 }
 
+func lockPathRhs(f *File, x ast.Expr) typePath {
+	if _, ok := x.(*ast.CompositeLit); ok {
+		return nil
+	}
+	return lockPath(f.pkg.typesPkg, f.pkg.types[x].Type)
+}
+
 // lockPath returns a typePath describing the location of a lock value
 // contained in typ. If there is no contained lock, it returns nil.
 func lockPath(tpkg *types.Package, typ types.Type) typePath {

src/cmd/vet/testdata/copylock.go

@@ -7,6 +7,21 @@ func OkFunc() {
 	p := x
 	var y sync.Mutex
 	p = &y
+
+	var z = sync.Mutex{}
+	w := sync.Mutex{}
+
+	w = sync.Mutex{}
+	q := struct{ L sync.Mutex }{
+		L: sync.Mutex{},
+	}
+
+	yy := []Tlock{
+		sync.Tlock{},
+		sync.Tlock{
+			once: sync.Once{},
+		},
+	}
 }
 
 type Tlock struct {
@@ -25,4 +40,19 @@ func BadFunc() {
 	tp = &t
 	*tp = t // ERROR "assignment copies lock value to \*tp: testdata.Tlock contains sync.Once contains sync.Mutex"
 	t = *tp // ERROR "assignment copies lock value to t: testdata.Tlock contains sync.Once contains sync.Mutex"
+
+	y := *x   // ERROR "assignment copies lock value to y: sync.Mutex"
+	var z = t // ERROR "variable declaration copies lock value to z: testdata.Tlock contains sync.Once contains sync.Mutex"
+
+	w := struct{ L sync.Mutex }{
+		L: *x, // ERROR "literal copies lock value from \*x: sync.Mutex"
+	}
+	var q = map[int]Tlock{
+		1: t,   // ERROR "literal copies lock value from t: testdata.Tlock contains sync.Once contains sync.Mutex"
+		2: *tp, // ERROR "literal copies lock value from \*tp: testdata.Tlock contains sync.Once contains sync.Mutex"
+	}
+	yy := []Tlock{
+		t,   // ERROR "literal copies lock value from t: testdata.Tlock contains sync.Once contains sync.Mutex"
+		*tp, // ERROR "literal copies lock value from \*tp: testdata.Tlock contains sync.Once contains sync.Mutex"
+	}
 }