nodeFilter := []ast.Node{
		(*ast.CallExpr)(nil),
	}
	inspect.Preorder(nodeFilter, func(n ast.Node) {
		call := n.(*ast.CallExpr)
		if !isSignalNotify(pass.TypesInfo, call) {
			return
		}
		var chanDecl *ast.CallExpr
		switch arg := call.Args[0].(type) {
		case *ast.Ident:
			if decl, ok := findDecl(arg).(*ast.CallExpr); ok {
				chanDecl = decl
			}
		case *ast.CallExpr:

// hasDots reports whether the last argument in the call is followed by ...
func hasDots(call *syntax.CallExpr) bool { return call.HasDots }

// dddErrPos returns the node (poser) for reporting an invalid ... use in a call.
func dddErrPos(call *syntax.CallExpr) *syntax.CallExpr {
	// TODO(gri) should use "..." instead of call position
	return call
}

}

func run(pass *analysis.Pass) (interface{}, error) {
	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)

	nodeFilter := []ast.Node{
		(*ast.CallExpr)(nil),
	}
	inspect.Preorder(nodeFilter, func(n ast.Node) {
		call := n.(*ast.CallExpr)
		b, ok := typeutil.Callee(pass.TypesInfo, call).(*types.Builtin)
		if ok && b.Name() == "append" && len(call.Args) == 1 {
			pass.ReportRangef(call, "append with no values")
		}

func hasDots(call *ast.CallExpr) bool { return call.Ellipsis.IsValid() }

// dddErrPos returns the positioner for reporting an invalid ... use in a call.
func dddErrPos(call *ast.CallExpr) positioner { return atPos(call.Ellipsis) }

// argErrPos returns positioner for reporting an invalid argument count.
func argErrPos(call *ast.CallExpr) positioner { return inNode(call, call.Rparen) }

)

// Callee returns the named target of a function call, if any:
// a function, method, builtin, or variable.
//
// Functions and methods may potentially have type parameters.
func Callee(info *types.Info, call *ast.CallExpr) types.Object {
	fun := astutil.Unparen(call.Fun)

	// Look through type instantiation if necessary.
	isInstance := false
	switch fun.(type) {
	case *ast.IndexExpr, *ast.IndexListExpr:

	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)

	nodeFilter := []ast.Node{
		(*ast.CallExpr)(nil),
		(*ast.StarExpr)(nil),
		(*ast.UnaryExpr)(nil),
	}
	inspect.Preorder(nodeFilter, func(n ast.Node) {
		switch x := n.(type) {
		case *ast.CallExpr:
			if len(x.Args) == 1 &&
				hasBasicType(pass.TypesInfo, x.Fun, types.UnsafePointer) &&

		(*ast.FuncDecl)(nil),
		(*ast.GoStmt)(nil),
		(*ast.CallExpr)(nil),
	}, func(node ast.Node, push bool) bool {
		if !push {
			return false
		}
		switch node := node.(type) {
		case *ast.FuncDecl:
			return hasBenchmarkOrTestParams(node)

		case *ast.GoStmt:
			c := goAsyncCall(pass.TypesInfo, node, toDecl)
			addCall(c)

		case *ast.CallExpr:
			c := tRunAsyncCall(pass.TypesInfo, node)
			addCall(c)
		}

	// skip the traversal.
	if !analysisutil.Imports(pass.Pkg, "net/http") {
		return nil, nil
	}

	nodeFilter := []ast.Node{
		(*ast.CallExpr)(nil),
	}
	inspect.WithStack(nodeFilter, func(n ast.Node, push bool, stack []ast.Node) bool {
		if !push {
			return true
		}
		call := n.(*ast.CallExpr)
		if !isHTTPFuncOrMethodOnClient(pass.TypesInfo, call) {
			return true // the function call is not related to this check.
		}

	// TODO(taking): Consider using a prepass to collect typeutil.Callees.

	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)

	nodeFilter := []ast.Node{
		(*ast.CallExpr)(nil),
	}
	inspect.Preorder(nodeFilter, func(n ast.Node) {
		call := n.(*ast.CallExpr)
		fn := typeutil.StaticCallee(pass.TypesInfo, call)
		if fn == nil {
			return // not a static call
		}

		// Classify the callee (without allocating memory).

	// TODO(taking): Consider using a prepass to collect typeutil.Callees.

	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)

	nodeFilter := []ast.Node{
		(*ast.CallExpr)(nil),
	}
	inspect.Preorder(nodeFilter, func(n ast.Node) {
		call := n.(*ast.CallExpr)
		fn, ok := typeutil.Callee(pass.TypesInfo, call).(*types.Func)
		if !ok {
			return
		}
		if !isTimeDotFormat(fn) && !isTimeDotParse(fn) {
			return
		}