types := make(map[syntax.Expr]TypeAndValue)
		mustTypecheck(src, nil, &Info{Types: types})

		var n int
		for x, tv := range types {
			if x, _ := x.(*syntax.CallExpr); x != nil {
				// there must be exactly one CallExpr which is the P(val) conversion
				n++
				tpar, _ := tv.Type.(*TypeParam)
				if tpar == nil {
					t.Fatalf("%s: got type %s, want type parameter", ExprString(x), tv.Type)
				}

	//     24  .  .  .  Body: *ast.BlockStmt {
	//     25  .  .  .  .  Lbrace: 3:13
	//     26  .  .  .  .  List: []ast.Stmt (len = 1) {
	//     27  .  .  .  .  .  0: *ast.ExprStmt {
	//     28  .  .  .  .  .  .  X: *ast.CallExpr {
	//     29  .  .  .  .  .  .  .  Fun: *ast.Ident {
	//     30  .  .  .  .  .  .  .  .  NamePos: 4:2
	//     31  .  .  .  .  .  .  .  .  Name: "println"
	//     32  .  .  .  .  .  .  .  }

		types := make(map[ast.Expr]TypeAndValue)
		mustTypecheck(src, nil, &Info{Types: types})

		var n int
		for x, tv := range types {
			if x, _ := x.(*ast.CallExpr); x != nil {
				// there must be exactly one CallExpr which is the P(val) conversion
				n++
				tpar, _ := tv.Type.(*TypeParam)
				if tpar == nil {
					t.Fatalf("%s: got type %s, want type parameter", ExprString(x), tv.Type)
				}

		children = append(children,
			tok(n.Lbrace, len("{")),
			tok(n.Rbrace, len("}")))

	case *ast.BranchStmt:
		children = append(children,
			tok(n.TokPos, len(n.Tok.String())))

	case *ast.CallExpr:
		children = append(children,
			tok(n.Lparen, len("(")),
			tok(n.Rparen, len(")")))
		if n.Ellipsis != 0 {
			children = append(children, tok(n.Ellipsis, len("...")))
		}

	case *ast.CaseClause:

//	func(a int) {
//		println(byval)
//		byref++
//	}(42)
//
// becomes:
//
//	func(byval int, &byref *int, a int) {
//		println(byval)
//		(*&byref)++
//	}(byval, &byref, 42)
func directClosureCall(n *ir.CallExpr) {
	clo := n.Fun.(*ir.ClosureExpr)
	clofn := clo.Func

	if ir.IsTrivialClosure(clo) {
		return // leave for walkClosure to handle
	}

	// We are going to insert captured variables before input args.

		if n.High != nil {
			Walk(v, n.High)
		}
		if n.Max != nil {
			Walk(v, n.Max)
		}

	case *TypeAssertExpr:
		Walk(v, n.X)
		if n.Type != nil {
			Walk(v, n.Type)
		}

	case *CallExpr:
		Walk(v, n.Fun)
		walkList(v, n.Args)

	case *StarExpr:
		Walk(v, n.X)

	case *UnaryExpr:
		Walk(v, n.X)

	case *BinaryExpr:
		Walk(v, n.X)
		Walk(v, n.Y)

	{name: "recv", format: "package main; var x = «<-»x"},
	{name: "call", format: "package main; var x = «f(«1»)»", parseMultiplier: 2},    // Parser nodes: Ident, CallExpr
	{name: "conv", format: "package main; var x = «(*T)(«1»)»", parseMultiplier: 2}, // Parser nodes: ParenExpr, CallExpr
	{name: "label", format: "package main; func main() { «Label:» }"},

		X   Expr  // X.(type)
		expr
	}

	Operation struct {
		Op   Operator
		X, Y Expr // Y == nil means unary expression
		expr
	}

	// Fun(ArgList[0], ArgList[1], ...)
	CallExpr struct {
		Fun     Expr
		ArgList []Expr // nil means no arguments
		HasDots bool   // last argument is followed by ...
		expr
	}

	// ElemList[0], ElemList[1], ...
	ListExpr struct {

		} else {
			check.mono.recordInstance(check.pkg, pos, tparams, targs, xlist)
		}
	}).describef(pos, "verify instantiation")

	return inst
}

func (check *Checker) callExpr(x *operand, call *syntax.CallExpr) exprKind {
	var inst *syntax.IndexExpr // function instantiation, if any
	if iexpr, _ := call.Fun.(*syntax.IndexExpr); iexpr != nil {
		if check.indexExpr(x, iexpr) {

		} else {
			check.mono.recordInstance(check.pkg, pos, tparams, targs, xlist)
		}
	}).describef(atPos(pos), "verify instantiation")

	return inst
}

func (check *Checker) callExpr(x *operand, call *ast.CallExpr) exprKind {
	ix := typeparams.UnpackIndexExpr(call.Fun)
	if ix != nil {
		if check.indexExpr(x, ix) {
			// Delay function instantiation to argument checking,