Kunpei Sakai <******@****.***> 1505438687 +0900

// compile

// Copyright 2014 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.

// PR61273: gccgo failed to compile a SendStmt in the PostStmt of a ForClause
// that involved predefined constants.

package main

func main() {
	c := make(chan bool, 1)
	for ; false; c <- false {
	}

// is "".
func (check *Checker) isTerminating(s syntax.Stmt, label string) bool {
	switch s := s.(type) {
	default:
		panic("unreachable")

	case *syntax.DeclStmt, *syntax.EmptyStmt, *syntax.SendStmt,
		*syntax.AssignStmt, *syntax.CallStmt:
		// no chance

	case *syntax.LabeledStmt:
		return check.isTerminating(s.Stmt, s.Label.Value)

	case *syntax.ExprStmt:

	var dflt *ir.CommClause
	for _, cas := range cases {
		ir.SetPos(cas)
		n := cas.Comm
		if n == nil {
			dflt = cas
			continue
		}
		switch n.Op() {
		case ir.OSEND:
			n := n.(*ir.SendStmt)
			n.Value = typecheck.NodAddr(n.Value)
			n.Value = typecheck.Expr(n.Value)

		case ir.OSELRECV2:
			n := n.(*ir.AssignListStmt)
			if !ir.IsBlank(n.Lhs[0]) {
				n.Lhs[0] = typecheck.NodAddr(n.Lhs[0])

// is "".
func (check *Checker) isTerminating(s ast.Stmt, label string) bool {
	switch s := s.(type) {
	default:
		panic("unreachable")

	case *ast.BadStmt, *ast.DeclStmt, *ast.EmptyStmt, *ast.SendStmt,
		*ast.IncDecStmt, *ast.AssignStmt, *ast.GoStmt, *ast.DeferStmt,
		*ast.RangeStmt:
		// no chance

	case *ast.LabeledStmt:
		return check.isTerminating(s.Stmt, s.Label.Name)

	case *ast.ExprStmt:

		// case *InterfaceType:
		// case *FuncType:
		// case *MapType:
		// case *ChanType:

		// statements
		// case *EmptyStmt:
		// case *LabeledStmt:
		// case *BlockStmt:
		// case *ExprStmt:
		case *SendStmt:
			m = n.Chan
		// case *DeclStmt:
		case *AssignStmt:
			m = n.Lhs
		// case *BranchStmt:
		// case *CallStmt:
		// case *ReturnStmt:
		// case *IfStmt:
		// case *ForStmt:
		// case *SwitchStmt:

	case *ast.AssignStmt,
		*ast.BadStmt,
		*ast.DeclStmt,
		*ast.DeferStmt,
		*ast.EmptyStmt,
		*ast.ExprStmt,
		*ast.GoStmt,
		*ast.IncDecStmt,
		*ast.ReturnStmt,
		*ast.SendStmt:
		// no statements inside

	case *ast.BlockStmt:
		for _, stmt := range x.List {
			d.findLabels(stmt)
		}

	case *ast.BranchStmt:
		switch x.Tok {
		case token.GOTO:
			if x.Label != nil {

		Stmt  Stmt
	}

	// An ExprStmt node represents a (stand-alone) expression
	// in a statement list.
	//
	ExprStmt struct {
		X Expr // expression
	}

	// A SendStmt node represents a send statement.
	SendStmt struct {
		Chan  Expr
		Arrow token.Pos // position of "<-"
		Value Expr
	}

	// An IncDecStmt node represents an increment or decrement statement.
	IncDecStmt struct {

		return 1 << nRangeStmt
	case *ast.ReturnStmt:
		return 1 << nReturnStmt
	case *ast.SelectStmt:
		return 1 << nSelectStmt
	case *ast.SelectorExpr:
		return 1 << nSelectorExpr
	case *ast.SendStmt:
		return 1 << nSendStmt
	case *ast.SliceExpr:
		return 1 << nSliceExpr
	case *ast.StarExpr:
		return 1 << nStarExpr
	case *ast.StructType:
		return 1 << nStructType
	case *ast.SwitchStmt:

			tok(n.Return, len("return")))

	case *ast.SelectStmt:
		children = append(children,
			tok(n.Select, len("select")))

	case *ast.SelectorExpr:
		// nop

	case *ast.SendStmt:
		children = append(children,
			tok(n.Arrow, len("<-")))

	case *ast.SliceExpr:
		children = append(children,
			tok(n.Lbrack, len("[")),
			tok(n.Rbrack, len("]")))

	case *ast.StarExpr: