}

func (check *Checker) assignError(rhs []ast.Expr, l, r int) {
	vars := measure(l, "variable")
	vals := measure(r, "value")
	rhs0 := rhs[0]

	if len(rhs) == 1 {
		if call, _ := ast.Unparen(rhs0).(*ast.CallExpr); call != nil {
			check.errorf(rhs0, WrongAssignCount, "assignment mismatch: %s but %s returns %s", vars, call.Fun, vals)
			return
		}
	}

func (check *Checker) assignError(rhs []syntax.Expr, l, r int) {
	vars := measure(l, "variable")
	vals := measure(r, "value")
	rhs0 := rhs[0]

	if len(rhs) == 1 {
		if call, _ := syntax.Unparen(rhs0).(*syntax.CallExpr); call != nil {
			check.errorf(rhs0, WrongAssignCount, "assignment mismatch: %s but %s returns %s", vars, call.Fun, vals)
			return
		}
	}

package cfg

// This file implements the CFG construction pass.

import (
	"fmt"
	"go/ast"
	"go/token"
)

type builder struct {
	cfg       *CFG
	mayReturn func(*ast.CallExpr) bool
	current   *Block
	lblocks   map[string]*lblock // labeled blocks
	targets   *targets           // linked stack of branch targets
}

func (b *builder) stmt(_s ast.Stmt) {

		}
		ir.Visit(n, c.findExtraCalls)
	}
	c.curfn = nil
	return c
}

func (c *nowritebarrierrecChecker) findExtraCalls(nn ir.Node) {
	if nn.Op() != ir.OCALLFUNC {
		return
	}
	n := nn.(*ir.CallExpr)
	if n.Fun == nil || n.Fun.Op() != ir.ONAME {
		return
	}
	fn := n.Fun.(*ir.Name)
	if fn.Class != ir.PFUNC || fn.Defn == nil {
		return
	}
	if types.RuntimeSymName(fn.Sym()) != "systemstack" {
		return
	}

		if n.Max != nil {
			// - 3-index slices always require the 2nd and 3rd index
			break
		}
		if s, _ := n.X.(*ast.Ident); s != nil {
			// the array/slice object is a single identifier
			if call, _ := n.High.(*ast.CallExpr); call != nil && len(call.Args) == 1 && !call.Ellipsis.IsValid() {
				// the high expression is a function call with a single argument
				if fun, _ := call.Fun.(*ast.Ident); fun != nil && fun.Name == "len" {

		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)
				}

		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)
				}

	//     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  .  .  .  .  .  .  .  }

		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.