return andArg(x.X) + " && " + andArg(x.Y)
}

func andArg(x Expr) string {
	s := x.String()
	if _, ok := x.(*OrExpr); ok {
		s = "(" + s + ")"
	}
	return s
}

func and(x, y Expr) Expr {
	return &AndExpr{x, y}
}

// An OrExpr represents the expression X || Y.
type OrExpr struct {
	X, Y Expr
}

func (x *OrExpr) isExpr() {}

	}
	return n
}

// tcSlice typechecks an OSLICE or OSLICE3 node.
func tcSlice(n *ir.SliceExpr) ir.Node {
	n.X = DefaultLit(Expr(n.X), nil)
	n.Low = indexlit(Expr(n.Low))
	n.High = indexlit(Expr(n.High))
	n.Max = indexlit(Expr(n.Max))
	hasmax := n.Op().IsSlice3()
	l := n.X
	if l.Type() == nil {
		n.SetType(nil)
		return n
	}
	if l.Type().IsArray() {

			return n
		}
		a := ir.Copy(n).(*ir.UnaryExpr)
		a.X = l
		return walkExpr(typecheck.Expr(a), init)

	case ir.ODOT, ir.ODOTPTR:
		n := n.(*ir.SelectorExpr)
		l := safeExpr(n.X, init)
		if l == n.X {
			return n
		}
		a := ir.Copy(n).(*ir.SelectorExpr)
		a.X = l
		return walkExpr(typecheck.Expr(a), init)

	case ir.ODEREF:
		n := n.(*ir.StarExpr)
		l := safeExpr(n.X, init)
		if l == n.X {

	}
	if token.IsIdentifier(m) {
		cnt[m]++
		return
	}
	// Split up input.
	name, expr := splitNameExpr(m)
	if name != "" {
		cnt[name]++
	}
	if expr[0] != '(' || expr[len(expr)-1] != ')' {
		log.Fatalf("%s: non-compound expr in varCount1: %q", loc, expr)
	}
	s := split(expr[1 : len(expr)-1])
	for _, arg := range s[1:] {
		varCount1(loc, arg, cnt)
	}
}

	var inst *syntax.IndexExpr // function instantiation, if any
	if iexpr, _ := call.Fun.(*syntax.IndexExpr); iexpr != nil {
		if check.indexExpr(x, iexpr) {
			// Delay function instantiation to argument checking,
			// where we combine type and value arguments for type
			// inference.
			assert(x.mode == value)
			inst = iexpr
		}
		x.expr = iexpr
		check.record(x)
	} else {
		check.exprOrType(x, call.Fun, true)

	case *types.Struct:
		texpr := TypeExpr(f, pkg, typ) // typ because we want the name here.
		if texpr == nil {
			return nil
		}
		return &ast.CompositeLit{
			Type: texpr,
		}
	}
	return nil
}

// IsZeroValue checks whether the given expression is a 'zero value' (as determined by output of
// analysisinternal.ZeroValue)
func IsZeroValue(expr ast.Expr) bool {
	switch e := expr.(type) {

	for {
		// check if we have a pointer type
		// if pexpr, _ := typ.(*ast.StarExpr); pexpr != nil {
		if pexpr, _ := typ.(*syntax.Operation); pexpr != nil && pexpr.Op == syntax.Mul && pexpr.Y == nil {
			// if we've already seen a pointer, we're done
			if ptr {
				return false, nil
			}
			ptr = true
			typ = syntax.Unparen(pexpr.X) // continue with pointer base type
		}

		// var decl w/o init expr
		if s.Type == nil {
			check.error(s, code, "missing type or init expr")
		}
	case l < r:
		if l < len(s.Values) {
			// init exprs from s
			n := s.Values[l]
			check.errorf(n, code, "extra init expr %s", n)
			// TODO(gri) avoid declared and not used error here
		} else {
			// init exprs "inherited"
			check.errorf(s, code, "extra init expr at %s", check.fset.Position(init.Pos()))

import org.codehaus.groovy.ast.expr.ListExpression;
import org.codehaus.groovy.ast.expr.MapEntryExpression;
import org.codehaus.groovy.ast.expr.MapExpression;
import org.codehaus.groovy.ast.expr.MethodCallExpression;
import org.codehaus.groovy.ast.expr.MethodPointerExpression;
import org.codehaus.groovy.ast.expr.NotExpression;
import org.codehaus.groovy.ast.expr.PostfixExpression;

			expr:               "'abc 123 def 123'.replace('123', '456', 1)",
			expectEsimatedCost: checker.CostEstimate{Min: 3, Max: 3},
			expectRuntimeCost:  3,
		},
		{
			name:               "split",
			expr:               "'abc 123 def 123'.split(' ')",
			expectEsimatedCost: checker.CostEstimate{Min: 3, Max: 3},
			expectRuntimeCost:  3,
		},
		{
			name:               "split with limit",