func fixAtPosCall(f *ast.File) {
	ast.Inspect(f, func(n ast.Node) bool {
		switch n := n.(type) {
		case *ast.CallExpr:
			if selx, _ := n.Fun.(*ast.SelectorExpr); selx != nil && selx.Sel.Name == "dump" {
				for i, arg := range n.Args {
					if call, _ := arg.(*ast.CallExpr); call != nil {
						// rewrite xxx.dump(..., atPos(x), ...) to xxx.dump(..., x.Pos(), ...)
						if isIdent(call.Fun, "atPos") {

	x = astutil.Unparen(x) // ignore parens on rhs

	if _, ok := x.(*ast.CompositeLit); ok {
		return nil
	}
	if _, ok := x.(*ast.CallExpr); ok {
		// A call may return a zero value.
		return nil
	}
	if star, ok := x.(*ast.StarExpr); ok {
		if _, ok := astutil.Unparen(star.X).(*ast.CallExpr); ok {
			// A call may return a pointer to a zero value.
			return nil
		}
	}

}

// isFuzzTargetDotFuzz reports whether call is (*testing.F).Fuzz().
func isFuzzTargetDotFuzz(pass *analysis.Pass, call *ast.CallExpr) bool {
	return isFuzzTargetDot(pass, call, "Fuzz")
}

// isFuzzTargetDotAdd reports whether call is (*testing.F).Add().
func isFuzzTargetDotAdd(pass *analysis.Pass, call *ast.CallExpr) bool {
	return isFuzzTargetDot(pass, call, "Add")
}

// isFuzzTargetDot reports whether call is (*testing.F).<name>().

		left, right = n.X, n.Y
	}

	// Recognize m[k] = append(m[k], ...) so we can reuse
	// the mapassign call.
	var mapAppend *ir.CallExpr
	if left.Op() == ir.OINDEXMAP && right.Op() == ir.OAPPEND {
		left := left.(*ir.IndexExpr)
		mapAppend = right.(*ir.CallExpr)
		if !ir.SameSafeExpr(left, mapAppend.Args[0]) {
			base.Fatalf("not same expressions: %v != %v", left, mapAppend.Args[0])
		}
	}

		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)
				}

		} 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,

// reports whether the call is valid, with *x holding the result;
// but x.expr is not set. If the call is invalid, the result is
// false, and *x is undefined.
func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ bool) {
	argList := call.Args

	// append is the only built-in that permits the use of ... for the last argument
	bin := predeclaredFuncs[id]
	if hasDots(call) && id != _Append {

func (r *rewriter) editDefer(x *syntax.CallStmt) syntax.Stmt {
	if r.defers == nil {
		// Declare and initialize the #defers token.
		init := &syntax.CallExpr{
			Fun: runtimeSym(r.info, "deferrangefunc"),
		}
		tv := syntax.TypeAndValue{Type: r.any.Type()}
		tv.SetIsValue()
		init.SetTypeInfo(tv)
		r.defers = r.declVar("#defers", r.any.Type(), init)
	}