}
	case ir.ODEREF:
		n := n.(*ir.StarExpr)
		return s.exprPtr(n.X, n.Bounded(), n.Pos())
	case ir.ODOT:
		n := n.(*ir.SelectorExpr)
		p := s.addr(n.X)
		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
	case ir.ODOTPTR:
		n := n.(*ir.SelectorExpr)
		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
	case ir.OCONVNOP:
		n := n.(*ir.ConvExpr)

	switch t := x.(type) {
	case *ast.Ident:
		return t.Name, false
	case *ast.IndexExpr:
		return baseTypeName(t.X)
	case *ast.IndexListExpr:
		return baseTypeName(t.X)
	case *ast.SelectorExpr:
		if _, ok := t.X.(*ast.Ident); ok {
			// only possible for qualified type names;
			// assume type is imported
			return t.Sel.Name, true
		}
	case *ast.ParenExpr:
		return baseTypeName(t.X)

		}
		x.typ = Typ[Uintptr]

	case _Offsetof:
		// unsafe.Offsetof(x T) uintptr, where x must be a selector
		// (no argument evaluated yet)
		arg0 := argList[0]
		selx, _ := ast.Unparen(arg0).(*ast.SelectorExpr)
		if selx == nil {
			check.errorf(arg0, BadOffsetofSyntax, invalidArg+"%s is not a selector expression", arg0)
			check.use(arg0)
			return
		}

		check.expr(nil, x, selx.X)
		if x.mode == invalid {

		// Resulting in an untyped constant (e.g., built-in complex).
		// The respective calls take care of calling updateExprType
		// for the arguments if necessary.

	case *syntax.Name, *syntax.BasicLit, *syntax.SelectorExpr:
		// An identifier denoting a constant, a constant literal,
		// or a qualified identifier (imported untyped constant).
		// No operands to take care of.

	case *syntax.ParenExpr:

	// but at least check that it's *M or *something.M.
	// Same applies for B, F and T.
	if name, ok := ptr.X.(*ast.Ident); ok && name.Name == arg {
		return true
	}
	if sel, ok := ptr.X.(*ast.SelectorExpr); ok && sel.Sel.Name == arg {
		return true
	}
	return false
}

// isTest tells whether name looks like a test (or benchmark, according to prefix).

		}
		x.typ = Typ[Uintptr]

	case _Offsetof:
		// unsafe.Offsetof(x T) uintptr, where x must be a selector
		// (no argument evaluated yet)
		arg0 := argList[0]
		selx, _ := syntax.Unparen(arg0).(*syntax.SelectorExpr)
		if selx == nil {
			check.errorf(arg0, BadOffsetofSyntax, invalidArg+"%s is not a selector expression", arg0)
			check.use(arg0)
			return
		}

		check.expr(nil, x, selx.X)
		if x.mode == invalid {

// typeHashFieldOf returns an expression to select the type hash field
// from an interface's descriptor word (whether a *runtime._type or
// *runtime.itab pointer).
func typeHashFieldOf(pos src.XPos, itab *ir.UnaryExpr) *ir.SelectorExpr {
	if itab.Op() != ir.OITAB {
		base.Fatalf("expected OITAB, got %v", itab.Op())
	}
	var hashField *types.Field
	if itab.X.Type().IsEmptyInterface() {
		// runtime._type's hash field

	"_Ctype_",
	"_Cvar_", // actually a pointer to the var
	"_Cfpvar_fp_",
	"_Cfunc_",
	"_Cmacro_", // function to evaluate the expanded expression
}

func (check *Checker) selector(x *operand, e *syntax.SelectorExpr, def *TypeName, wantType bool) {
	// these must be declared before the "goto Error" statements
	var (
		obj      Object
		index    []int
		indirect bool
	)

	sel := e.Sel.Value

	}
	args := call.Args
	if len(args) <= firstArg {
		// Skip calls without variadic args.
		return
	}
	args = args[firstArg:]

	if firstArg == 0 {
		if sel, ok := call.Args[0].(*ast.SelectorExpr); ok {
			if x, ok := sel.X.(*ast.Ident); ok {
				if x.Name == "os" && strings.HasPrefix(sel.Sel.Name, "Std") {

	"_Ctype_",
	"_Cvar_", // actually a pointer to the var
	"_Cfpvar_fp_",
	"_Cfunc_",
	"_Cmacro_", // function to evaluate the expanded expression
}

func (check *Checker) selector(x *operand, e *ast.SelectorExpr, def *TypeName, wantType bool) {
	// these must be declared before the "goto Error" statements
	var (
		obj      Object
		index    []int
		indirect bool
	)

	sel := e.Sel.Name