}

	// Constant.
	haveConstant := false
	switch tok.ScanToken {
	case scanner.Int, scanner.Float, scanner.String, scanner.Char, '+', '-', '~':
		haveConstant = true
	case '(':
		// Could be parenthesized expression or (R). Must be something, though.
		tok := p.next()
		if tok.ScanToken == scanner.EOF {
			p.errorf("missing right parenthesis")
			return
		}
		rname := tok.String()
		p.back()

}

// An LParen represents the beginning of a parenthesized line block.
// It is a place to store suffix comments.
type LParen struct {
	Comments
	Pos Position
}

func (x *LParen) Span() (start, end Position) {
	return x.Pos, x.Pos.add(")")
}

// An RParen represents the end of a parenthesized line block.
// It is a place to store whole-line (before) comments.

			// *(T)
			p.syntaxError("cannot parenthesize embedded type")
			p.next()
			typ = p.qualifiedName(nil)
			p.got(_Rparen) // no need to complain if missing
		} else {
			// *T
			typ = p.qualifiedName(nil)
		}
		tag := p.oliteral()
		p.addField(styp, pos, nil, newIndirect(pos, typ), tag)

	case _Lparen:
		p.syntaxError("cannot parenthesize embedded type")
		p.next()
		var typ Expr

		return "key/value association"
	case *ast.LabeledStmt:
		return "statement label"
	case *ast.MapType:
		return "map type"
	case *ast.Package:
		return "package"
	case *ast.ParenExpr:
		return "parenthesized " + NodeDescription(n.X)
	case *ast.RangeStmt:
		return "range loop"
	case *ast.ReturnStmt:
		return "return statement"
	case *ast.SelectStmt:
		return "select statement"
	case *ast.SelectorExpr:

		p.lex()
		if p.tok == "!" {
			panic(&SyntaxError{Offset: p.pos, Err: "double negation not allowed"})
		}
		return not(p.atom())
	}
	return p.atom()
}

// atom parses a tag or a parenthesized expression.
// On entry, the next input token HAS been lexed.
// On exit, the next input token has been lexed and is in p.tok.
func (p *exprParser) atom() Expr {
	// first token already in p.tok
	if p.tok == "(" {

		x := &ast.BasicLit{ValuePos: p.pos, Kind: p.tok, Value: p.lit}
		p.next()
		return x

	case token.LPAREN:
		lparen := p.pos
		p.next()
		p.exprLev++
		x := p.parseRhs() // types may be parenthesized: (some type)
		p.exprLev--
		rparen := p.expect(token.RPAREN)
		return &ast.ParenExpr{Lparen: lparen, X: x, Rparen: rparen}

	case token.FUNC:
		return p.parseFuncTypeOrLit()
	}

		return check.instantiatedType(e.X, syntax.UnpackListExpr(e.Index), def)

	case *syntax.ParenExpr:
		// Generic types must be instantiated before they can be used in any form.
		// Consequently, generic types cannot be parenthesized.
		return check.definedType(e.X, def)

	case *syntax.ArrayType:
		typ := new(Array)
		setDefType(def, typ)
		if e.Len != nil {
			typ.len = check.arrayLength(e.Len)
		} else {
			// [...]array

		return check.instantiatedType(ix, def)

	case *ast.ParenExpr:
		// Generic types must be instantiated before they can be used in any form.
		// Consequently, generic types cannot be parenthesized.
		return check.definedType(e.X, def)

	case *ast.ArrayType:
		if e.Len == nil {
			typ := new(Slice)
			setDefType(def, typ)
			typ.elem = check.varType(e.Elt)
			return typ
		}

func identity[T any](x T) T { return x }

func _[_ any](x int) int { panic(0) }
func _[T any](T /* ERROR "redeclared" */ T)() {}
func _[T, T /* ERROR "redeclared" */ any]() {}

// Constraints (incl. any) may be parenthesized.
func _[_ (any)]() {}
func _[_ (interface{})]() {}

func reverse[T any](list []T) []T {
        rlist := make([]T, len(list))
        i := len(list)
        for _, x := range list {
                i--

	_, err = parser.ParseFile(fset, "", got, 0)
	if err != nil {
		t.Errorf("%v\norig: %q\ngot : %q", err, src, got)
	}
}

// If a declaration has multiple specifications, a parenthesized
// declaration must be printed even if Lparen is token.NoPos.
func TestParenthesizedDecl(t *testing.T) {
	// a package with multiple specs in a single declaration
	const src = "package p; var ( a float64; b int )"