pi := math.Pi
	fmt.Printf("%v %g %.2f (%6.2f) %e\n", pi, pi, pi, pi, pi)
	// Result: 3.141592653589793 3.141592653589793 3.14 (  3.14) 3.141593e+00

	// Complex numbers format as parenthesized pairs of floats, with an 'i'
	// after the imaginary part.
	point := 110.7 + 22.5i
	fmt.Printf("%v %g %.2f %.2e\n", point, point, point, point)
	// Result: (110.7+22.5i) (110.7+22.5i) (110.70+22.50i) (1.11e+02+2.25e+01i)

			continue
		}
		if first == nil {
			first = gen
			continue // Don't touch the first one.
		}
		// We now know there is more than one package in this import
		// declaration. Ensure that it ends up parenthesized.
		first.Lparen = first.Pos()
		// Move the imports of the other import declaration to the first one.
		for _, spec := range gen.Specs {
			spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()

		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 )"

must be <a href="#Uniqueness_of_identifiers">unique</a>.
If absent, each type stands for one item of that type.
Parameter and result
lists are always parenthesized except that if there is exactly
one unnamed result it may be written as an unparenthesized type.
</p>

<p>
The final incoming parameter in a function signature may have
a type prefixed with <code>...</code>.