Printer doesn't parenthesize untyped rest arguments in function type literals

[DanielRosenwasser]

TypeScript Version: 2.3.2

Code

import ts = require("typescript");

function getAnyFunctionTypeNode() {
    const param = ts.createParameter(
        /*decorators*/ undefined,
        /*modifiers*/ undefined,
        ts.createToken(ts.SyntaxKind.DotDotDotToken),
        "args");

    const result = ts.createFunctionTypeNode(
            /*typeParameters*/ undefined,
            /*parameters*/[param],
            /*type*/ ts.createKeywordTypeNode(ts.SyntaxKind.AnyKeyword));
    return result;
}

const node = getAnyFunctionTypeNode();
const file = ts.createSourceFile("foo.ts", "", ts.ScriptTarget.Latest, /*setParentNodes*/ false, ts.ScriptKind.TS);
const output = ts.createPrinter().printNode(ts.EmitHint.Unspecified, node, file);
console.log(output);

Expected behavior:

Console logs the following:

(...args) => any

Actual behavior:

Console logs the following:

...args => any