factory: createExportAssignment doesn't parenthesise all expressions with parsing restrictions

[ajafff]

TypeScript Version: 3.0.0-dev.20180621

Search Terms:

Code

import * as ts from 'typescript';
const n = ts.createExportAssignment(
            undefined,
            undefined,
            false,
            ts.createPropertyAccess(
                ts.createClassExpression(
                    undefined,
                    undefined,
                    undefined,
                    undefined,
                    [ts.createProperty(undefined, [ts.createToken(ts.SyntaxKind.StaticKeyword)], 'prop', undefined, undefined, ts.createLiteral('1'))],
                ),
                'prop',
            ),
        );
ts.createPrinter().printNode(ts.EmitHint.Unspecified, n, ts.createSourceFile('dummy.ts', '', ts.ScriptTarget.Latest));

Expected behavior:

export default (class {static prop = '1'}.prop);

Note that this also applies to export default (function() {}());

To fix this, parenthesizeDefaultExpression needs to use getLeftmostExpression to get the leading class or function expression.

Actual behavior:

Invalid code: export default class {static prop = '1'}.prop;

[mhegazy]

PRs welcomed