Description

Problem

Resolves

Quoted::as_expr parses through parse_statement_or_expression_or_lvalue, where the InternedLValue branch handled = but not op-assign (like +=), while the regular statement parser already supported op-assign. This created inconsistent parsing behavior across the two paths.

Summary

• Added op-assign parsing for InternedLValue in parse_statement_or_expression_or_lvalue.
• Updated the InternedLValue branch in parse_statement to support op-assign before fallback = error recovery.
• Changed next_is_op_assign visibility to pub(super) so both parser paths can reuse it.
• Added parser tests covering InternedLValue += 1 in both entry points.

Additional Context

• Scope is limited to parser consistency and tests.
• Targeted parser tests pass locally.
• Current branch still has unrelated pre-existing failures in full noirc_frontend test runs.

User Documentation

Check one:

• No user documentation needed.
• Changes in docs/ included in this PR.
• [For Experimental Features] Changes in docs/ to be submitted in a separate PR.

PR Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier (https://prettier.io/) and/or cargo fmt on default settings.