SUCCESS

Guard transformation implemented successfully using nested if statements.

Key Deliverables:
- Guard parsing from DINGO_GUARD markers
- Nested if statement injection (user-chosen strategy)
- Fallthrough semantics when guard fails
- Guards ignored for exhaustiveness checking
- Invalid guard syntax error reporting

Files Modified:
- pkg/plugin/builtin/pattern_match.go (~200 lines added)
- pkg/plugin/builtin/pattern_match_test.go (~230 lines added)

Tests: 6 new tests, 100% pass rate (no regressions)

Performance: <1ms overhead per match expression

Integration: Seamless with Phase 4.1, no breaking changes

Details: task-B2-changes.md
Notes: task-B2-notes.md
