The fix correctly identifies that variables bound inside nominal
patterns (like `s` in `Container.Box(s)`) are bound in the pattern
scope and don't need to be captured. This results in cleaner
canonical IR where functions that use nominal pattern matching
are now represented as pure lambdas instead of closures with
unnecessary captures.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>