Own nonzero trailing sentinels in canonical string-backed snapshots and preserve specialization identity across computed and direct views.
Verified: bro build; bro test (296 passed); python3 tests/native.py (1026 interpreter/native comparisons at -O0/-O2, 5 native allocator programs, LLVM output and CLI errors).
Reuse canonical matches for optional presence and exact by-value payload captures across checking, lowering and compile-time selection.
Snapshot the optional-match flag before selector construction: AST additions can reallocate storage and invalidate the borrowed tree until refresh.
Verified 268 bootstrap tests and 908 interpreter/native programs at -O0 and -O2, plus native allocator, LLVM and CLI checks.
Reuse checked match selection for generic constant subjects and explicit match $(). Preserve owned captures, runtime scope and control transfers; keep ordinary calls, mutable subjects and potential runtime defaults unprobed. Update README and TODO checkpoint boundaries.
Verified: bro build; bro test (250 passed); python3 tests/native.py (555 interpreter/native comparisons at -O0/-O2, allocator, LLVM and CLI checks); direct interpreter/native constant-match smoke (42).
Preserve resolver failures on synthetic selector captures before elaborating payloads; selector bodies omit the original capture uses.
Verified bro build, bro test (250 passed), and tests/native.py (536 interpreter/native programs at -O0 and -O2, allocator, LLVM and CLI checks).
hl-valdemar