C4: Contract verifier — Z3-backed verification#10
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Implements Tier 1 contract verification using Z3 SMT solver. Functions with decidable contracts (linear integer arithmetic, comparisons, Boolean logic, if/else) are proved automatically. Unsupported constructs (match, effects, recursion, quantifiers) fall back to Tier 3 with a warning. Counterexample generation shows concrete inputs that break violated contracts. New modules: vera/smt.py (AST→Z3 translation), vera/verifier.py (verification orchestration). New CLI command: vera verify <file>. 51 new tests (335 total). Version 0.0.8. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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…ecks The four `in`/`not in` substring assertions on mono-suffix strings in `TestGenericMonoSuffixFromSlotRef604` could pass on longer symbol variants (e.g. `$option_map$Int_Int_X` would satisfy `"$option_map$Int_Int" in wat`). No current code path produces longer variants, but the assertions weren't precise about what they were pinning. Replaced each substring check with a boundary-safe regex using a negative lookahead: `re.search(r"\$option_map\$<suffix>(?![A-Za-z0-9_])", wat)`. The pattern rejects any continuation character that would indicate a longer variant. `re` was already imported at top of file. Two test methods updated: - `test_mono_suffix_correct_for_slotref_fn_alias_arg` — positive `$option_map$Int_Int` + negative `$option_map$Int_Bool` - `test_parameterised_alias_substitutes_type_args` — positive `$option_map$Int_Int` + negative `$option_map$T_T` Validation: all 4 tests in `TestGenericMonoSuffixFromSlotRef604` pass against current compiler output. Refs #604 #655 #659 Co-Authored-By: Claude <noreply@anthropic.invalid>
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Summary
requires/ensuresclauses — Tier 1 (decidable fragment: QF_LIA + Boolean logic +length) proved automatically, Tier 3 (unsupported constructs) warned gracefullyvera/smt.py(AST→Z3 translation layer),vera/verifier.py(verification orchestration)vera verify <file>— type-checks then verifies contracts, prints tier summaryWhat it verifies
safe_divide.veraabsolute_value.veramodules.vera(clamp)factorial.veragenerics.veraincrement.veraTest plan
pytest tests/ -v— 335 passedmypy vera/— no issues (11 source files)python scripts/check_version_sync.py— 0.0.8 consistentpython scripts/check_examples.py— all 13 examples pass (check + verify)python scripts/check_spec_examples.py— 154 spec blocks valid🤖 Generated with Claude Code