Pattern-matching test coverage (matching.ml / parmatch.ml)#4
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First batch of fixtures targeting uncovered branches in compiler/ml/matching.ml (pattern compilation to lambda). Covers `combine_constant` across every constant kind, each routed to a distinct compilation strategy: - Const_int -> call_switcher (interval edges, holes, negatives) - Const_char -> call_switcher - Const_float -> make_test_sequence with Pfloatcomp - Const_bigint -> make_test_sequence with Pbigintcomp Runtime-asserted via Mocha so the suite stays portable across alternative bsc implementations. Signed-off-by: Jono Prest <jono@envio.dev> Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
…ts, records, arrays, or-patterns)
Second batch of portable runtime-behavior fixtures targeting uncovered
branches in compiler/ml/matching.ml:
- constructors: exhaustive variant Lswitch, extension/exception
constructors (Pextension_slot_eq), unboxed single constructor
- polyvariant: const + block tags (Pis_poly_var_block split, both
variant switchers)
- record/tuple: field projection, mutable fields, `if` guards
- array: dispatch by length
- or-patterns: constant-constructor or, shared-variable or-binding,
or-patterns inside tuple columns (explode_or_pat / precompile_or)
All matches exhaustive (warning-clean under -warn-error A); 942 mocha
tests pass.
Signed-off-by: Jono Prest <jono@envio.dev>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Apply `make format` to pattern_match_array_test.res and commit the generated .mjs for all pattern-match fixtures, matching the repo convention of checking in tests/tests compiled output. Signed-off-by: Jono Prest <jono@envio.dev> Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
float/bigint/char matches now have >= 4 cases, so make_test_sequence exercises split_sequence/cut (the binary-search comparison tree in matching.ml) rather than only the flat comparison chain. Signed-off-by: Jono Prest <jono@envio.dev> Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
…ines) Add tests/PATTERN_MATCHING_COVERAGE.md cataloguing, for matching.ml and parmatch.ml, which uncovered lines are structurally unreachable (dead OCaml-bytecode string-search tree, int32/64 asserts, `when false` guards, `if dbg` debug printers, defensive fatal_error/assert) versus reachable-but-cold edges worth fixtures (witness pretty-printers, All_clauses_guarded, lub, dichotomic comparison split, partial-match failaction paths). Companion to ERROR_VARIANTS.md. Signed-off-by: Jono Prest <jono@envio.dev> Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Target parmatch.ml analysis paths and matching.ml partial-match
compilation via non-exhaustive / redundant matches:
- non_exhaustive_{tuple,list,record,variant,polyvariant,array}: drive
the per-shape witness pretty-printers (pretty_val) that render the
"you forgot to handle" counter-example
- non_exhaustive_{int,char,string,float,bigint}: drive pretty_const
for each scalar witness
- all_clauses_guarded: Warnings.All_clauses_guarded
- redundant_or_branch: Upartial (partially-redundant or-pattern)
- overlapping_or_lub: least-upper-bound of overlapping or-branches
Snapshots generated via `node input.js update`; verify run passes.
Signed-off-by: Jono Prest <jono@envio.dev>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Cross-reference PATTERN_MATCHING_COVERAGE.md and the new non_exhaustive_* / redundancy fixtures from the Warnings section of ERROR_VARIANTS.md; apply `make format` to the constants fixture comment. Signed-off-by: Jono Prest <jono@envio.dev> Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
…ess printer Direct per-fixture BISECT_FILE measurement showed parmatch.ml's pretty_val/pretty_const family (~364-434) stays cold even when a non-exhaustive witness prints: the user-facing witness is rendered by Pattern_printer.print_pattern (compiler/common, already ~88% covered), not by these debug printers. Move them to the dead-code table. Also record the measured contribution of this PR's fixtures (~10 lines in matching.ml from the dichotomic split, ~5 in parmatch.ml from All_clauses_guarded/Upartial) and note the matching.ml partial-match paths remain cold (simple non-exhaustive matches don't reach them). Signed-off-by: Jono Prest <jono@envio.dev> Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Goal
Lift test coverage of the two most central, correctness-critical pattern-matching files in the compiler, using portable
.resfixtures so alternativebscimplementations can run the same suite.Baseline (fresh
make coverageoffmaster):compiler/ml/matching.ml— 72.6% (pattern → lambda compilation)compiler/ml/parmatch.ml— 75.6% (exhaustiveness / redundancy analysis)Approach
Split by what's portable:
matching.ml→ runtime-behavior fixtures intests/tests/src/*_test.res(Mochaeq(__LOC__, …)), fully implementation-agnostic. Compiles under-warn-error A, so all matches are exhaustive.parmatch.ml→ warning snapshots intests/build_tests/super_errors/(these also emit JS, so they exercisematching.mlpartial-match paths too).Targets were derived from line-level coverage + reading the source, excluding genuinely unreachable branches (e.g.
expand_stringswitch— the JS backend emitsLstringswitchinstead;Const_int32/64assert false;when falseguards;if dbgdebug code). Those will be documented as unreachable rather than chased.Planned fixture matrix
matching.mlbehavior (tests/tests/src/)pattern_match_constants_test—combine_constant: int/char (call_switcher), float/bigint (make_test_sequence)pattern_match_intswitch_test— dense vs sparse int intervals (edges/holes)pattern_match_constructors_test— variant arity 0/1/N, unboxed, extension constructorspattern_match_polyvariant_test— const-tag + block-tag polymorphic variantspattern_match_record_tuple_test— immutable/mutable/optional-field/inlined records, tuplespattern_match_array_test— match by lengthpattern_match_orpat_test— nested or-patterns, or-pats binding vars / under constructorsparmatch.mlanalysis (super_errors/)lub(w11)super_errors_multi/)Draft — pushing fixtures incrementally. Coverage lift will be re-measured at the end.
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