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Untested compiler error and warning variants

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Active
Tech stack
javascript
Domain
testing

Research direction

Start with tests/ERROR_VARIANTS.md and the super_errors harnesses it describes. The issue lists compiler error and warning variants that lack test coverage, along with the obstacles found for reproducing them. Determine which entries can be covered by fixtures or need a different harness, then add tests where reachable and document any dead-code candidates; done means the useful catalog findings are preserved and the test gaps are addressed.

Written by the indexing model from the issue text.

Description

tests/ERROR_VARIANTS.md is being removed. This issue keeps the useful part: the compiler error and warning variants that no test exercises. For each one it records what the catalog found about reaching it.

Possibly a bug

  • Syntaxerr.Variable_in_scope: reachable via let f: type t. (t, 't) => t = …, but Syntaxerr.error has no registered printer, so it escapes as Fatal error: exception Syntaxerr.Error(_). It needs a printer, or should become a regular typed diagnostic.

Reachability unknown

Sites are live, but no source reproduction has been found. Each of these either needs a fixture or is a dead-code candidate.

  • typedecl.Cycle_in_def: recursive_type_abbrev_cycle.res reports Recursive_abbrev instead.
  • typedecl.Rebind_mismatch: the shape check after Rebind_wrong_type.
  • typedecl.Type_clash: marked "appears dead" in the source.
  • typemod.With_makes_applicative_functor_ill_typed (check_usage_of_path_of_substituted_item): attempts hit not a signature first.
  • typemod.Cannot_eliminate_dependency (Pmod_apply in type_module_aux): attempts hit Incomplete_packed_module or escapes its scope.
  • typemod.Scoping_pack (type_package): attempts hit Incomplete_packed_module.
  • Warning 5 Partial_application (check_application_result): no reproduction found.

Reachable, but not from the super_errors harnesses

Needs a per-fixture flag
  • typecore.Jsx_not_enabled: the runner hard-codes -bs-jsx 4.
  • typecore.Invalid_string_escape_sequence: the parser rejects such source first, so only a PPX can produce the AST.
Needs missing or stale build state
  • typedecl.Unavailable_type_constructor
  • typemod.With_changes_module_alias
  • typemod.Cannot_scrape_alias
  • typetexp.Cannot_scrape_alias
  • includemod.Unbound_modtype_path
  • includemod.Unbound_module_path
  • includemod.Invalid_module_alias
  • bs_exception.Cmj_not_found
  • bs_exception.Missing_ml_dependency
  • bs_exception.Dependency_script_module_dependent_not: a script-mode dependency used from package mode.
  • env.Illegal_renaming
  • env.Inconsistent_import
  • env.Missing_module
  • Warning 49 No_cmi_file
Needs corrupt or foreign binary files
  • cmi_format.Not_an_interface
  • cmi_format.Wrong_version_interface
  • cmi_format.Corrupted_interface
  • cmt_format_common.Not_a_typedtree
  • cmd_ast_exception.WrongMagic: a PPX returns the wrong AST magic number.
Needs custom argv
  • bsc_args.Unknown (bsc --bogus)
  • bsc_args.Missing (bsc -o)

Reachable from plain source

  • Warning 27 Unused_var_strict: no expected output shows it.
Dominant language
ReScript
Stars
7.5k
Forks
483
Avg merge
1d 2h
Merged PRs (30d)
150

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