The auto-loaded prelude (iter 23.2 work-in-progress) injects
`class Eq` plus three primitive instances (Eq Int, Eq Bool, Eq Str)
into every workspace. Five workspace::tests assertions broke against
this new baseline:
- iter22b1_missing_method_fires_diagnostic
- instance_without_superclass_instance_fires
- instance_overriding_nonexistent_method_fires
Their fixtures redeclare `class Eq` (and `class Ord` in one case),
which now collides with the prelude. Renamed each fixture's
`Eq`/`eq` -> `TEq`/`teq` and `Ord`/`lt` -> `TOrd`/`tlt`, matching
the scheme already used in the two earlier-renamed test_22b2
fixtures. Method `ne` stays (does not collide). Assertion strings
in workspace.rs updated to match.
- iter22b1_workspace_with_no_classes_has_empty_registry
- iter22b1_instance_in_class_module_loads_clean
Their asserted registry counts assumed an otherwise-empty registry.
Rewritten to filter by `defining_module != "prelude"`: the property
is "no NON-prelude entries" / "exactly one fixture-owned entry",
not raw count.
Doc comments updated alongside each assertion change so the rationale
for TEq/TOrd (collision avoidance) is local. No production code
touched.
The mono pass re-runs synth on every fn body to recover residual class
constraints. build_workspace_env (delegating to build_check_env) leaves
env.types and env.ctor_index workspace-flat. The synth path for cross-
module Pattern::Ctor / Term::Ctor resolution depends on a per-module
shape — local-first lookup, then imports-fallback that produces a
qualified type name. Without the overlay, the local-flat hit short-
circuits the fallback and yields a bare type name, mismatching the
qualified scrutinee/pattern from the sibling path with
CheckError::PatternTypeMismatch.
Add a per-module overlay helper that clears and rebuilds both
env.types and env.ctor_index from the current module's Def::Type list
— mirroring check_in_workspace at lib.rs:1257-1287 — and apply it at
the two mono entry points that re-walk bodies: the Phase 3 rewrite
loop in monomorphise_workspace and collect_targets_workspace_wide.
Pinned by tests/mono_xmod_ctor_pattern.rs (e580f75); also unblocks
the latent E2E regressions nested_ctor_pattern_first_two_sum,
std_either_list_demo, and ordering_match_via_prelude_prints_1 that
surfaced once the typeclass gate in workspace_has_typeclasses flipped
to true.
`monomorphise_workspace` re-runs `synth` on every fn body to recover
residual class constraints; the env it uses is built by
`mono::build_workspace_env`, which delegates to `build_check_env` and
produces a workspace-flat `ctor_index` (every Def::Type ctor across
every module, keyed by bare ctor name → bare type name).
`check_in_workspace` (lib.rs:1247-1258) explicitly clears that flat
index after `build_check_env` and rebuilds it per-module so that
`Pattern::Ctor`'s local-first / imports-fallback resolution at
lib.rs:2486-2521 keeps the qualified-type-name comparison at
lib.rs:2526 intact: imports-fallback yields a qualified
`resolved_type_name` (`Mod.Type`), local-hit yields a bare one.
The mono pass never does the per-module overlay, so when a body in
module B pattern-matches a ctor `C` whose Def::Type lives in imported
module A, the workspace-flat index resolves `C` locally and yields the
bare type name. The scrutinee, however, was typed against the
qualified name, and the comparison fails with
`PatternTypeMismatch { ctor: "Cons", ty: "A.Type<...>" }`.
Surfaced by iter 23.2 Task 3, which adds `class Eq a` + Eq Int/Bool/Str
instances to the prelude. Pre-Task-3 the prelude is class-free, so
`workspace_has_typeclasses(ws) == false` and the mono pass early-outs
at `mono.rs:73`. Task 3 flips the gate; every workspace now traverses
bodies, which brings the latent bug to the surface for the
pre-existing `nested_ctor_pattern_first_two_sum` and
`std_either_list_demo` E2E tests.
Sibling regressions in the same family: `mono_xmod_qualified_ref.rs`
(env.imports not seeded), commit 13b36cc (env.globals not seeded for
self-recursive fns), commit 5c5180f (env.types / env.ctor_index not
seeded for user ADTs — the original "flat ctor_index" decision that
this bug now exposes as wrong-by-construction for cross-module ctor
pattern resolution).
The minimal fixture is two modules with five defs total:
test_mono_ctor_listmod (data List a = Nil | Cons a (List a)) and
test_mono_ctor_main (class Trivial a + instance Trivial Int + a fn
that pattern-matches Cons against the imported List<Int> + a main).
The test pins the inner cause: matches against the specific
`CheckError::PatternTypeMismatch` variant with the qualified
scrutinee type and bare ctor name, so it stays RED regardless of the
prelude's typeclass content.
Pins fieldtest finding B1 (docs/specs/2026-05-10-fieldtest-floats.md).
DESIGN.md and JOURNAL Floats.3 promise that pattern-matching on a
Float literal is hard-rejected at typecheck via
CheckError::FloatPatternNotAllowed, but the rejection only fires when
typecheck is reached directly. The full check pipeline runs
ailang_core::desugar::desugar_module first, and build_eq rewrites
Pattern::Lit { Literal::Float } arms into (== scrutinee 1.5_FLOAT)
before typecheck — so the existing iter-3.4 reject arm at lib.rs:2316
is unreachable on input flowing through check / check_module /
check_workspace.
The existing reject_float_pattern_in_match test in builtins.rs calls
synth(...) directly on a hand-built Term::Match, bypassing desugar; it
passes today but does not protect the spec'd property. This new test
exercises check(&m) end-to-end and asserts the FloatPatternNotAllowed
error — currently fails because check returns Ok(CheckedModule).
GREEN side handed off to skills/implement mini-mode.
Brummel