LoweringEq

Generate equalsData after converting both values to their Data representation.

Generate repr-specific equality comparison.

Dispatches based on resolved type and representation; see LoweringEq doc for the dispatch order.

Generate Case-based field comparison for ProdUplcConstr values. Each field is extracted via genSelect and compared recursively.

Native equality for SumUplcConstr-represented values.

Emits letrec eqSum(a, b) = case a of ... where each variant branch matches b against the same variant tag (returning False on mismatch) and ANDs field comparisons. For fields whose substituted type matches the outer sum type, the recursive eqSum reference is used instead of recursing into a fresh generateEqualsForRepr (which would emit a duplicate letrec for self-referential types like List).

For non-recursive sums (e.g., Option) the letrec is harmless overhead — the function never references itself.

Check if this is a fully-applied FunctionalInterface call with known Eq semantics.

Check if this is equalsRepr(a, b) — the outer Apply of curried application. Handles both Apply(Apply(ExternalVar, a), b) and Apply(Apply(TypeApply(ExternalVar, A), a), b) (when type parameter is present).

Lower an Eq application using repr-specific equality.

The plugin annotates Apply nodes for FunctionalInterface types with "functionalInterfaceType". For Eq, we always inline an optimal comparison based on the argument representation instead of calling the Eq function. This is sound because every Eq instance is structurally consistent (a === b iff a.toData == b.toData) by construction: the compiler plugin rejects hand-written Eq lambdas at creation, so an instance can only come from Eq.derived (structural by generation) or Eq.structural(...) (an explicit assertion of structurality by the author). Non-structural types are excluded from the Eq system entirely (see RationalEq/AssocMapEq), and the non-structural combinators (Eq.by/orElse/orElseBy) are rejected in on-chain code (audit 2026-07-10 I1).

Lower equalsRepr(a, b) — picks the optimal comparison for the resolved types/reprs.