Class GenericTemplateMember

java.lang.Object
org.ek9lang.compiler.support.GenericTemplateMember
public final class GenericTemplateMember extends Object
THE mapping from a member of a MONOMORPHISED parameterised type back to the member of the GENERIC it was substituted from. Use it wherever a parameterisation must be attributed to the source a developer actually wrote; do not re-derive it.

Why this exists. EK9 monomorphises, so Box of String and Box of Integer are separate aggregates whose members are substituted COPIES of the generic's. Every tool that reasons about "the code" wants the one source, not the N copies — and three separate surfaces were found (2026-09-13) to have lost sight of generics for exactly this reason:

  • Coverage (D11) — probes were numbered per monomorphisation, so one source constructor acquired an identity per parameterisation and inflated the denominator.
  • Input variety (D11/W5a) — the phase-9 floor is squirrelled on the TEMPLATE, but a parameterisation's members are copies made at resolution, so they never received it and no probe was emitted inside a generic at all.
  • Reachability (D15) — the call graph enumerated template members while its edges targeted monomorphised ones, so a USED generic's methods were reported as dead code.

🔑 Correspondence is by SOURCE TOKEN — the declaration position — never by name or arity. Symbol.copy carries setSourceToken(this.getSourceToken()) through substitution, so a substituted member and its template share a position exactly. Name-and-arity cannot be used: a constructor's name IS its type's name, which is mangled in the copy and not in the template, and a generic may declare Box(T) beside Box(String) so arity is ambiguous. Matching those wrongly is silent — it attributes work to the wrong member rather than failing.

Stateless; every method is static and null-tolerant.

  • Method Details

    • forMethod

      public static Optional<MethodSymbol> forMethod(MethodSymbol method)
      The generic's own method this one was substituted from.
      Parameters:
      method - the method being examined; may be null
      Returns:
      the template's corresponding method, or empty when method is not a member of a parameterised type (which includes every ordinary, non-generic method)