GitNexus/gitnexus/test/fixtures/lang-resolution/cpp-overload-int-long/service.cpp
Gergo Magyar 02fe4b2723 fix(cpp): suppress receiver-bound CALLS when integer-width overloads collide (U2)
C++ arity-metadata normalizes int, long, short, unsigned, size_t to
'int' so single-candidate flows like 'process(42L)' match a 'long'-
typed parameter via loose matching. But when both 'process(int)' and
'process(long)' coexist as method overloads, they both end up with
parameterTypes=['int'] in the registry, and pickOverload's narrowing
returns 2 candidates with no way to disambiguate. The previous code
picked candidates[0] arbitrarily, emitting a CALLS edge to the wrong
overload roughly half the time.

Fix:
- Add isOverloadAmbiguousAfterNormalization in overload-narrowing.ts
  that detects >1 candidate sharing identical parameterTypes sequences.
- Have pickOverload return a new OVERLOAD_AMBIGUOUS sentinel when this
  fires.
- In the receiver-bound-calls loop, when pickOverload signals ambiguity,
  suppress the edge AND add the site to handledSites so the late-stage
  emitReferencesViaLookup pass does not re-emit the pre-resolved
  reference. Without the handled-mark, the reference index still
  carries a toDef and emits the same wrong edge.

Graph schema has no ambiguous-target edge model, so emitting two
edges (one per candidate) would require a separate schema change.
Zero-edge is the only safe outcome.

Other languages: the ambiguity check is a precondition gate, not a
behavior change for normal narrowing. Languages whose normalizers do
not collapse distinct types into a single token (verified by grep
over *-arity-metadata.ts) will never produce >1 candidate with
identical parameterTypes from genuinely distinct declarations, so
the branch is effectively C++-only in practice.

Test: cpp-overload-int-long fixture asserts exactly .toBe(0) CALLS
edges. Count=1 = arbitrary pick (the bug); count>1 = unsupported
ambiguous-edge model. Mode-gated to REGISTRY_PRIMARY_CPP=1 — legacy
DAG has no OVERLOAD_AMBIGUOUS wiring; backporting is out of scope.

All 2105 resolver integration tests pass under registry-primary; all
139 cpp tests pass under both modes (3 negative tests skipped in
legacy as documented).
2026-05-13 08:59:14 +01:00

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C++

#include "service.h"
void Service::process(int x) {}
void Service::process(long x) {}