When two files each declared a same-named class with a same-named method
(e.g. `class Logger { void log(); }`), a call resolved to whichever
definition was indexed first — so a call in `b/svc` wrongly targeted
`a/svc`, mixing up that method's callers and blast radius.
The reported case was C++ instance calls, but the underlying pattern —
"multiple same-named candidates, pick the first-indexed, ignore the call
site's file" — lived in three resolution paths, each firing for a
different call shape and affecting different languages:
- `obj.log()` instance -> resolveMethodOnType (C++)
- `Logger.log()` class receiver -> matchMethodCall Strategy 1/2/3
(Python, TypeScript, Java, C#)
- `Logger::log()` qualified -> matchByQualifiedName (C++, Rust)
All five sites now share one helper, `preferCallSiteFile`, that prefers
a candidate declared in the call site's own file when a name is
ambiguous. It runs after the `preferredFqn` block in resolveMethodOnType,
so Java/Kotlin import disambiguation (#314) — whose target is
intentionally in another file — is unaffected. The helper is a no-op
when there are fewer than two candidates or none share the call site's
file, so the common single-definition case is unchanged.
Adds 8 tests under `Same-name method disambiguation (#1079)`: the
`preferCallSiteFile` contract, resolveMethodOnType precedence (including
a guard that an import FQN still beats the same-file preference),
`matchByQualifiedName` disambiguation, and end-to-end index tests for the
C++ instance, TypeScript static, and C++ qualified call shapes.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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