[nullability] Fix crash on function template calls that only deduce some arguments.
PiperOrigin-RevId: 527531959
diff --git a/nullability_verification/pointer_nullability_analysis.cc b/nullability_verification/pointer_nullability_analysis.cc
index e4a4729..946fa11 100644
--- a/nullability_verification/pointer_nullability_analysis.cc
+++ b/nullability_verification/pointer_nullability_analysis.cc
@@ -173,7 +173,18 @@
if (auto* DRE =
dyn_cast<DeclRefExpr>(CE->getCallee()->IgnoreImpCasts());
DRE != nullptr && ST->getReplacedParameter()->getDepth() == 0 &&
- DRE->hasExplicitTemplateArgs()) {
+ // Some or all of the template arguments may be deduced, and we
+ // won't see those on the `DeclRefExpr`. If the template argument
+ // was deduced, we don't have any sugar for it.
+ // TODO: Can we somehow obtain it from the function param it was
+ // deduced from?
+ // TODO: This check, as well as the index into `template_arguments`
+ // below, may be incorrect in the presence of parameters packs.
+ // In function templates, parameter packs may appear anywhere in the
+ // parameter list. The index may therefore refer to one of the
+ // pack arguments, but we might incorrectly interpret it as
+ // referring to an argument that follows the pack.
+ ST->getIndex() < DRE->template_arguments().size()) {
TypeSourceInfo* TSI =
DRE->template_arguments()[ST->getIndex()].getTypeSourceInfo();
if (TSI == nullptr) return std::nullopt;
diff --git a/nullability_verification/test/function_calls.cc b/nullability_verification/test/function_calls.cc
index effa853..e64a6da 100644
--- a/nullability_verification/test/function_calls.cc
+++ b/nullability_verification/test/function_calls.cc
@@ -435,6 +435,14 @@
)cc"));
}
+TEST(PointerNullabilityTest, CallFunctionTemplate_PartiallyDeduced) {
+ EXPECT_TRUE(checkDiagnostics(R"cc(
+ template <int, class T>
+ T f(T);
+ void target() { f<0>(1); }
+ )cc"));
+}
+
} // namespace
} // namespace nullability
} // namespace tidy
