[clang-tidy] Fix failing test after #80864

[sdkrystian]

The following test case in clang-tools-extra/test/clang-tidy/infrastructure/diagnostic.cpp is failing:

#ifdef PR64602 // Should not crash
template <class T = void>
struct S
{
    auto foo(auto);
};

template <>
auto S<>::foo(auto)
{
    return 1;
}
// CHECK8: error: template parameter list matching the non-templated nested type 'S<>' should be empty ('template<>') [clang-diagnostic-error]
#endif

#80864 fixes a bug where we would (incorrectly) append invented template parameters to empty template parameter lists, which causes this test to fail.

[llvmbot]

@llvm/pr-subscribers-clang-tidy

@llvm/pr-subscribers-clang-tools-extra

Author: Krystian Stasiowski (sdkrystian)

Changes

The following test case in clang-tools-extra/test/clang-tidy/infrastructure/diagnostic.cpp is failing:

#ifdef PR64602 // Should not crash
template <class T = void>
struct S
{
    auto foo(auto);
};

template <>
auto S<>::foo(auto)
{
    return 1;
}
// CHECK8: error: template parameter list matching the non-templated nested type 'S<>' should be empty ('template<>') [clang-diagnostic-error]
#endif

#80864 fixes a bug where we would (incorrectly) append invented template parameters to empty template parameter lists, which causes this test to fail.

---

Full diff: https://github.com/llvm/llvm-project/pull/81171.diff

1 Files Affected:

• (modified) clang-tools-extra/test/clang-tidy/infrastructure/diagnostic.cpp (+2-1)

diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/diagnostic.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/diagnostic.cpp
index 547f634a101c58..d0efc5ca763753 100644
--- a/clang-tools-extra/test/clang-tidy/infrastructure/diagnostic.cpp
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/diagnostic.cpp
@@ -68,5 +68,6 @@ auto S<>::foo(auto)
 {
     return 1;
 }
-// CHECK8: error: template parameter list matching the non-templated nested type 'S<>' should be empty ('template<>') [clang-diagnostic-error]
+// CHECK8: error: conflicting types for 'foo' [clang-diagnostic-error]
+// CHECK8: note: previous declaration is here
 #endif

[erichkeane]

This seems right to me, though a 2nd reviewer would be nice. I don't think we should wait for CI on this due to it fixing a bot-breakage.

[PiotrZSL]

LGTM, purpose of this test is just to verify that errors (any) are shown in clang-tidy

[sdkrystian]

@erichkeane I'm building the check-clang-extra target locally just to make sure that the test passes... should be done in ~5 mins