From fc84ebfff3a3dd373129f465f2ad5763ed4423c6 Mon Sep 17 00:00:00 2001
From: Evgeny Shulgin <izaronplatz@gmail.com>
Date: Mon, 14 Feb 2022 11:28:22 +0100
Subject: [PATCH] [clang-tidy] Ignore variable template partial specializations
 in `misc-definitions-in-headers`

Variable template partial specializations are inline and can't lead
to ODR-violations. The checker now ignores them.

Fixes https://github.com/llvm/llvm-project/issues/53519

Reviewed By: hokein

Differential Revision: https://reviews.llvm.org/D119098
---
 .../clang-tidy/misc/DefinitionsInHeadersCheck.cpp      |  3 +++
 .../checkers/misc-definitions-in-headers.hpp           | 10 ++++++++++
 2 files changed, 13 insertions(+)

diff --git a/clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp b/clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp
index 411d6db58243..9a7a7e108b12 100644
--- a/clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp
@@ -149,6 +149,9 @@ void DefinitionsInHeadersCheck::check(const MatchFinder::MatchResult &Result) {
     // Ignore inline variables.
     if (VD->isInline())
       return;
+    // Ignore partial specializations.
+    if (isa<VarTemplatePartialSpecializationDecl>(VD))
+      return;
 
     diag(VD->getLocation(),
          "variable %0 defined in a header file; "
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc-definitions-in-headers.hpp b/clang-tools-extra/test/clang-tidy/checkers/misc-definitions-in-headers.hpp
index c2a4a81ae3e1..f57cc2c256fe 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/misc-definitions-in-headers.hpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc-definitions-in-headers.hpp
@@ -193,6 +193,16 @@ const int f12() { return 0; }
 // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: full function template specialization 'f12<int>' defined in a header file;
 // CHECK-FIXES: inline const int f12() { return 0; }
 
+template <typename T1, typename T2>
+constexpr bool f13 = false;
+
+template <typename T>
+constexpr bool f13<T, int> = true; // OK: template partial specialization
+
+template <>
+constexpr bool f13<void, int> = false;
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: variable 'f13<void, int>' defined in a header file;
+
 int main() {}
 // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: function 'main' defined in a header file;
 // CHECK-FIXES: {{^}}int main() {