From 6b50bfc8f25a4d78a17a9134c3e2e26c19bb7dff Mon Sep 17 00:00:00 2001
From: Nathan Ridge <zeratul976@hotmail.com>
Date: Fri, 27 Jan 2023 02:17:20 -0500
Subject: [PATCH] [clang] Store the template param list of an explicit variable
 template specialization

VarTemplateSpecializationDecl does not store a template param list,
so the "template<>" needs to be stored in the ExtInfo.

Differential Revision: https://reviews.llvm.org/D142692
---
 .../clangd/unittests/SemanticHighlightingTests.cpp         | 4 ++--
 clang/lib/Sema/SemaDecl.cpp                                | 7 ++++++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
index f5174979a8d6..cba318df3d2f 100644
--- a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
@@ -892,7 +892,7 @@ sizeof...($TemplateParameter[[Elements]]);
 
         template $Bracket[[<]]typename $TemplateParameter_def[[T]]$Bracket[[>]]
         $TemplateParameter[[T]] $Variable_def[[x]] = {};
-        template <>
+        template $Bracket[[<]]$Bracket[[>]]
         int $Variable_def[[x]]$Bracket[[<]]int$Bracket[[>]] = (int)sizeof($Class[[Base]]);
       )cpp",
       // operator calls in template
@@ -977,7 +977,7 @@ $Bracket[[>]]$Bracket[[>]] $LocalVariable_def[[s6]];
         }
         template $Bracket[[<]]typename $TemplateParameter_def[[T]]$Bracket[[>]] constexpr int $Variable_def_readonly[[V]] = 42;
         constexpr int $Variable_def_readonly[[Y]] = $Variable_readonly[[V]]$Bracket[[<]]char$Bracket[[>]];
-        template <>
+        template $Bracket[[<]]$Bracket[[>]]
         constexpr int $Variable_def_readonly[[V]]$Bracket[[<]]int$Bracket[[>]] = 5;
         template $Bracket[[<]]typename $TemplateParameter_def[[T]]$Bracket[[>]]
         constexpr int $Variable_def_readonly[[V]]$Bracket[[<]]$TemplateParameter[[T]]*$Bracket[[>]] = 6;
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index b9cea8bbf42c..0abf67f0d62d 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7674,7 +7674,12 @@ NamedDecl *Sema::ActOnVariableDeclarator(
 
     // If we have any template parameter lists that don't directly belong to
     // the variable (matching the scope specifier), store them.
-    unsigned VDTemplateParamLists = TemplateParams ? 1 : 0;
+    // An explicit variable template specialization does not own any template
+    // parameter lists.
+    bool IsExplicitSpecialization =
+        IsVariableTemplateSpecialization && !IsPartialSpecialization;
+    unsigned VDTemplateParamLists =
+        (TemplateParams && !IsExplicitSpecialization) ? 1 : 0;
     if (TemplateParamLists.size() > VDTemplateParamLists)
       NewVD->setTemplateParameterListsInfo(
           Context, TemplateParamLists.drop_back(VDTemplateParamLists));