https://github.com/a-tarasyuk created
https://github.com/llvm/llvm-project/pull/136328
Fixes #79893
---
This PR addresses the issue of _attributes_ being incorrectly allowed on
`extern template` declarations
```cpp
[[deprecated]] extern template struct S<int>;
```
>From 0729ae4d4a971905aefc8f1c1ec2ec81a0f149e9 Mon Sep 17 00:00:00 2001
From: Oleksandr Tarasiuk <oleksandr.taras...@outlook.com>
Date: Fri, 18 Apr 2025 20:09:56 +0300
Subject: [PATCH] [Clang] disallow use of attributes before extern template
declarations
---
clang/docs/ReleaseNotes.rst | 3 +++
clang/lib/Parse/Parser.cpp | 1 +
clang/test/Parser/extern-template-attributes.cpp | 6 ++++++
3 files changed, 10 insertions(+)
create mode 100644 clang/test/Parser/extern-template-attributes.cpp
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f5cd1fbeabcfe..cf0ec3e0bbf29 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -301,6 +301,9 @@ related warnings within the method body.
particularly relevant for AMDGPU targets, where they map to corresponding IR
metadata.
+- Clang now disallows the use of attributes applied before an
+ ``extern template`` declaration (#GH79893).
+
Improvements to Clang's diagnostics
-----------------------------------
diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index d528664bca352..25f8ed29d15fe 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -1049,6 +1049,7 @@ Parser::ParseExternalDeclaration(ParsedAttributes &Attrs,
case tok::kw_extern:
if (getLangOpts().CPlusPlus && NextToken().is(tok::kw_template)) {
+ ProhibitAttributes(Attrs);
// Extern templates
SourceLocation ExternLoc = ConsumeToken();
SourceLocation TemplateLoc = ConsumeToken();
diff --git a/clang/test/Parser/extern-template-attributes.cpp
b/clang/test/Parser/extern-template-attributes.cpp
new file mode 100644
index 0000000000000..0912ad69806db
--- /dev/null
+++ b/clang/test/Parser/extern-template-attributes.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -std=c++17 -verify %s
+
+template <class>
+struct S {};
+
+[[deprecated]] extern template struct S<int>; // expected-error {{an attribute
list cannot appear here}}
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