[clang] [Clang]: enhance handling of [[deprecated]] attribute diagnostics for local variables (PR #113575)

[Oleksandr T. via cfe-commits]

https://github.com/a-tarasyuk updated https://github.com/llvm/llvm-project/pull/113575

>From 67a48d3861b44bd5c37fc9740ee2c54ddd1a8d1b Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.tarasiuk at outlook.com>
Date: Thu, 24 Oct 2024 17:21:39 +0300
Subject: [PATCH] [Clang] enhance handling of [[deprecated]] attribute
 diagnostics for local variables

---
 clang/docs/ReleaseNotes.rst         |  2 ++
 clang/lib/Sema/SemaAvailability.cpp |  6 ++++++
 clang/test/SemaCXX/deprecated.cpp   | 14 ++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 28bb83a1c9d60f..89c97d4b6631f2 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -424,6 +424,8 @@ Improvements to Clang's diagnostics
   name was a reserved name, which we improperly allowed to suppress the
   diagnostic.
 
+- Clang now diagnoses [[deprecated]] attribute usage on local variables (#GH90073).
+
 Improvements to Clang's time-trace
 ----------------------------------
 
diff --git a/clang/lib/Sema/SemaAvailability.cpp b/clang/lib/Sema/SemaAvailability.cpp
index 798cabaa31a476..d62b3eb1a480e7 100644
--- a/clang/lib/Sema/SemaAvailability.cpp
+++ b/clang/lib/Sema/SemaAvailability.cpp
@@ -182,6 +182,12 @@ static bool ShouldDiagnoseAvailabilityInContext(
       return false;
   }
 
+  if (K == AR_Deprecated) {
+    if (const auto *VD = dyn_cast<VarDecl>(OffendingDecl))
+      if (VD->isLocalVarDecl() && VD->isDeprecated())
+        return true;
+  }
+
   // Checks if we should emit the availability diagnostic in the context of C.
   auto CheckContext = [&](const Decl *C) {
     if (K == AR_NotYetIntroduced) {
diff --git a/clang/test/SemaCXX/deprecated.cpp b/clang/test/SemaCXX/deprecated.cpp
index a93331023f7e21..02fdf0bec5c088 100644
--- a/clang/test/SemaCXX/deprecated.cpp
+++ b/clang/test/SemaCXX/deprecated.cpp
@@ -260,5 +260,19 @@ namespace ArrayComp {
   bool b7 = arr1 == +f();
 }
 
+namespace GH90073 {
+[[deprecated]] int f() { // expected-note {{'f' has been explicitly marked deprecated here}}
+  [[deprecated]] int a;  // expected-note {{'a' has been explicitly marked deprecated here}} \
+                         // expected-note {{'a' has been explicitly marked deprecated here}}
+  a = 0;    // expected-warning {{'a' is deprecated}}
+  return a; // expected-warning {{'a' is deprecated}}
+}
+
+int main() {
+  f(); // expected-warning {{'f' is deprecated}}
+  return 0;
+}
+}
+
 # 1 "/usr/include/system-header.h" 1 3
 void system_header_function(void) throw();