[clang] [clang] Warn about deprecated volatile-qualified return types (PR #137899)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: None (halbi2)

<details>
<summary>Changes</summary>

Fixes #<!-- -->133380

---
Full diff: https://github.com/llvm/llvm-project/pull/137899.diff


3 Files Affected:

- (modified) clang/lib/Sema/SemaType.cpp (+5-5) 
- (modified) clang/test/CXX/expr/expr.const/p2-0x.cpp (+1-1) 
- (modified) clang/test/SemaCXX/deprecated.cpp (+7) 


``````````diff
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 6e7ee8b5506ff..31bdc97d014d6 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5056,13 +5056,13 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
           S.Diag(DeclType.Loc, diag::err_func_returning_qualified_void) << T;
         } else
           diagnoseRedundantReturnTypeQualifiers(S, T, D, chunkIndex);
-
-        // C++2a [dcl.fct]p12:
-        //   A volatile-qualified return type is deprecated
-        if (T.isVolatileQualified() && S.getLangOpts().CPlusPlus20)
-          S.Diag(DeclType.Loc, diag::warn_deprecated_volatile_return) << T;
       }
 
+      // C++2a [dcl.fct]p12:
+      //   A volatile-qualified return type is deprecated
+      if (T.isVolatileQualified() && S.getLangOpts().CPlusPlus20)
+        S.Diag(DeclType.Loc, diag::warn_deprecated_volatile_return) << T;
+
       // Objective-C ARC ownership qualifiers are ignored on the function
       // return type (by type canonicalization). Complain if this attribute
       // was written here.
diff --git a/clang/test/CXX/expr/expr.const/p2-0x.cpp b/clang/test/CXX/expr/expr.const/p2-0x.cpp
index df5ce108aca82..c6c3381be5523 100644
--- a/clang/test/CXX/expr/expr.const/p2-0x.cpp
+++ b/clang/test/CXX/expr/expr.const/p2-0x.cpp
@@ -356,7 +356,7 @@ namespace LValueToRValue {
   // - a non-volatile glvalue of literal type that refers to a non-volatile
   //   temporary object whose lifetime has not ended, initialized with a
   //   constant expression;
-  constexpr volatile S f() { return S(); }
+  constexpr volatile S f() { return S(); } // cxx20-warning {{volatile-qualified return type 'volatile S' is deprecated}}
   static_assert(f().i, ""); // expected-error {{constant expression}} expected-note {{read of volatile-qualified type}}
   static_assert(((volatile const S&&)(S)0).i, ""); // expected-error {{constant expression}} expected-note {{read of volatile-qualified type}}
 }
diff --git a/clang/test/SemaCXX/deprecated.cpp b/clang/test/SemaCXX/deprecated.cpp
index a24b40d8e622a..061fa8b54dff1 100644
--- a/clang/test/SemaCXX/deprecated.cpp
+++ b/clang/test/SemaCXX/deprecated.cpp
@@ -231,6 +231,13 @@ namespace DeprecatedVolatile {
     a = c = a;
     b += a;
   }
+
+  volatile struct amber jurassic();
+    // cxx20-warning at -1 {{volatile-qualified return type 'volatile struct amber' is deprecated}}
+  void trex(volatile short left_arm, volatile struct amber right_arm);
+    // cxx20-warning at -1 {{volatile-qualified parameter type 'volatile short' is deprecated}}
+    // cxx20-warning at -1 {{volatile-qualified parameter type 'volatile struct amber' is deprecated}}
+  void fly(volatile struct pterosaur* pteranodon);
 }
 
 namespace ArithConv {

``````````

</details>


https://github.com/llvm/llvm-project/pull/137899