[clang] [clang] [SemaCXX] Disallow deducing "this" on operator `new` and `delete` (PR #82251)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Rajveer Singh Bharadwaj (Rajveer100)

<details>
<summary>Changes</summary>

Resolves Issue #<!-- -->82249

As described in the issue, any deallocation function for a `class X` is a static member (even if not explicitly declared static).

---
Full diff: https://github.com/llvm/llvm-project/pull/82251.diff


2 Files Affected:

- (modified) clang/lib/Sema/SemaDeclCXX.cpp (+3-1) 
- (modified) clang/test/SemaCXX/cxx2b-deducing-this.cpp (+4) 


``````````diff
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index ab8a967b06a456..7a7b544d82b640 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -11391,7 +11391,9 @@ void Sema::CheckExplicitObjectMemberFunction(Declarator &D,
         << ExplicitObjectParam->getSourceRange();
   }
 
-  if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_static) {
+  if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_static ||
+      (D.getContext() == clang::DeclaratorContext::Member &&
+       D.isStaticMember())) {
     Diag(ExplicitObjectParam->getBeginLoc(),
          diag::err_explicit_object_parameter_nonmember)
         << D.getSourceRange() << /*static=*/0 << IsLambda;
diff --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index aab35828096a8e..530f8bf6af1b6b 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -16,6 +16,10 @@ struct S {
     static void f(this auto); // expected-error{{an explicit object parameter cannot appear in a static function}}
     virtual void f(this S); // expected-error{{an explicit object parameter cannot appear in a virtual function}}
 
+    // new and delete are implicitly static
+    void *operator new(this unsigned long); // expected-error{{an explicit object parameter cannot appear in a static function}}
+    void operator delete(this void*); // expected-error{{an explicit object parameter cannot appear in a static function}}
+    
     void g(this auto) const; // expected-error{{explicit object member function cannot have 'const' qualifier}}
     void h(this auto) &; // expected-error{{explicit object member function cannot have '&' qualifier}}
     void i(this auto) &&; // expected-error{{explicit object member function cannot have '&&' qualifier}}

``````````

</details>


https://github.com/llvm/llvm-project/pull/82251