[gcc r14-10085] c++: Check if allocation functions are xobj members [PR114078]

[Nathaniel Shead <nshead@gcc.gnu.org>]

https://gcc.gnu.org/g:cf51fe706ea0219beb5bb85e81606d372ca9635e

commit r14-10085-gcf51fe706ea0219beb5bb85e81606d372ca9635e
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Sat Apr 20 15:08:02 2024 +1000

    c++: Check if allocation functions are xobj members [PR114078]
    
    A class allocation member function is implicitly 'static' by
    [class.free] p3, so cannot have an explicit object parameter.
    
            PR c++/114078
    
    gcc/cp/ChangeLog:
    
            * decl.cc (grokdeclarator): Check allocation functions for xobj
            parameters.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/cpp23/explicit-obj-ops-alloc.C: New test.
    
    Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>

Diff:
---
 gcc/cp/decl.cc                                      |  6 ++++++
 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-alloc.C | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 65ab64885ff..2af026d255d 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -13728,6 +13728,12 @@ grokdeclarator (const cp_declarator *declarator,
 			inform (DECL_SOURCE_LOCATION (xobj_parm),
 				"explicit object parameter declared here");
 		      }
+		    if (unqualified_id
+			&& identifier_p (unqualified_id)
+			&& IDENTIFIER_NEWDEL_OP_P (unqualified_id))
+		      error_at (DECL_SOURCE_LOCATION (xobj_parm),
+				"%qD cannot be an explicit object member "
+				"function", unqualified_id);
 		  }
 	      }
 	    tree pushed_scope = NULL_TREE;
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-alloc.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-alloc.C
new file mode 100644
index 00000000000..8a277db7ef5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-alloc.C
@@ -0,0 +1,11 @@
+// PR c++/114078
+// { dg-do compile { target c++23 } }
+
+using size_t = decltype(sizeof(0));
+
+struct S {
+  void* operator new(this size_t);  // { dg-error "explicit object" }
+  void* operator new[](this size_t);  // { dg-error "explicit object" }
+  void operator delete(this void*);  // { dg-error "explicit object" }
+  void operator delete[](this void*);  // { dg-error "explicit object" }
+};