From e730dcba51503446cc362909fcab19361970b448 Mon Sep 17 00:00:00 2001
From: waffl3x <waffl3x@protonmail.com>
Date: Sat, 4 Nov 2023 05:35:10 -0600
Subject: [PATCH 1/2] c++: Initial support for C++23 P0847R7 (Deducing this)
 [PR102609]

This patch implements initial support for P0847R7 without diagnostics.  My goal
was to minimize changes to the existing code.  To achieve this I chose to treat
xobj member functions as static member functions, while opting into member
function handling when necessary.  This seemed to be the better choice since
most of the time they are more like static member functions.

This is achieved by inhibiting conversion of the declaration's type from
FUNCTION_TYPE to METHOD_TYPE.  Most if not everything seems to differentiate
between member functions and static member functions by inspecting the
FUNCTION_DECL's type, so forcing this is sufficient.  An xobj member function
is any member function that is declared with an xobj parameter as it's first
parameter.  This information is passed through the declarator's parameter list,
stored in the purpose of the parameter's tree_list node.  Normally this is used
to store default arguments, but as default arguments are not allowed for xobj
parameters it is fine for us to hijack it.  By utilizing this we can pass this
information from cp_parser_parameter_declaration over to grokdeclarator without
adding anything new to the tree structs.

We still need to differentiate this new function variety from static member
functions and regular functions, and since this information needs to stick to
the declaration we should select a more concrete place to store it.  Unlike the
previous hack for parameters, we instead add a flag to lang_decl_fn,  the only
modification this patch makes to any tree data-structures.  We could probably
try to stick the information in the decl's parameters somewhere, but I think a
proper flag is justified.  The new flag can be set and cleared through
DECL_FUNCTION_XOBJ_FLAG, it is invalid to use this with anything other than
FUNCTION_DECL nodes.  For inspecting the value of this flag
DECL_XOBJ_MEMBER_FUNC_P should be used, this macro is safe to use with any node
type and will harmlessly evaluate to false for invalid node types.

It needs to be noted that we can not add checking for xobj member functions to
DECL_NONSTATIC_MEMBER_FUNCTION_P as it is used in cp-objcp-common.cc.  While it
most likely would be fine, it's possible it could have unintended effects.  In
light of this, we will most likely need to do some refactoring, possibly
renaming and replacing it.  In contrast, DECL_FUNCTION_MEMBER_P is not used
outside of C++ code, so we can add checking for xobj member functions to it
without any concerns.

There are a few known issues still present in this patch.  Most importantly,
the implicit object argument fails to convert when passed to by-value xobj
parameters.  This occurs both for xobj parameters that match the argument type
and xobj parameters that are unrelated to the object type, but have valid
conversions available.  This behavior can be observed in the
explicit-obj-by-value[1-3].C tests.  The implicit object argument appears to be
simply reinterpreted instead of any conversion applied.  This is elaborated on
in the test cases.  Despite this, calls where there is no valid conversion
available are correctly rejected, which I find surprising.  The
explicit-obj-by-value4.C testcase demonstrates this odd but correct behavior.
Other than this, lambdas are not yet supported, and there is some outstanding
odd behavior where invalid calls to operators are improperly accepted.  The
test for this utilizes requires expressions to operate though so it's possible
that the problems originate from there, but I have a hunch they aren't
responsible.  See explicit-obj-ops-requires-mem.C and
explicit-obj-ops-requires-non-mem.C for those tests.

One of the more invasive changes I chose to make is in
build_min_non_dep_op_overload, I flipped the if branches because the conditions
make significantly more sense when METHOD_TYPE is tested for first.  It did not
appear that the previous ordering was for any particular purpose so I felt it
was better to flip it than make the conditions significantly more confusing.  I
did want to note this change in particular just in case.

	PR c++/102609

gcc/cp/ChangeLog:

	PR c++/102609
	Initial support for C++23 P0847R7 - Deducing this.
	* call.cc (add_candidates): Check if fn is an xobj member function.
	(build_over_call): Ditto.
	* cp-tree.h (struct lang_decl_fn::xobj_func): New data member.
	(DECL_FUNCTION_XOBJ_FLAG): Define.
	(DECL_XOBJ_MEMBER_FUNC_P): Define.
	(DECL_FUNCTION_MEMBER_P): Add check for xobj member functions.
	(enum cp_decl_spec): Add ds_this.
	* decl.cc (grokfndecl): New param XOBJ_FUNC_P, for xobj member
	functions set DECL_FUNCTION_XOBJ_FLAG and don't set
	DECL_STATIC_FUNCTION_P.
	(grokdeclarator): Check for xobj param, clear it's purpose and set
	is_xobj_member_function if it is present.  When flag set, don't change
        type to METHOD_TYPE, keep it as FUNCTION_TYPE.
	Adjust call to grokfndecl, pass is_xobj_member_function.
	(grok_op_properties): Treat xobj member functions as iobj member
	functions.
	* parser.cc (cp_parser_decl_specifier_seq): Handle "this" specifier.
	(cp_parser_parameter_declaration): When "this" decl spec present, set
	default_argument to this_identifier.
	(set_and_check_decl_spec_loc) <decl_spec_names>: Add "this".
	* tree.cc (build_min_non_dep_op_overload): Flip if branches, treat
	xobj member functions as iobj member functions.
	* typeck.cc (cp_build_addr_expr_1): Handle xobj member functions
	without overloads.

gcc/testsuite/ChangeLog:

	PR c++/102609
	Initial support for C++23 P0847R7 - Deducing this.
	* g++.dg/cpp23/explicit-obj-basic1.C: New test.
	* g++.dg/cpp23/explicit-obj-basic2.C: New test.
	* g++.dg/cpp23/explicit-obj-by-value1.C: New test.
	* g++.dg/cpp23/explicit-obj-by-value2.C: New test.
	* g++.dg/cpp23/explicit-obj-by-value3.C: New test.
	* g++.dg/cpp23/explicit-obj-by-value4.C: New test.
	* g++.dg/cpp23/explicit-obj-lambda1.C: New test.
	* g++.dg/cpp23/explicit-obj-ops-mem-arrow.C: New test.
	* g++.dg/cpp23/explicit-obj-ops-mem-assignment.C: New test.
	* g++.dg/cpp23/explicit-obj-ops-mem-call.C: New test.
	* g++.dg/cpp23/explicit-obj-ops-mem-subscript.C: New test.
	* g++.dg/cpp23/explicit-obj-ops-non-mem-dep.C: New test.
	* g++.dg/cpp23/explicit-obj-ops-non-mem-non-dep.C: New test.
	* g++.dg/cpp23/explicit-obj-ops-non-mem.h: New test.
	* g++.dg/cpp23/explicit-obj-ops-requires-mem.C: New test.
	* g++.dg/cpp23/explicit-obj-ops-requires-non-mem.C: New test.

Signed-off-by: waffl3x <waffl3x@protonmail.com>
---
 gcc/cp/call.cc                                |   9 +-
 gcc/cp/cp-tree.h                              |  25 +-
 gcc/cp/decl.cc                                |  44 +++-
 gcc/cp/parser.cc                              |  20 +-
 gcc/cp/tree.cc                                |  26 +-
 gcc/cp/typeck.cc                              |   6 +
 .../g++.dg/cpp23/explicit-obj-basic1.C        | 113 +++++++++
 .../g++.dg/cpp23/explicit-obj-basic2.C        |  27 +++
 .../g++.dg/cpp23/explicit-obj-by-value1.C     |  49 ++++
 .../g++.dg/cpp23/explicit-obj-by-value2.C     |  59 +++++
 .../g++.dg/cpp23/explicit-obj-by-value3.C     |  42 ++++
 .../g++.dg/cpp23/explicit-obj-by-value4.C     |  19 ++
 .../g++.dg/cpp23/explicit-obj-lambda1.C       |  11 +
 .../g++.dg/cpp23/explicit-obj-ops-mem-arrow.C |  27 +++
 .../cpp23/explicit-obj-ops-mem-assignment.C   |  26 ++
 .../g++.dg/cpp23/explicit-obj-ops-mem-call.C  |  39 +++
 .../cpp23/explicit-obj-ops-mem-subscript.C    |  39 +++
 .../cpp23/explicit-obj-ops-non-mem-dep.C      |  57 +++++
 .../cpp23/explicit-obj-ops-non-mem-non-dep.C  |  56 +++++
 .../g++.dg/cpp23/explicit-obj-ops-non-mem.h   | 202 +++++++++++++++
 .../cpp23/explicit-obj-ops-requires-mem.C     | 172 +++++++++++++
 .../cpp23/explicit-obj-ops-requires-non-mem.C | 229 ++++++++++++++++++
 22 files changed, 1266 insertions(+), 31 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-basic1.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-basic2.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value1.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value2.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value3.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value4.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda1.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-arrow.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-assignment.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-call.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-subscript.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem-dep.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem-non-dep.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem.h
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-requires-mem.C
 create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-requires-non-mem.C

diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index 2eb54b5b6ed..c7ca32d1d34 100644
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -6526,8 +6526,10 @@ add_candidates (tree fns, tree first_arg, const vec<tree, va_gc> *args,
 
       tree fn_first_arg = NULL_TREE;
       const vec<tree, va_gc> *fn_args = args;
-
-      if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn))
+      /* We can't add xobj member functions to DECL_NONSTATIC_MEMBER_FUNCTION_P,
+	 for now just check for them specifically.  */
+      if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)
+	  || DECL_XOBJ_MEMBER_FUNC_P (fn))
 	{
 	  /* Figure out where the object arg comes from.  If this
 	     function is a non-static member and we didn't get an
@@ -9949,7 +9951,8 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
 	}
     }
   /* Bypass access control for 'this' parameter.  */
-  else if (TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
+  else if (TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE
+	   || DECL_XOBJ_MEMBER_FUNC_P (fn))
     {
       tree arg = build_this (first_arg != NULL_TREE
 			     ? first_arg
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 98b29e9cf81..901fb1f4616 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -2938,8 +2938,9 @@ struct GTY(()) lang_decl_fn {
   unsigned maybe_deleted : 1;
   unsigned coroutine_p : 1;
   unsigned implicit_constexpr : 1;
+  unsigned xobj_func : 1;
 
-  unsigned spare : 9;
+  unsigned spare : 8;
 
   /* 32-bits padding on 64-bit host.  */
 
@@ -3338,14 +3339,25 @@ struct GTY(()) lang_decl {
   (LANG_DECL_FN_CHECK (NODE)->static_function)
 
 /* Nonzero for FUNCTION_DECL means that this decl is a non-static
-   member function.  */
+   member function, UNLESS it is an xobj member function.
+   This inconsistency will be fixed in the future.  */
 #define DECL_NONSTATIC_MEMBER_FUNCTION_P(NODE) \
   (TREE_CODE (TREE_TYPE (NODE)) == METHOD_TYPE)
 
+/* Simple member access, only valid for FUNCTION_DECL nodes.  */
+#define DECL_FUNCTION_XOBJ_FLAG(NODE)	\
+  (LANG_DECL_FN_CHECK (NODE)->xobj_func)
+/* Nonzero if NODE is a FUNCTION_DECL that is an xobj member function,
+   safely evaluates to false for all non FUNCTION_DECL nodes.  */
+#define DECL_XOBJ_MEMBER_FUNC_P(NODE)			\
+  (TREE_CODE (STRIP_TEMPLATE (NODE)) == FUNCTION_DECL	\
+   && DECL_FUNCTION_XOBJ_FLAG (NODE) == 1)
+
 /* Nonzero for FUNCTION_DECL means that this decl is a member function
    (static or non-static).  */
 #define DECL_FUNCTION_MEMBER_P(NODE) \
-  (DECL_NONSTATIC_MEMBER_FUNCTION_P (NODE) || DECL_STATIC_FUNCTION_P (NODE))
+  (DECL_NONSTATIC_MEMBER_FUNCTION_P (NODE) || DECL_STATIC_FUNCTION_P (NODE) \
+  || DECL_XOBJ_MEMBER_FUNC_P (NODE))
 
 /* Nonzero for FUNCTION_DECL means that this member function
    has `this' as const X *const.  */
@@ -6264,11 +6276,13 @@ enum cp_storage_class {
 
 /* An individual decl-specifier.  This is used to index the array of
    locations for the declspecs in struct cp_decl_specifier_seq
-   below.  */
+   below.
+   A subset of these enums also corresponds to elements of
+   cp_parser_set_decl_spec_type:decl_spec_names in parser.cc.  */
 
 enum cp_decl_spec {
   ds_first,
-  ds_signed = ds_first,
+  ds_signed = ds_first, /* Index of first element of decl_spec_names.  */
   ds_unsigned,
   ds_short,
   ds_long,
@@ -6285,6 +6299,7 @@ enum cp_decl_spec {
   ds_complex,
   ds_constinit,
   ds_consteval,
+  ds_this, /* Index of last element of decl_spec_names.  */
   ds_thread,
   ds_type_spec,
   ds_redefined_builtin_type_spec,
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 16af59de696..c02d78b8102 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -10318,6 +10318,7 @@ grokfndecl (tree ctype,
 	    int publicp,
 	    int inlinep,
 	    bool deletedp,
+	    bool xobj_func_p,
 	    special_function_kind sfk,
 	    bool funcdef_flag,
 	    bool late_return_type_p,
@@ -10327,7 +10328,6 @@ grokfndecl (tree ctype,
 	    location_t location)
 {
   tree decl;
-  int staticp = ctype && TREE_CODE (type) == FUNCTION_TYPE;
   tree t;
 
   if (location == UNKNOWN_LOCATION)
@@ -10525,12 +10525,9 @@ grokfndecl (tree ctype,
 		  (IDENTIFIER_POINTER (declarator))))))
     SET_DECL_LANGUAGE (decl, lang_c);
 
-  /* Should probably propagate const out from type to decl I bet (mrs).  */
-  if (staticp)
-    {
-      DECL_STATIC_FUNCTION_P (decl) = 1;
-      DECL_CONTEXT (decl) = ctype;
-    }
+  DECL_STATIC_FUNCTION_P (decl)
+    = !xobj_func_p && ctype && TREE_CODE (type) == FUNCTION_TYPE;
+  DECL_FUNCTION_XOBJ_FLAG (decl) = xobj_func_p;
 
   if (deletedp)
     DECL_DELETED_FN (decl) = 1;
@@ -12998,6 +12995,8 @@ grokdeclarator (const cp_declarator *declarator,
   if (attrlist)
     diagnose_misapplied_contracts (*attrlist);
 
+  /* Skip over build_memfn_type when a FUNCTION_DECL is an xobj memfn.  */
+  bool is_xobj_member_function = false;
   /* Determine the type of the entity declared by recurring on the
      declarator.  */
   for (; declarator; declarator = declarator->declarator)
@@ -13113,6 +13112,25 @@ grokdeclarator (const cp_declarator *declarator,
 	    if (raises == error_mark_node)
 	      raises = NULL_TREE;
 
+	    auto find_xobj_parm = [](tree parm_list)
+	      {
+		/* There is no need to iterate over the list,
+		   only the first parm can be a valid xobj parm.  */
+		if (!parm_list || parm_list == void_list_node)
+		  return false;
+		if (TREE_PURPOSE (parm_list) != this_identifier)
+		  return false;
+		/* If we make it here, we are looking at an xobj parm.
+
+		   Non-null 'purpose' usually means the parm has a default
+		   argument, we don't want to violate this assumption.  */
+		TREE_PURPOSE (parm_list) = NULL_TREE;
+		return true;
+	      };
+
+	    is_xobj_member_function
+	      = find_xobj_parm (declarator->u.function.parameters);
+
 	    if (reqs)
 	      error_at (location_of (reqs), "requires-clause on return type");
 	    reqs = declarator->u.function.requires_clause;
@@ -14177,6 +14195,8 @@ grokdeclarator (const cp_declarator *declarator,
     }
 
   if (ctype && TREE_CODE (type) == FUNCTION_TYPE && staticp < 2
+      /* Don't convert xobj member functions to METHOD_TYPE.  */
+      && !is_xobj_member_function
       && !(unqualified_id
 	   && identifier_p (unqualified_id)
 	   && IDENTIFIER_NEWDEL_OP_P (unqualified_id)))
@@ -14398,7 +14418,8 @@ grokdeclarator (const cp_declarator *declarator,
 			       friendp ? -1 : 0, friendp, publicp,
 			       inlinep | (2 * constexpr_p) | (4 * concept_p)
 				       | (8 * consteval_p),
-			       initialized == SD_DELETED, sfk,
+			       initialized == SD_DELETED,
+			       is_xobj_member_function, sfk,
 			       funcdef_flag, late_return_type_p,
 			       template_count, in_namespace,
 			       attrlist, id_loc);
@@ -14733,8 +14754,8 @@ grokdeclarator (const cp_declarator *declarator,
 			   inlinep | (2 * constexpr_p) | (4 * concept_p)
 				   | (8 * consteval_p),
 			   initialized == SD_DELETED,
-                           sfk,
-                           funcdef_flag,
+			   is_xobj_member_function, sfk,
+			   funcdef_flag,
 			   late_return_type_p,
 			   template_count, in_namespace, attrlist,
 			   id_loc);
@@ -15628,7 +15649,8 @@ grok_op_properties (tree decl, bool complain)
   /* An operator function must either be a non-static member function
      or have at least one parameter of a class, a reference to a class,
      an enumeration, or a reference to an enumeration.  13.4.0.6 */
-  if (! methodp || DECL_STATIC_FUNCTION_P (decl))
+  if ((!methodp && !DECL_XOBJ_MEMBER_FUNC_P (decl))
+      || DECL_STATIC_FUNCTION_P (decl))
     {
       if (operator_code == TYPE_EXPR
 	  || operator_code == COMPONENT_REF
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 20e18365906..4fbcc52c222 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -16091,6 +16091,16 @@ cp_parser_decl_specifier_seq (cp_parser* parser,
 	    decl_specs->locations[ds_attribute] = token->location;
 	  continue;
 	}
+      /* Special case for "this" specifier, indicating a parm is an xobj parm.
+	 The "this" specifier must be the first specifier in the declaration,
+	 after any attributes.  */
+      if (token->keyword == RID_THIS)
+	{
+	  cp_lexer_consume_token (parser->lexer);
+	  set_and_check_decl_spec_loc (decl_specs, ds_this, token);
+	  continue;
+	}
+
       /* Assume we will find a decl-specifier keyword.  */
       found_decl_spec = true;
       /* If the next token is an appropriate keyword, we can simply
@@ -25495,6 +25505,13 @@ cp_parser_parameter_declaration (cp_parser *parser,
   if (default_argument)
     STRIP_ANY_LOCATION_WRAPPER (default_argument);
 
+  if (decl_spec_seq_has_spec_p (&decl_specifiers, ds_this))
+    {
+      /* Xobj parameters can not have default arguments, thus
+	 we can reuse the default argument field to flag the param as such.  */
+      default_argument = this_identifier;
+    }
+
   /* Generate a location for the parameter, ranging from the start of the
      initial token to the end of the final token (using input_location for
      the latter, set up by cp_lexer_set_source_position_from_token when
@@ -33873,7 +33890,8 @@ set_and_check_decl_spec_loc (cp_decl_specifier_seq *decl_specs,
 	    "constexpr",
 	    "__complex",
 	    "constinit",
-	    "consteval"
+	    "consteval",
+	    "this"
 	  };
 	  gcc_rich_location richloc (location);
 	  richloc.add_fixit_remove ();
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index 417c92ba76f..ab5fe79146c 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -3660,6 +3660,7 @@ build_min_non_dep_op_overload (enum tree_code op,
 
   expected_nargs = cp_tree_code_length (op);
   if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE
+      || DECL_XOBJ_MEMBER_FUNC_P (overload)
       /* For ARRAY_REF, operator[] is either a non-static member or newly
 	 static member, never out of class and for the static member case
 	 if user uses single index the operator[] needs to have a single
@@ -3677,24 +3678,26 @@ build_min_non_dep_op_overload (enum tree_code op,
   releasing_vec args;
   va_start (p, overload);
 
-  if (TREE_CODE (TREE_TYPE (overload)) == FUNCTION_TYPE)
+  if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE
+	   || DECL_XOBJ_MEMBER_FUNC_P (overload))
     {
-      fn = overload;
-      if (op == ARRAY_REF)
-	obj = va_arg (p, tree);
+      tree object = va_arg (p, tree);
+      tree binfo = TYPE_BINFO (TREE_TYPE (object));
+      tree method = build_baselink (binfo, binfo, overload, NULL_TREE);
+      fn = build_min (COMPONENT_REF, TREE_TYPE (overload),
+		      object, method, NULL_TREE);
       for (int i = 0; i < nargs; i++)
 	{
 	  tree arg = va_arg (p, tree);
 	  vec_safe_push (args, arg);
 	}
     }
-  else if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE)
+  else if (TREE_CODE (TREE_TYPE (overload)) == FUNCTION_TYPE)
     {
-      tree object = va_arg (p, tree);
-      tree binfo = TYPE_BINFO (TREE_TYPE (object));
-      tree method = build_baselink (binfo, binfo, overload, NULL_TREE);
-      fn = build_min (COMPONENT_REF, TREE_TYPE (overload),
-		      object, method, NULL_TREE);
+      gcc_assert (!DECL_XOBJ_MEMBER_FUNC_P (overload));
+      fn = overload;
+      if (op == ARRAY_REF)
+	obj = va_arg (p, tree);
       for (int i = 0; i < nargs; i++)
 	{
 	  tree arg = va_arg (p, tree);
@@ -3729,7 +3732,8 @@ build_min_non_dep_op_overload (tree non_dep, tree overload, tree object,
 
   unsigned int nargs = call_expr_nargs (non_dep);
   tree fn = overload;
-  if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE)
+  if (TREE_CODE (TREE_TYPE (overload)) == METHOD_TYPE
+      || DECL_XOBJ_MEMBER_FUNC_P (overload))
     {
       tree binfo = TYPE_BINFO (TREE_TYPE (object));
       tree method = build_baselink (binfo, binfo, overload, NULL_TREE);
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 49afbd8fb5e..00b999cec19 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -7164,6 +7164,12 @@ cp_build_addr_expr_1 (tree arg, bool strict_lvalue, tsubst_flags_t complain)
 	    && !mark_used (t, complain) && !(complain & tf_error))
 	  return error_mark_node;
 
+	/* Exception for non-overloaded explicit object member function.
+	   I am pretty sure this is not perfect, I think we aren't
+	   handling some constexpr stuff, but I am leaving it for now. */
+	if (TREE_CODE (TREE_TYPE (t)) == FUNCTION_TYPE)
+	  return build_address (t);
+
 	type = build_ptrmem_type (context_for_name_lookup (t),
 				  TREE_TYPE (t));
 	t = make_ptrmem_cst (type, t);
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-basic1.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-basic1.C
new file mode 100644
index 00000000000..1e44c9123b7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-basic1.C
@@ -0,0 +1,113 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// basic use cases and calling
+
+// non-trailing return
+// definitions
+struct S0 {
+  void f0(this S0) {}
+  void f1(this S0&) {}
+  void f2(this S0&&) {}
+  void f3(this S0 const&) {}
+  void f4(this S0 const&&) {}
+  template<typename Self>
+  void d0(this Self&&) {}
+  void d1(this auto&&) {}
+};
+// declarations
+struct S1 {
+  void f0(this S1);
+  void f1(this S1&);
+  void f2(this S1&&);
+  void f3(this S1 const&);
+  void f4(this S1 const&&);
+  template<typename Self>
+  void d0(this Self&&);
+  void d1(this auto&&);
+};
+// out of line definitions
+void S1::f0(this S1) {}
+void S1::f1(this S1&) {}
+void S1::f2(this S1&&) {}
+void S1::f3(this S1 const&) {}
+void S1::f4(this S1 const&&) {}
+template<typename Self>
+void S1::d0(this Self&&) {}
+void S1::d1(this auto&&) {}
+
+// trailing return
+// definitions
+struct S2 {
+  auto f0(this S2) -> void {}
+  auto f1(this S2&) -> void {}
+  auto f2(this S2&&) -> void {}
+  auto f3(this S2 const&) -> void {}
+  auto f4(this S2 const&&) -> void {}
+  template<typename Self>
+  auto d0(this Self&&) -> void {}
+
+  auto d1(this auto&&) -> void {}
+};
+// declarations
+struct S3 {
+  auto f0(this S3) -> void;
+  auto f1(this S3&) -> void;
+  auto f2(this S3&&) -> void;
+  auto f3(this S3 const&) -> void;
+  auto f4(this S3 const&&) -> void;
+  template<typename Self>
+  auto d0(this Self&&) -> void;
+  auto d1(this auto&&) -> void;
+};
+// out of line definitions
+auto S3::f0(this S3) -> void {}
+auto S3::f1(this S3&) -> void {}
+auto S3::f2(this S3&&) -> void {}
+auto S3::f3(this S3 const&) -> void {}
+auto S3::f4(this S3 const&&) -> void {}
+template<typename Self>
+auto S3::d0(this Self&&) -> void {}
+auto S3::d1(this auto&&) -> void {}
+
+template<typename T>
+void call_with_qualification()
+{
+  T obj{};
+  // by value should take any qualification (f0)
+  T{}.f0();
+  obj.f0();
+  static_cast<T&&>(obj).f0(); 
+  static_cast<T const&>(obj).f0();
+  static_cast<T const&&>(obj).f0();
+  // specific qualification (f1 - f4)
+  T{}.f2();
+  T{}.f3();
+  T{}.f4();
+  obj.f1();
+  obj.f3();
+  static_cast<T&&>(obj).f2();
+  static_cast<T&&>(obj).f3();
+  static_cast<T&&>(obj).f4();
+  static_cast<T const&>(obj).f3();
+  static_cast<T const&&>(obj).f4();
+  // deduced should (obviously) take any qualification (d0, d1)
+  T{}.d0();
+  obj.d0();
+  static_cast<T&&>(obj).d0();
+  static_cast<T const&>(obj).d0();
+  static_cast<T const&&>(obj).d0();
+  T{}.d1();
+  obj.d1();
+  static_cast<T&&>(obj).d1();
+  static_cast<T const&>(obj).d1();
+  static_cast<T const&&>(obj).d1();
+}
+
+void perform_calls()
+{
+  call_with_qualification<S0>();
+  call_with_qualification<S1>();
+  call_with_qualification<S2>();
+  call_with_qualification<S3>();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-basic2.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-basic2.C
new file mode 100644
index 00000000000..2c2b69ad362
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-basic2.C
@@ -0,0 +1,27 @@
+// P0847R7
+// { dg-do run { target c++23 } }
+
+// explicit object member function pointer type deduction,
+// conversion to function pointer,
+// and calling through pointer to function
+
+struct S {
+  int _n;
+  int f(this S& self) { return self._n; }
+};
+
+using f_type = int(*)(S&);
+
+static_assert (__is_same (f_type, decltype (&S::f)));
+
+int main()
+{
+  auto fp0 = &S::f;
+  f_type fp1 = &S::f;
+  static_assert (__is_same (decltype (fp0), decltype (fp1)));
+  S s{42};
+  if (fp0 (s) != 42)
+    __builtin_abort ();
+  if (fp1 (s) != 42)
+    __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value1.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value1.C
new file mode 100644
index 00000000000..e85c9ab03b0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value1.C
@@ -0,0 +1,49 @@
+// P0847R7
+// { dg-do run { target c++23 } }
+
+// conversion of the implicit object argument to an xobj parameter
+// when calling by value xobj member functions
+
+// The initial implementation of xobj member functions incorrectly did not
+// convert the implicit object argument when binding to the xobj
+// parameter. In spite of this, it did correctly check to see if such a
+// conversion would be valid, thus no diagnostic would be emitted when a
+// conversion was valid, but instead of applying the conversion, the
+// argument would silently be reinterpreted as the type of the parameter. 
+
+// This is why we use uintptr_t for the value in S and compare the result
+// of f to &s, we want to test for simple reinterpretation of the
+// argument. To accurately test for this we make sure to use an object
+// that has a different address than the value of our magic number. It's
+// an impossibly improbable edge case but it's trivial to work around. We
+// still compare against both the address of s and the magic number so we
+// can additionally test for bugged conversions, while also
+// differentiating that case from reinterpretation of the argument.
+
+// { dg-xfail-run-if "by value explicit object parameter is not supported yet" { *-*-* } }
+
+using uintptr_t = __UINTPTR_TYPE__;
+inline constexpr uintptr_t magic = 42;
+
+struct S {
+    uintptr_t _v;
+    uintptr_t f(this S self) {
+        return self._v;
+    }
+};
+
+int main() 
+{
+  S s0{magic};
+  S s1{magic};
+  // prevent (absurdly improbable) bogus failures
+  S& s = magic != (uintptr_t)(&s0) ? s0 : s1;
+
+  uintptr_t const ret = s.f();
+  // check for reinterpretation of the object argument
+  if (ret == (uintptr_t)(&s))
+    __builtin_abort ();
+  // check for a bugged conversion
+  if (ret != magic)
+    __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value2.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value2.C
new file mode 100644
index 00000000000..051439bb1df
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value2.C
@@ -0,0 +1,59 @@
+// P0847R7
+// { dg-do run { target c++23 } }
+
+// conversion of the implicit object argument to an xobj parameter
+// using a user defined conversion or converting constructor
+// when calling by value xobj member functions
+
+// see explicit-obj-by-value1.C for details on this test
+
+// { dg-xfail-run-if "user defined conversions from an implicit object argument to an explicit object parameter are not supported yet" { *-*-* } }
+
+using uintptr_t = __UINTPTR_TYPE__;
+inline constexpr uintptr_t magic = 42;
+
+struct S;
+
+struct FromS {
+  uintptr_t _v;
+  FromS(S);
+};
+
+struct S {
+  operator uintptr_t() const {
+    return magic;
+  }
+  uintptr_t f(this uintptr_t n) {
+    return n;
+  }
+  uintptr_t g(this FromS from_s) {
+    return from_s._v;
+  }
+};
+
+FromS::FromS(S) : _v(magic) {}
+
+
+int main() 
+{
+  S s0{};
+  S s1{};
+  // prevent (absurdly improbable) bogus failures
+  S& s = magic != (uintptr_t)(&s0) ? s0 : s1;
+
+  uintptr_t const ret0 = s.f();
+  // check for reinterpretation of the object argument
+  if (ret0 == (uintptr_t)(&s))
+    __builtin_abort ();
+  // check for a bugged conversion
+  if (ret0 != magic)
+    __builtin_abort ();
+
+  uintptr_t const ret1 = s.g();
+  // check for reinterpretation of the object argument
+  if (ret1 == (uintptr_t)(&s))
+    __builtin_abort ();
+  // check for a bugged conversion
+  if (ret1 != magic)
+    __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value3.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value3.C
new file mode 100644
index 00000000000..30e556bd6cb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value3.C
@@ -0,0 +1,42 @@
+// P0847R7
+// { dg-do run { target c++23 } }
+
+// correct constructor selection when initializing a by value xobj parameter
+
+// see explicit-obj-by-value1.C for details on this test
+
+// { dg-xfail-run-if "by value explicit object parameter is not supported yet" { *-*-* } }
+
+using uintptr_t = __UINTPTR_TYPE__;
+inline constexpr uintptr_t magic = 42;
+inline constexpr uintptr_t copy_magic = 5;
+inline constexpr uintptr_t move_magic = 10;
+
+struct S {
+  uintptr_t _v;
+  explicit S(uintptr_t v) : _v(v) {}
+  S(S const& other) : _v(other._v + copy_magic) {}
+  S(S&& other) : _v(other._v + move_magic) {}
+  uintptr_t f(this S self) {
+    return self._v;
+  }
+};
+
+int main() 
+{
+  S s0{magic};
+  S s1{magic};
+  // prevent (absurdly improbable (^2)) bogus results
+  // it's virtually impossible for both to have a bogus result,
+  // but we can guarantee correct results from both easily, so why not?
+  S& s_copy_from = magic + copy_magic != (uintptr_t)(&s0) ? s0 : s1;
+  S& s_move_from = magic + move_magic != (uintptr_t)(&s0) ? s0 : s1;
+  uintptr_t const copy_ret = static_cast<S const&>(s_copy_from).f();
+  uintptr_t const move_ret = static_cast<S&&>(s_move_from).f();
+  // we test specifically for reinterpretation in other
+  // by value tests, it's unnecessary to do it again here
+  if (copy_ret != magic + copy_magic)
+    __builtin_abort ();
+  if (move_ret != magic + move_magic)
+    __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value4.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value4.C
new file mode 100644
index 00000000000..d3c5e393e7b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-by-value4.C
@@ -0,0 +1,19 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// diagnosis of ill-formed calls to by-value xobj member functions
+// due to an absence of valid conversion functions
+
+struct NotFromS {};
+
+struct S {
+  void f(this int) {}
+  void g(this NotFromS) {}
+};
+
+void test()
+{
+  S s{};
+  s.f(); // { dg-error {cannot convert 'S' to 'int'} }
+  s.g(); // { dg-error {cannot convert 'S' to 'NotFromS'} }
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda1.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda1.C
new file mode 100644
index 00000000000..913fb3ca5ce
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda1.C
@@ -0,0 +1,11 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// lambda declaration with xobj parameter
+
+// { dg-excess-errors "explicit object parameter with lambdas not implemented yet" { xfail *-*-* } }
+
+void test()
+{
+  (void)[](this auto&& self){};
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-arrow.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-arrow.C
new file mode 100644
index 00000000000..c5b2c805a2f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-arrow.C
@@ -0,0 +1,27 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// uses of member only operators (arrow)
+
+struct S {
+  int _v;
+  S* operator->(this S& self) { return &self; }
+};
+
+void non_dep()
+{
+  S s{};
+  (void)s->_v;
+}
+
+template<typename = void>
+void dependent()
+{
+  S s{};
+  (void)s->_v;
+}
+
+void call()
+{
+  dependent();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-assignment.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-assignment.C
new file mode 100644
index 00000000000..829c7137abc
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-assignment.C
@@ -0,0 +1,26 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// uses of member only operators (assignment)
+
+struct S {
+  void operator=(this S&, int) {}
+};
+
+void non_dep()
+{
+  S s{};
+  s = 0;
+}
+
+template<typename = void>
+void dependent()
+{
+  S s{};
+  s = 0;
+}
+
+void call()
+{
+  dependent();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-call.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-call.C
new file mode 100644
index 00000000000..1dfe764de83
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-call.C
@@ -0,0 +1,39 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// uses of member only operators (call op)
+
+// execution paths for subscript with 1 argument and 0 and 2+ arguments are different
+// just to be safe, also test 0 and 2 argument cases here too
+
+struct S {
+  void operator()(this S&) {}
+  void operator()(this S&, int) {}
+  void operator()(this S&, int, int) {}
+  template<typename... Args>
+  void operator()(this S&, Args... args) {}
+};
+
+void non_dep()
+{
+  S s{};
+  s();
+  s(0);
+  s(0, 0);
+  s(0, 0, 0);
+}
+
+template<typename = void>
+void dependent()
+{
+  S s{};
+  s();
+  s(0);
+  s(0, 0);
+  s(0, 0, 0);
+}
+
+void call()
+{
+  dependent();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-subscript.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-subscript.C
new file mode 100644
index 00000000000..cee5f6e135c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-mem-subscript.C
@@ -0,0 +1,39 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// uses of member only operators (subscript)
+
+// execution paths for subscript with 1 argument and 0 and 2+ arguments are different
+// therefore we should additionally test the 0 and 2 argument cases as well
+
+struct S {
+  void operator[](this S&) {}
+  void operator[](this S&, int) {}
+  void operator[](this S&, int, int) {}
+  template<typename... Args>
+  void operator[](this S&, Args... args) {}
+};
+
+void non_dep()
+{
+  S s{};
+  s[];
+  s[0];
+  s[0, 0];
+  s[0, 0, 0];
+}
+
+template<typename = void>
+void dependent()
+{
+  S s{};
+  s[];
+  s[0];
+  s[0, 0];
+  s[0, 0, 0];
+}
+
+void call()
+{
+  dependent();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem-dep.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem-dep.C
new file mode 100644
index 00000000000..3c9f93fbcc2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem-dep.C
@@ -0,0 +1,57 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// operators that are not required to be members
+// called in a dependent context (as non dependent exprs)
+// see header
+#include "explicit-obj-ops-non-mem.h"
+
+// noop, indicates which versions are ill-formed
+// I could not find a way to test the invalid cases
+// without requires expressions
+#define TEST_INVALID(X)
+
+template<typename T = void>
+void do_calls()
+{
+  Value value{};
+  TEST_OPS(value)
+  TEST_OPS(static_cast<Value&&>(value))
+  TEST_OPS(static_cast<Value const&>(value))
+  TEST_OPS(static_cast<Value const&&>(value))
+  
+  LRef l_ref{};
+  TEST_OPS(l_ref)
+  TEST_INVALID(static_cast<LRef&&>(l_ref))
+  TEST_INVALID(static_cast<LRef const&>(l_ref))
+  TEST_INVALID(static_cast<LRef const&&>(l_ref))
+
+  RRef r_ref{};
+  TEST_INVALID(r_ref)
+  TEST_OPS(static_cast<RRef&&>(r_ref))
+  TEST_INVALID(static_cast<RRef const&>(r_ref))
+  TEST_INVALID(static_cast<RRef const&&>(r_ref))
+
+  ConstLRef const_l_ref{};
+  TEST_OPS(const_l_ref)
+  TEST_OPS(static_cast<ConstLRef&&>(const_l_ref))
+  TEST_OPS(static_cast<ConstLRef const&>(const_l_ref))
+  TEST_OPS(static_cast<ConstLRef const&&>(const_l_ref))
+
+  ConstRRef const_r_ref{};
+  TEST_INVALID(const_r_ref)
+  TEST_INVALID(static_cast<ConstRRef&&>(const_r_ref))
+  TEST_INVALID(static_cast<ConstRRef const&>(const_r_ref))
+  TEST_OPS(static_cast<ConstRRef const&&>(const_r_ref))
+
+  Deduced deduced{};
+  TEST_OPS(deduced)
+  TEST_OPS(static_cast<Deduced&&>(deduced))
+  TEST_OPS(static_cast<Deduced const&>(deduced))
+  TEST_OPS(static_cast<Deduced const&&>(deduced))
+
+  VALIDATE_RETURN_TYPES(deduced, Deduced&)
+  VALIDATE_RETURN_TYPES(static_cast<Deduced&&>(deduced), Deduced&&)
+  VALIDATE_RETURN_TYPES(static_cast<Deduced const&>(deduced), Deduced const&)
+  VALIDATE_RETURN_TYPES(static_cast<Deduced const&&>(deduced), Deduced const&&)
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem-non-dep.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem-non-dep.C
new file mode 100644
index 00000000000..790a6ec379f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem-non-dep.C
@@ -0,0 +1,56 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// operators that are not required to be members
+// called in a non-dependent context
+// see header
+#include "explicit-obj-ops-non-mem.h"
+
+// noop, indicates which versions are ill-formed
+// I could not find a way to test the invalid cases
+// without requires expressions
+#define TEST_INVALID(X)
+
+void do_calls()
+{
+  Value value{};
+  TEST_OPS(value)
+  TEST_OPS(static_cast<Value&&>(value))
+  TEST_OPS(static_cast<Value const&>(value))
+  TEST_OPS(static_cast<Value const&&>(value))
+  
+  LRef l_ref{};
+  TEST_OPS(l_ref)
+  TEST_INVALID(static_cast<LRef&&>(l_ref))
+  TEST_INVALID(static_cast<LRef const&>(l_ref))
+  TEST_INVALID(static_cast<LRef const&&>(l_ref))
+
+  RRef r_ref{};
+  TEST_INVALID(r_ref)
+  TEST_OPS(static_cast<RRef&&>(r_ref))
+  TEST_INVALID(static_cast<RRef const&>(r_ref))
+  TEST_INVALID(static_cast<RRef const&&>(r_ref))
+
+  ConstLRef const_l_ref{};
+  TEST_OPS(const_l_ref)
+  TEST_OPS(static_cast<ConstLRef&&>(const_l_ref))
+  TEST_OPS(static_cast<ConstLRef const&>(const_l_ref))
+  TEST_OPS(static_cast<ConstLRef const&&>(const_l_ref))
+
+  ConstRRef const_r_ref{};
+  TEST_INVALID(const_r_ref)
+  TEST_INVALID(static_cast<ConstRRef&&>(const_r_ref))
+  TEST_INVALID(static_cast<ConstRRef const&>(const_r_ref))
+  TEST_OPS(static_cast<ConstRRef const&&>(const_r_ref))
+
+  Deduced deduced{};
+  TEST_OPS(deduced)
+  TEST_OPS(static_cast<Deduced&&>(deduced))
+  TEST_OPS(static_cast<Deduced const&>(deduced))
+  TEST_OPS(static_cast<Deduced const&&>(deduced))
+
+  VALIDATE_RETURN_TYPES(deduced, Deduced&)
+  VALIDATE_RETURN_TYPES(static_cast<Deduced&&>(deduced), Deduced&&)
+  VALIDATE_RETURN_TYPES(static_cast<Deduced const&>(deduced), Deduced const&)
+  VALIDATE_RETURN_TYPES(static_cast<Deduced const&&>(deduced), Deduced const&&)
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem.h b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem.h
new file mode 100644
index 00000000000..b94e56b1dd6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-non-mem.h
@@ -0,0 +1,202 @@
+// missing test for three-way-compare (I don't know how to write it)
+// missing test for ->* (I don't know how to write it)
+
+// tests for ops that must be member functions are seperate
+
+#define MAKE_STRUCT_OPS(TYPE) \
+  TYPE operator+=(this TYPE self, int) { return self; }		\
+  TYPE operator-=(this TYPE self, int) { return self; }		\
+  TYPE operator*=(this TYPE self, int) { return self; }		\
+  TYPE operator/=(this TYPE self, int) { return self; }		\
+  TYPE operator%=(this TYPE self, int) { return self; }		\
+  TYPE operator&=(this TYPE self, int) { return self; }		\
+  TYPE operator|=(this TYPE self, int) { return self; }		\
+  TYPE operator^=(this TYPE self, int) { return self; }		\
+  TYPE operator<<=(this TYPE self, int) { return self; }	\
+  TYPE operator>>=(this TYPE self, int) { return self; }	\
+  TYPE operator++(this TYPE self) { return self; }		\
+  TYPE operator--(this TYPE self) { return self; }		\
+  TYPE operator++(this TYPE self, int) { return self; }		\
+  TYPE operator--(this TYPE self, int) { return self; }		\
+  TYPE operator+(this TYPE self) { return self; }		\
+  TYPE operator-(this TYPE self) { return self; }		\
+  TYPE operator+(this TYPE self, int) { return self; }		\
+  TYPE operator-(this TYPE self, int) { return self; }		\
+  TYPE operator*(this TYPE self, int) { return self; }		\
+  TYPE operator/(this TYPE self, int) { return self; }		\
+  TYPE operator%(this TYPE self, int) { return self; }		\
+  TYPE operator&(this TYPE self, int) { return self; }		\
+  TYPE operator|(this TYPE self, int) { return self; }		\
+  TYPE operator^(this TYPE self, int) { return self; }		\
+  TYPE operator<<(this TYPE self, int) { return self; }		\
+  TYPE operator>>(this TYPE self, int) { return self; }		\
+  TYPE operator!(this TYPE self) { return self; }		\
+  TYPE operator&&(this TYPE self, int const&) { return self; }	\
+  TYPE operator||(this TYPE self, int const&) { return self; }	\
+  TYPE operator==(this TYPE self, int) { return self; }		\
+  TYPE operator!=(this TYPE self, int) { return self; }		\
+  TYPE operator<(this TYPE self, int) { return self; }		\
+  TYPE operator>(this TYPE self, int) { return self; }		\
+  TYPE operator<=(this TYPE self, int) { return self; }		\
+  TYPE operator>=(this TYPE self, int) { return self; }		\
+  TYPE operator*(this TYPE self) { return self; }		\
+  TYPE operator&(this TYPE self) { return self; }		\
+  TYPE operator,(this TYPE self, int) { return self; }
+
+struct Value {
+  MAKE_STRUCT_OPS (Value)
+};
+
+struct LRef {
+  MAKE_STRUCT_OPS (LRef&)
+};
+
+struct RRef {
+  MAKE_STRUCT_OPS (RRef&&)
+};
+
+struct ConstLRef {
+  MAKE_STRUCT_OPS (ConstLRef const&)
+};
+
+struct ConstRRef {
+  MAKE_STRUCT_OPS (ConstRRef const&&)
+};
+
+#undef MAKE_STRUCT_OPS
+
+struct Deduced {
+  template<typename Self> Self&& operator+=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator-=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator*=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator/=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator%=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator&=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator|=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator^=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator<<=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator>>=(this Self&& self, int) { return static_cast<Self&&>(self); }
+
+  template<typename Self> Self&& operator++(this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator--(this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator++(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator--(this Self&& self, int) { return static_cast<Self&&>(self); }
+
+  template<typename Self> Self&& operator+(this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator-(this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator+(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator-(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator*(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator/(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator%(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator&(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator|(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator^(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator<<(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator>>(this Self&& self, int) { return static_cast<Self&&>(self); }
+
+  template<typename Self> Self&& operator!(this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator&&(this Self&& self, int const&) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator||(this Self&& self, int const&) { return static_cast<Self&&>(self); }
+
+  template<typename Self> Self&& operator==(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator!=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator<(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator>(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator<=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator>=(this Self&& self, int) { return static_cast<Self&&>(self); }
+
+  template<typename Self> Self&& operator*(this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator&(this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self> Self&& operator,(this Self&& self, int) { return static_cast<Self&&>(self); }
+};
+
+#define TEST_OPS(OPERAND) \
+  (OPERAND) += 0;	\
+  (OPERAND) -= 0;	\
+  (OPERAND) *= 0;	\
+  (OPERAND) /= 0;	\
+  (OPERAND) %= 0;	\
+  (OPERAND) &= 0;	\
+  (OPERAND) |= 0;	\
+  (OPERAND) ^= 0;	\
+  (OPERAND) <<= 0;	\
+  (OPERAND) >>= 0;	\
+			\
+  ++(OPERAND);		\
+  --(OPERAND);		\
+  (OPERAND)++;		\
+  (OPERAND)--;		\
+			\
+  +(OPERAND);		\
+  -(OPERAND);		\
+  (OPERAND) + 0;	\
+  (OPERAND) - 0;	\
+  (OPERAND) * 0;	\
+  (OPERAND) / 0;	\
+  (OPERAND) % 0;	\
+  (OPERAND) & 0;	\
+  (OPERAND) | 0;	\
+  (OPERAND) ^ 0;	\
+  (OPERAND) << 0;	\
+  (OPERAND) >> 0;	\
+			\
+  !(OPERAND);		\
+  (OPERAND) && 0;	\
+  (OPERAND) || 0;	\
+			\
+  (OPERAND) == 0;	\
+  (OPERAND) != 0;	\
+  (OPERAND) < 0;	\
+  (OPERAND) > 0;	\
+  (OPERAND) <= 0;	\
+  (OPERAND) >= 0;	\
+			\
+  *(OPERAND);		\
+  &(OPERAND);		\
+  (OPERAND), 0;
+
+#define VALIDATE_RETURN_TYPES(OPERAND, CORRECT_TYPE) \
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) += 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) -= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) *= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) /= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) %= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) &= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) |= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) ^= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) <<= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) >>= 0)));		\
+										\
+  static_assert(__is_same(CORRECT_TYPE, decltype(++(OPERAND))));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype(--(OPERAND))));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND)++)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND)--)));		\
+										\
+  static_assert(__is_same(CORRECT_TYPE, decltype(+(OPERAND))));			\
+  static_assert(__is_same(CORRECT_TYPE, decltype(-(OPERAND))));			\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) + 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) - 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) * 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) / 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) % 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) & 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) | 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) ^ 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) << 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) >> 0)));		\
+										\
+  static_assert(__is_same(CORRECT_TYPE, decltype(!(OPERAND))));			\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) && 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) || 0)));		\
+										\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) == 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) != 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) < 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) > 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) <= 0)));		\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND) >= 0)));		\
+										\
+  static_assert(__is_same(CORRECT_TYPE, decltype(*(OPERAND))));			\
+  static_assert(__is_same(CORRECT_TYPE, decltype(&(OPERAND))));			\
+  static_assert(__is_same(CORRECT_TYPE, decltype((OPERAND), 0)));
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-requires-mem.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-requires-mem.C
new file mode 100644
index 00000000000..b5f88c38f32
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-requires-mem.C
@@ -0,0 +1,172 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// well-formed and ill-formed uses of member only operators in a requires expression
+
+// suppress the warning for Value's arrow operator
+// { dg-options "-Wno-return-local-addr" }
+
+// { dg-excess-errors "Known issue with operators" { xfail *-*-* } }
+
+// It's very hard to test for incorrect successes without requires, and by extension a non dependent variable
+// so for the time being, there are no non dependent tests invalid calls.
+
+struct Value {
+  int _v;
+  Value operator=(this Value self, int) { return self; }
+  Value operator()(this Value self) { return self; }
+  Value operator[](this Value self) { return self; }
+  Value* operator->(this Value self) { return &self; }
+};
+
+struct LRef {
+  int _v;
+  LRef& operator=(this LRef& self, int) { return self; }
+  LRef& operator()(this LRef& self) { return self; }
+  LRef& operator[](this LRef& self) { return self; }
+  LRef* operator->(this LRef& self) { return &self; }
+};
+
+struct RRef {
+  int _v;
+  RRef&& operator=(this RRef&& self, int) { return static_cast<RRef&&>(self); }
+  RRef&& operator()(this RRef&& self) { return static_cast<RRef&&>(self) }
+  RRef&& operator[](this RRef&& self) { return static_cast<RRef&&>(self) }
+  RRef* operator->(this RRef&& self) { return &self; }
+};
+
+struct ConstLRef {
+  int _v;
+  ConstLRef const& operator=(this ConstLRef const& self, int) { return self; }
+  ConstLRef const& operator()(this ConstLRef const& self) { return self; }
+  ConstLRef const& operator[](this ConstLRef const& self) { return self; }
+  ConstLRef const* operator->(this ConstLRef const& self) { return &self; }
+};
+
+struct ConstRRef {
+  int _v;
+  ConstRRef const&& operator=(this ConstRRef const&& self, int) { return static_cast<ConstRRef const&&>(self); }
+  ConstRRef const&& operator()(this ConstRRef const&& self) { return static_cast<ConstRRef const&&>(self); }
+  ConstRRef const&& operator[](this ConstRRef const&& self) { return static_cast<ConstRRef const&&>(self); }
+  ConstRRef const* operator->(this ConstRRef const&& self) { return &self; }
+};
+
+// needed to implement deduced operator->
+template<typename T> struct remove_ref { using type = T; };
+template<typename T> struct remove_ref<T&> { using type = T; };
+template<typename T> struct remove_ref<T&&> { using type = T; };
+template<typename T> using remove_ref_t = typename remove_ref<T>::type;
+
+struct Deduced {
+  int _v;
+  template<typename Self>
+  Self&& operator=(this Self&& self, int) { return static_cast<Self&&>(self); }
+  template<typename Self>
+  Self&& operator()(this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self>
+  Self&& operator[](this Self&& self) { return static_cast<Self&&>(self); }
+  template<typename Self>
+  remove_ref_t<Self>* operator->(this Self&& self) { return &self; }
+};
+
+#define TEST_INVALID(OPERAND) \
+  static_assert(!requires{ (OPERAND) = 0; }, "Unexpected success calling operator = with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND)(); }, "Unexpected success calling operator () with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND)[]; }, "Unexpected success calling operator [] with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND)->_v; }, "Unexpected success calling operator -> with " #OPERAND);
+
+#define TEST_VALID(OPERAND) \
+  static_assert(requires{ (OPERAND) = 0; }, "Unexpected failure calling operator = with " #OPERAND);	\
+  static_assert(requires{ (OPERAND)(); }, "Unexpected failure calling operator () with " #OPERAND);	\
+  static_assert(requires{ (OPERAND)[]; }, "Unexpected failure calling operator [] with " #OPERAND);	\
+  static_assert(requires{ (OPERAND)->_v; }, "Unexpected failure calling operator -> with " #OPERAND);
+
+template<typename T, typename U>
+concept same_as = __is_same(T, U);
+
+#define TEST_VALID_WITH_RETURN_TYPES(OPERAND, CORRECT_TYPE) \
+  static_assert(requires{ {(OPERAND) = 0} -> same_as<CORRECT_TYPE>; },"Unexpected failure with return type check calling operator = with " #OPERAND " -> expected return type: " #CORRECT_TYPE);	\
+  static_assert(requires{ {(OPERAND)()} -> same_as<CORRECT_TYPE>; },  "Unexpected failure with return type check calling operator () with " #OPERAND " -> expected return type: " #CORRECT_TYPE);	\
+  static_assert(requires{ {(OPERAND)[]} -> same_as<CORRECT_TYPE>; },  "Unexpected failure with return type check calling operator [] with " #OPERAND " -> expected return type: " #CORRECT_TYPE);
+  
+
+template<typename DepValue = Value>
+void test_value()
+{
+  DepValue value{};
+  TEST_VALID(value)
+  TEST_VALID(static_cast<DepValue&&>(value))
+  TEST_VALID(static_cast<DepValue const&>(value))
+  TEST_VALID(static_cast<DepValue const&&>(value))
+}
+
+template<typename DepLRef = LRef>
+void test_l_ref()
+{
+  DepLRef l_ref{};
+  TEST_VALID(l_ref)
+  TEST_INVALID(static_cast<DepLRef&&>(l_ref))
+  TEST_INVALID(static_cast<DepLRef const&>(l_ref))
+  TEST_INVALID(static_cast<DepLRef const&&>(l_ref))
+}
+
+template<typename DepRRef = RRef>
+void test_r_ref()
+{
+  DepRRef r_ref{};
+  TEST_INVALID(r_ref)
+  TEST_VALID(static_cast<DepRRef&&>(r_ref))
+  TEST_INVALID(static_cast<DepRRef const&>(r_ref))
+  TEST_INVALID(static_cast<DepRRef const&&>(r_ref))
+}
+
+template<typename DepConstLRef = ConstLRef>
+void test_const_l_ref()
+{
+  DepConstLRef const_l_ref{};
+  TEST_VALID(const_l_ref)
+  TEST_VALID(static_cast<DepConstLRef&&>(const_l_ref))
+  TEST_VALID(static_cast<DepConstLRef const&>(const_l_ref))
+  TEST_VALID(static_cast<DepConstLRef const&&>(const_l_ref))
+}
+
+template<typename DepConstRRef = ConstRRef>
+void test_const_r_ref()
+{
+  DepConstRRef const_r_ref{};
+  TEST_INVALID(const_r_ref)
+  TEST_INVALID(static_cast<DepConstRRef&&>(const_r_ref))
+  TEST_INVALID(static_cast<DepConstRRef const&>(const_r_ref))
+  TEST_VALID(static_cast<DepConstRRef const&&>(const_r_ref))
+}
+
+template<typename DepDeduced = Deduced>
+void test_deduced()
+{
+  DepDeduced deduced{};
+
+  TEST_VALID(deduced)
+  TEST_VALID(static_cast<DepDeduced&&>(deduced))
+  TEST_VALID(static_cast<DepDeduced const&>(deduced))
+  TEST_VALID(static_cast<DepDeduced const&&>(deduced))
+
+  TEST_VALID_WITH_RETURN_TYPES(deduced, DepDeduced&)
+  TEST_VALID_WITH_RETURN_TYPES(static_cast<DepDeduced&&>(deduced), DepDeduced&&)
+  TEST_VALID_WITH_RETURN_TYPES(static_cast<DepDeduced const&>(deduced), DepDeduced const&)
+  TEST_VALID_WITH_RETURN_TYPES(static_cast<DepDeduced const&&>(deduced), DepDeduced const&&)
+  // arrow operator needs to be seperate to check the type of _v
+  static_assert(requires{ {(deduced->_v)} -> same_as<int&>; }, "Unexpected failure with return type check calling operator -> with deduced->_v");
+  static_assert(requires{ {(static_cast<DepDeduced&&>(deduced)->_v)} -> same_as<int const&>; }, "Unexpected failure with return type check calling operator -> with static_cast<DepDeduced&&>(deduced)->_v");
+  static_assert(requires{ {(static_cast<DepDeduced const&>(deduced)->_v)} -> same_as<int&>; }, "Unexpected failure with return type check calling operator -> with static_cast<DepDeduced const&>(deduced)->_v");
+  static_assert(requires{ {(static_cast<DepDeduced const&&>(deduced)->_v)} -> same_as<int const&>; }, "Unexpected failure with return type check calling operator -> with static_cast<DepDeduced const&&>(deduced)->_v");
+}
+
+void test()
+{
+  test_value();
+  test_l_ref();
+  test_r_ref();
+  test_const_l_ref();
+  test_const_r_ref();
+  test_deduced();
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-requires-non-mem.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-requires-non-mem.C
new file mode 100644
index 00000000000..981ab39b79d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-ops-requires-non-mem.C
@@ -0,0 +1,229 @@
+// P0847R7
+// { dg-do compile { target c++23 } }
+
+// well-formed and ill-formed uses of non-member capable operators in a requires expression
+
+// { dg-excess-errors "Known issue with operators" { xfail *-*-* } }
+
+#include "explicit-obj-ops-non-mem.h"
+
+// we only need the structs from the header
+#undef TEST_OPS
+#undef VALIDATE_RETURN_TYPES
+
+// It's very hard to test for incorrect successes without requires, and by extension a non dependent variable
+// so for the time being, there are no non dependent tests invalid calls.
+
+#define TEST_INVALID(OPERAND) \
+  static_assert(!requires{ (OPERAND) += 0; }, "Unexpected success calling operator += with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) -= 0; }, "Unexpected success calling operator -= with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) *= 0; }, "Unexpected success calling operator *= with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) /= 0; }, "Unexpected success calling operator /= with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) %= 0; }, "Unexpected success calling operator %= with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) &= 0; }, "Unexpected success calling operator &= with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) |= 0; }, "Unexpected success calling operator |= with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) ^= 0; }, "Unexpected success calling operator ^= with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) <<= 0; }, "Unexpected success calling operator <<= with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND) >>= 0; }, "Unexpected success calling operator >>= with " #OPERAND);	\
+														\
+  static_assert(!requires{ ++(OPERAND); }, "Unexpected success calling operator pre++ with " #OPERAND);		\
+  static_assert(!requires{ --(OPERAND); }, "Unexpected success calling operator pre-- with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND)++; }, "Unexpected success calling operator post++ with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND)--; }, "Unexpected success calling operator post-- with " #OPERAND);	\
+														\
+  static_assert(!requires{ +(OPERAND); }, "Unexpected success calling operator unary+ with " #OPERAND);		\
+  static_assert(!requires{ -(OPERAND); }, "Unexpected success calling operator unary- with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) + 0; }, "Unexpected success calling operator binary+ with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND) - 0; }, "Unexpected success calling operator binary- with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND) * 0; }, "Unexpected success calling operator binary* with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND) / 0; }, "Unexpected success calling operator / with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) % 0; }, "Unexpected success calling operator % with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) & 0; }, "Unexpected success calling operator binary& with " #OPERAND);	\
+  static_assert(!requires{ (OPERAND) | 0; }, "Unexpected success calling operator | with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) ^ 0; }, "Unexpected success calling operator ^ with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) << 0; }, "Unexpected success calling operator << with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) >> 0; }, "Unexpected success calling operator >> with " #OPERAND);		\
+														\
+  static_assert(!requires{ !(OPERAND); }, "Unexpected success calling operator ! with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) && 0; }, "Unexpected success calling operator && with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) || 0; }, "Unexpected success calling operator || with " #OPERAND);		\
+														\
+  static_assert(!requires{ (OPERAND) == 0; }, "Unexpected success calling operator == with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) != 0; }, "Unexpected success calling operator != with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) < 0; }, "Unexpected success calling operator < with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) > 0; }, "Unexpected success calling operator > with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) <= 0; }, "Unexpected success calling operator <= with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND) >= 0; }, "Unexpected success calling operator >= with " #OPERAND);		\
+														\
+  static_assert(!requires{ *(OPERAND); }, "Unexpected success calling operator unary* with " #OPERAND);		\
+  static_assert(!requires{ &(OPERAND); }, "Unexpected success calling operator unary& with " #OPERAND);		\
+  static_assert(!requires{ (OPERAND), 0; }, "Unexpected success calling operator , with " #OPERAND);
+
+#define TEST_VALID(OPERAND) \
+  static_assert(requires{ (OPERAND) += 0; }, "Unexpected failure calling operator += with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) -= 0; }, "Unexpected failure calling operator -= with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) *= 0; }, "Unexpected failure calling operator *= with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) /= 0; }, "Unexpected failure calling operator /= with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) %= 0; }, "Unexpected failure calling operator %= with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) &= 0; }, "Unexpected failure calling operator &= with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) |= 0; }, "Unexpected failure calling operator |= with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) ^= 0; }, "Unexpected failure calling operator ^= with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) <<= 0; }, "Unexpected failure calling operator <<= with " #OPERAND);	\
+  static_assert(requires{ (OPERAND) >>= 0; }, "Unexpected failure calling operator >>= with " #OPERAND);	\
+														\
+  static_assert(requires{ ++(OPERAND); }, "Unexpected failure calling operator pre++ with " #OPERAND);		\
+  static_assert(requires{ --(OPERAND); }, "Unexpected failure calling operator pre-- with " #OPERAND);		\
+  static_assert(requires{ (OPERAND)++; }, "Unexpected failure calling operator post++ with " #OPERAND);		\
+  static_assert(requires{ (OPERAND)--; }, "Unexpected failure calling operator post-- with " #OPERAND);		\
+														\
+  static_assert(requires{ +(OPERAND); }, "Unexpected failure calling operator unary+ with " #OPERAND);		\
+  static_assert(requires{ -(OPERAND); }, "Unexpected failure calling operator unary- with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) + 0; }, "Unexpected failure calling operator binary+ with " #OPERAND);	\
+  static_assert(requires{ (OPERAND) - 0; }, "Unexpected failure calling operator binary- with " #OPERAND);	\
+  static_assert(requires{ (OPERAND) * 0; }, "Unexpected failure calling operator binary* with " #OPERAND);	\
+  static_assert(requires{ (OPERAND) / 0; }, "Unexpected failure calling operator / with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) % 0; }, "Unexpected failure calling operator % with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) & 0; }, "Unexpected failure calling operator binary& with " #OPERAND);	\
+  static_assert(requires{ (OPERAND) | 0; }, "Unexpected failure calling operator | with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) ^ 0; }, "Unexpected failure calling operator ^ with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) << 0; }, "Unexpected failure calling operator << with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) >> 0; }, "Unexpected failure calling operator >> with " #OPERAND);		\
+														\
+  static_assert(requires{ !(OPERAND); }, "Unexpected failure calling operator ! with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) && 0; }, "Unexpected failure calling operator && with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) || 0; }, "Unexpected failure calling operator || with " #OPERAND);		\
+														\
+  static_assert(requires{ (OPERAND) == 0; }, "Unexpected failure calling operator == with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) != 0; }, "Unexpected failure calling operator != with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) < 0; }, "Unexpected failure calling operator < with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) > 0; }, "Unexpected failure calling operator > with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) <= 0; }, "Unexpected failure calling operator <= with " #OPERAND);		\
+  static_assert(requires{ (OPERAND) >= 0; }, "Unexpected failure calling operator >= with " #OPERAND);		\
+														\
+  static_assert(requires{ *(OPERAND); }, "Unexpected failure calling operator unary* with " #OPERAND);		\
+  static_assert(requires{ &(OPERAND); }, "Unexpected failure calling operator unary& with " #OPERAND);		\
+  static_assert(requires{ (OPERAND), 0; }, "Unexpected failure calling operator , with " #OPERAND);
+
+template<typename T, typename U>
+concept same_as = __is_same(T, U);
+
+#define TEST_VALID_WITH_RETURN_TYPES(OPERAND, CORRECT_TYPE) \
+  static_assert(requires{ {(OPERAND) += 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) -= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) *= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) /= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) %= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) &= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) |= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) ^= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) <<= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) >>= 0} -> same_as<CORRECT_TYPE>; });	\
+										\
+  static_assert(requires{ {++(OPERAND)} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {--(OPERAND)} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND)++} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND)--} -> same_as<CORRECT_TYPE>; });		\
+										\
+  static_assert(requires{ {+(OPERAND)} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {-(OPERAND)} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) + 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) - 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) * 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) / 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) % 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) & 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) | 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) ^ 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) << 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) >> 0} -> same_as<CORRECT_TYPE>; });	\
+										\
+  static_assert(requires{ {!(OPERAND)} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) && 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) || 0} -> same_as<CORRECT_TYPE>; });	\
+										\
+  static_assert(requires{ {(OPERAND) == 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) != 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) < 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) > 0} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND) <= 0} -> same_as<CORRECT_TYPE>; });	\
+  static_assert(requires{ {(OPERAND) >= 0} -> same_as<CORRECT_TYPE>; });	\
+										\
+  static_assert(requires{ {*(OPERAND)} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {&(OPERAND)} -> same_as<CORRECT_TYPE>; });		\
+  static_assert(requires{ {(OPERAND), 0} -> same_as<CORRECT_TYPE>; });
+
+template<typename DepValue = Value>
+void test_value()
+{
+  DepValue value{};
+  TEST_VALID(value)
+  TEST_VALID(static_cast<DepValue&&>(value))
+  TEST_VALID(static_cast<DepValue const&>(value))
+  TEST_VALID(static_cast<DepValue const&&>(value))
+}
+
+template<typename DepLRef = LRef>
+void test_l_ref()
+{
+  DepLRef l_ref{};
+  TEST_VALID(l_ref)
+  TEST_INVALID(static_cast<DepLRef&&>(l_ref))
+  TEST_INVALID(static_cast<DepLRef const&>(l_ref))
+  TEST_INVALID(static_cast<DepLRef const&&>(l_ref))
+}
+
+template<typename DepRRef = RRef>
+void test_r_ref()
+{
+  DepRRef r_ref{};
+  TEST_INVALID(r_ref)
+  TEST_VALID(static_cast<DepRRef&&>(r_ref))
+  TEST_INVALID(static_cast<DepRRef const&>(r_ref))
+  TEST_INVALID(static_cast<DepRRef const&&>(r_ref))
+}
+
+template<typename DepConstLRef = ConstLRef>
+void test_const_l_ref()
+{
+  DepConstLRef const_l_ref{};
+  TEST_VALID(const_l_ref)
+  TEST_VALID(static_cast<DepConstLRef&&>(const_l_ref))
+  TEST_VALID(static_cast<DepConstLRef const&>(const_l_ref))
+  TEST_VALID(static_cast<DepConstLRef const&&>(const_l_ref))
+}
+
+template<typename DepConstRRef = ConstRRef>
+void test_const_r_ref()
+{
+  DepConstRRef const_r_ref{};
+  TEST_INVALID(const_r_ref)
+  TEST_INVALID(static_cast<DepConstRRef&&>(const_r_ref))
+  TEST_INVALID(static_cast<DepConstRRef const&>(const_r_ref))
+  TEST_VALID(static_cast<DepConstRRef const&&>(const_r_ref))
+}
+
+template<typename DepDeduced = Deduced>
+void test_deduced()
+{
+  DepDeduced deduced{};
+
+  TEST_VALID(deduced)
+  TEST_VALID(static_cast<DepDeduced&&>(deduced))
+  TEST_VALID(static_cast<DepDeduced const&>(deduced))
+  TEST_VALID(static_cast<DepDeduced const&&>(deduced))
+
+  TEST_VALID_WITH_RETURN_TYPES(deduced, DepDeduced&)
+  TEST_VALID_WITH_RETURN_TYPES(static_cast<DepDeduced&&>(deduced), DepDeduced&&)
+  TEST_VALID_WITH_RETURN_TYPES(static_cast<DepDeduced const&>(deduced), DepDeduced const&)
+  TEST_VALID_WITH_RETURN_TYPES(static_cast<DepDeduced const&&>(deduced), DepDeduced const&&)
+}
+
+void test()
+{
+  test_value();
+  test_l_ref();
+  test_r_ref();
+  test_const_l_ref();
+  test_const_r_ref();
+  test_deduced();
+}
-- 
2.42.0

