[v23,32/33] c++: Implement __is_invocable built-in trait
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Commit Message
This patch implements built-in trait for std::is_invocable.
gcc/cp/ChangeLog:
* cp-trait.def: Define __is_invocable.
* constraint.cc (diagnose_trait_expr): Handle CPTK_IS_INVOCABLE.
* semantics.cc (trait_expr_value): Likewise.
(finish_trait_expr): Likewise.
(is_invocable_p): New function.
* method.h: New file to export build_trait_object in method.cc.
gcc/testsuite/ChangeLog:
* g++.dg/ext/has-builtin-1.C: Test existence of __is_invocable.
* g++.dg/ext/is_invocable1.C: New test.
* g++.dg/ext/is_invocable2.C: New test.
* g++.dg/ext/is_invocable3.C: New test.
* g++.dg/ext/is_invocable4.C: New test.
Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
gcc/cp/constraint.cc | 6 +
gcc/cp/cp-trait.def | 1 +
gcc/cp/method.h | 28 ++
gcc/cp/semantics.cc | 135 +++++++++
gcc/testsuite/g++.dg/ext/has-builtin-1.C | 3 +
gcc/testsuite/g++.dg/ext/is_invocable1.C | 337 +++++++++++++++++++++++
gcc/testsuite/g++.dg/ext/is_invocable2.C | 139 ++++++++++
gcc/testsuite/g++.dg/ext/is_invocable3.C | 51 ++++
gcc/testsuite/g++.dg/ext/is_invocable4.C | 33 +++
9 files changed, 733 insertions(+)
create mode 100644 gcc/cp/method.h
create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable1.C
create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable2.C
create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable3.C
create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable4.C
Comments
On Fri, 20 Oct 2023, Ken Matsui wrote:
> This patch implements built-in trait for std::is_invocable.
Nice! My email client unfortunately ate my first review attempt, so
apologies for my brevity this time around.
> gcc/cp/ChangeLog:
>
> * cp-trait.def: Define __is_invocable.
> * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_INVOCABLE.
> * semantics.cc (trait_expr_value): Likewise.
> (finish_trait_expr): Likewise.
> (is_invocable_p): New function.
> * method.h: New file to export build_trait_object in method.cc.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/ext/has-builtin-1.C: Test existence of __is_invocable.
> * g++.dg/ext/is_invocable1.C: New test.
> * g++.dg/ext/is_invocable2.C: New test.
> * g++.dg/ext/is_invocable3.C: New test.
> * g++.dg/ext/is_invocable4.C: New test.
>
> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> ---
> gcc/cp/constraint.cc | 6 +
> gcc/cp/cp-trait.def | 1 +
> gcc/cp/method.h | 28 ++
> gcc/cp/semantics.cc | 135 +++++++++
> gcc/testsuite/g++.dg/ext/has-builtin-1.C | 3 +
> gcc/testsuite/g++.dg/ext/is_invocable1.C | 337 +++++++++++++++++++++++
> gcc/testsuite/g++.dg/ext/is_invocable2.C | 139 ++++++++++
> gcc/testsuite/g++.dg/ext/is_invocable3.C | 51 ++++
> gcc/testsuite/g++.dg/ext/is_invocable4.C | 33 +++
> 9 files changed, 733 insertions(+)
> create mode 100644 gcc/cp/method.h
> create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable1.C
> create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable2.C
> create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable3.C
> create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable4.C
>
> diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> index 9fce36e12d1..29bf548d30a 100644
> --- a/gcc/cp/constraint.cc
> +++ b/gcc/cp/constraint.cc
> @@ -3754,6 +3754,12 @@ diagnose_trait_expr (tree expr, tree args)
> case CPTK_IS_FUNCTION:
> inform (loc, " %qT is not a function", t1);
> break;
> + case CPTK_IS_INVOCABLE:
> + if (!t2)
> + inform (loc, " %qT is not invocable", t1);
> + else
> + inform (loc, " %qT is not invocable by %qE", t1, t2);
> + break;
> case CPTK_IS_LAYOUT_COMPATIBLE:
> inform (loc, " %qT is not layout compatible with %qT", t1, t2);
> break;
> diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> index 05514a51c21..b8b7608c122 100644
> --- a/gcc/cp/cp-trait.def
> +++ b/gcc/cp/cp-trait.def
> @@ -71,6 +71,7 @@ DEFTRAIT_EXPR (IS_EMPTY, "__is_empty", 1)
> DEFTRAIT_EXPR (IS_ENUM, "__is_enum", 1)
> DEFTRAIT_EXPR (IS_FINAL, "__is_final", 1)
> DEFTRAIT_EXPR (IS_FUNCTION, "__is_function", 1)
> +DEFTRAIT_EXPR (IS_INVOCABLE, "__is_invocable", -1)
> DEFTRAIT_EXPR (IS_LAYOUT_COMPATIBLE, "__is_layout_compatible", 2)
> DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 1)
> DEFTRAIT_EXPR (IS_MEMBER_FUNCTION_POINTER, "__is_member_function_pointer", 1)
> diff --git a/gcc/cp/method.h b/gcc/cp/method.h
> new file mode 100644
> index 00000000000..1aec8ec5cfd
> --- /dev/null
> +++ b/gcc/cp/method.h
> @@ -0,0 +1,28 @@
> +/* Functions exported by method.cc.
> + Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify
> +it under the terms of the GNU General Public License as published by
> +the Free Software Foundation; either version 3, or (at your option)
> +any later version.
> +
> +GCC is distributed in the hope that it will be useful,
> +but WITHOUT ANY WARRANTY; without even the implied warranty of
> +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +GNU General Public License for more details.
> +
> +You should have received a copy of the GNU General Public License
> +along with GCC; see the file COPYING3. If not see
> +<http://www.gnu.org/licenses/>. */
> +
> +#ifndef GCC_CP_METHOD_H
> +#define GCC_CP_METHOD_H 1
> +
> +#include "tree.h"
> +
> +/* In method.cc */
> +extern tree build_trait_object (tree type);
Since other method.cc exports are already declared in cp-tree.h, for now
let's just declare this in cp-tree.h as well (under build_stub_object)
instead of creating a new header file.
> +
> +#endif /* GCC_CP_METHOD_H */
> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> index 7cccbae5287..cc2e400531a 100644
> --- a/gcc/cp/semantics.cc
> +++ b/gcc/cp/semantics.cc
> @@ -45,6 +45,10 @@ along with GCC; see the file COPYING3. If not see
> #include "gomp-constants.h"
> #include "predict.h"
> #include "memmodel.h"
> +#include "method.h"
> +
> +#include "print-tree.h"
> +#include "tree-pretty-print.h"
>
> /* There routines provide a modular interface to perform many parsing
> operations. They may therefore be used during actual parsing, or
> @@ -11714,6 +11718,133 @@ classtype_has_nothrow_assign_or_copy_p (tree type, bool assign_p)
> return saw_copy;
> }
>
> +/* Return true if FN_TYPE is invocable with the given ARG_TYPES. */
> +
> +static bool
> +is_invocable_p (tree fn_type, tree arg_types)
> +{
> + /* ARG_TYPES must be a TREE_VEC. */
> + gcc_assert (TREE_CODE (arg_types) == TREE_VEC);
> +
> + /* Access check is required to determine if the given is invocable. */
> + deferring_access_check_sentinel acs (dk_no_deferred);
> +
> + /* std::is_invocable is an unevaluated context. */
> + cp_unevaluated cp_uneval_guard;
> +
> + bool is_ptrdatamem;
> + bool is_ptrmemfunc;
> + if (TREE_CODE (fn_type) == REFERENCE_TYPE)
> + {
> + tree deref_fn_type = TREE_TYPE (fn_type);
> + is_ptrdatamem = TYPE_PTRDATAMEM_P (deref_fn_type);
> + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (deref_fn_type);
> +
> + /* Dereference fn_type if it is a pointer to member. */
> + if (is_ptrdatamem || is_ptrmemfunc)
> + fn_type = deref_fn_type;
> + }
> + else
> + {
> + is_ptrdatamem = TYPE_PTRDATAMEM_P (fn_type);
> + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (fn_type);
> + }
> +
> + if (is_ptrdatamem && TREE_VEC_LENGTH (arg_types) != 1)
> + /* A pointer to data member with non-one argument is not invocable. */
> + return false;
> +
> + if (is_ptrmemfunc && TREE_VEC_LENGTH (arg_types) == 0)
> + /* A pointer to member function with no arguments is not invocable. */
> + return false;
> +
> + /* Construct an expression of a pointer to member. */
> + tree datum;
> + if (is_ptrdatamem || is_ptrmemfunc)
> + {
> + tree datum_type = TREE_VEC_ELT (arg_types, 0);
> +
> + /* Dereference datum. */
> + if (CLASS_TYPE_P (datum_type))
> + {
> + bool is_refwrap = false;
> +
> + tree datum_decl = TYPE_NAME (TYPE_MAIN_VARIANT (datum_type));
> + if (decl_in_std_namespace_p (datum_decl))
> + {
> + tree name = DECL_NAME (datum_decl);
> + if (name && (id_equal (name, "reference_wrapper")))
> + {
> + /* Handle std::reference_wrapper. */
> + is_refwrap = true;
> + datum_type = cp_build_reference_type (datum_type, false);
> + }
> + }
> +
> + datum = build_trait_object (datum_type);
> +
> + /* If datum_type was not std::reference_wrapper, check if it has
> + operator*() overload. If datum_type was std::reference_wrapper,
> + avoid dereferencing the datum twice. */
> + if (!is_refwrap)
> + if (get_class_binding (datum_type, get_identifier ("operator*")))
We probably should use lookup_member instead of get_class_binding since
IIUC the latter doesn't look into bases:
struct A { int m; };
struct B { A& operator*(): };
struct C : B { };
static_assert(std::is_invocable_v<int A::*, C>);
However, I notice that the specification of INVOKE
(https://eel.is/c++draft/func.require#lib:INVOKE) doesn't mention name
lookup at all so it strikes me as suspicious that we'd perform name
lookup here. I think this would misbehave for:
struct A { };
struct B : A { A& operator*() = delete; };
static_assert(std::is_invocable_v<int A::*, B>);
struct C : private A { A& operator*(); };
static_assert(std::is_invocable_v<int A::*, C>);
ultimately because we end up choosing the dereference form of INVOKE,
but according to 1.1/1.4 we should choose the non-dereference form?
> + /* Handle operator*(). */
> + datum = build_x_indirect_ref (UNKNOWN_LOCATION, datum,
> + RO_UNARY_STAR, NULL_TREE,
> + tf_none);
> + }
> + else if (POINTER_TYPE_P (datum_type))
> + datum = build_trait_object (TREE_TYPE (datum_type));
> + else
> + datum = build_trait_object (datum_type);
> + }
> +
> + /* Build a function expression. */
> + tree fn;
> + if (is_ptrdatamem)
> + fn = build_m_component_ref (datum, build_trait_object (fn_type), tf_none);
Maybe exit early for the is_ptrdatamem case here (and simplify the rest
of the function accordingly)?
> + else if (is_ptrmemfunc)
> + fn = build_trait_object (TYPE_PTRMEMFUNC_FN_TYPE (fn_type));
> + else
> + fn = build_trait_object (fn_type);
> +
> + /* Construct arguments to the function and an expression of a call. */
> + if (!is_ptrdatamem)
> + {
> + releasing_vec args;
> +
> + if (is_ptrmemfunc)
> + {
> + /* A pointer to member function is internally converted to a pointer
> + to function that takes a pointer to the dereferenced datum type
> + as its first argument and original arguments afterward. If the
> + function is a const member function, the first argument also
> + requires a const datum pointer and vice-versa. */
> +
> + tree datum_type = TREE_TYPE (datum);
> + if (TYPE_REF_P (datum_type))
> + datum_type = TREE_TYPE (datum_type);
> +
> + datum = build_trait_object (build_pointer_type (datum_type));
> + vec_safe_push (args, datum);
> + }
> +
> + for (int i = is_ptrmemfunc ? 1 : 0; i < TREE_VEC_LENGTH (arg_types); ++i)
> + {
> + tree arg_type = TREE_VEC_ELT (arg_types, i);
> + tree arg = build_trait_object (arg_type);
> + vec_safe_push (args, arg);
> + }
> +
> + fn = finish_call_expr (fn, &args, false, false, tf_none);
> + }
> +
> + if (error_operand_p (fn))
> + return false;
> +
> + return true;
> +}
> +
> /* Return true if DERIVED is pointer interconvertible base of BASE. */
>
> static bool
> @@ -12181,6 +12312,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> case CPTK_IS_FUNCTION:
> return type_code1 == FUNCTION_TYPE;
>
> + case CPTK_IS_INVOCABLE:
> + return is_invocable_p (type1, type2);
> +
> case CPTK_IS_LAYOUT_COMPATIBLE:
> return layout_compatible_type_p (type1, type2);
>
> @@ -12390,6 +12524,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
> break;
>
> case CPTK_IS_CONVERTIBLE:
> + case CPTK_IS_INVOCABLE:
> case CPTK_IS_NOTHROW_ASSIGNABLE:
> case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> case CPTK_IS_NOTHROW_CONVERTIBLE:
> diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> index b1430e9bd8b..3a9bda1ee03 100644
> --- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> +++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> @@ -92,6 +92,9 @@
> #if !__has_builtin (__is_function)
> # error "__has_builtin (__is_function) failed"
> #endif
> +#if !__has_builtin (__is_invocable)
> +# error "__has_builtin (__is_invocable) failed"
> +#endif
> #if !__has_builtin (__is_layout_compatible)
> # error "__has_builtin (__is_layout_compatible) failed"
> #endif
> diff --git a/gcc/testsuite/g++.dg/ext/is_invocable1.C b/gcc/testsuite/g++.dg/ext/is_invocable1.C
> new file mode 100644
> index 00000000000..2fd3906b571
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/is_invocable1.C
> @@ -0,0 +1,337 @@
> +// { dg-do compile { target c++11 } }
> +
> +#define SA(X) static_assert((X),#X)
> +
> +using func_type_v0 = void(*)();
> +
> +SA( __is_invocable( func_type_v0 ) );
> +SA( ! __is_invocable( func_type_v0, int ) );
> +
> +using func_type_i0 = int(*)();
> +
> +SA( __is_invocable( func_type_i0 ) );
> +SA( ! __is_invocable( func_type_i0, int ) );
> +
> +using func_type_l0 = int&(*)();
> +
> +SA( __is_invocable( func_type_l0 ) );
> +SA( ! __is_invocable( func_type_l0(int) ) );
> +
> +using func_type_ii = int(*)(int);
> +
> +SA( ! __is_invocable( func_type_ii ) );
> +SA( __is_invocable( func_type_ii, int ) );
> +
> +using func_type_il = int(*)(int&);
> +
> +SA( ! __is_invocable( func_type_il ) );
> +SA( ! __is_invocable( func_type_il, int ) );
> +SA( __is_invocable( func_type_il, int& ) );
> +
> +using func_type_ir = int(*)(int&&);
> +
> +SA( ! __is_invocable( func_type_ir ) );
> +SA( ! __is_invocable( func_type_ir, int& ) );
> +SA( __is_invocable( func_type_ir, int ) );
> +SA( __is_invocable( func_type_ir, int&& ) );
> +
> +struct A { };
> +
> +using mem_type_i = int A::*;
> +
> +SA( ! __is_invocable( mem_type_i ) );
> +SA( ! __is_invocable( mem_type_i, int ) );
> +SA( ! __is_invocable( mem_type_i, int* ) );
> +SA( ! __is_invocable( mem_type_i, int& ) );
> +SA( ! __is_invocable( mem_type_i, int&& ) );
> +SA( __is_invocable( mem_type_i, A ) );
> +SA( __is_invocable( mem_type_i, A* ) );
> +SA( __is_invocable( mem_type_i, A& ) );
> +SA( __is_invocable( mem_type_i, A&& ) );
> +SA( __is_invocable( mem_type_i, const A& ) );
> +SA( ! __is_invocable( mem_type_i, A&, int ) );
> +
> +using memfun_type_i = int (A::*)();
> +
> +SA( ! __is_invocable( memfun_type_i ) );
> +SA( ! __is_invocable( memfun_type_i, int ) );
> +SA( ! __is_invocable( memfun_type_i, int* ) );
> +SA( ! __is_invocable( memfun_type_i, int& ) );
> +SA( ! __is_invocable( memfun_type_i, int&& ) );
> +SA( __is_invocable( memfun_type_i, A ) );
> +SA( __is_invocable( memfun_type_i, A* ) );
> +SA( __is_invocable( memfun_type_i, A& ) );
> +SA( __is_invocable( memfun_type_i, A&& ) );
> +SA( ! __is_invocable( memfun_type_i, const A& ) );
> +SA( ! __is_invocable( memfun_type_i, A&, int ) );
> +
> +using memfun_type_ic = int (A::*)() const;
> +
> +SA( ! __is_invocable( memfun_type_ic ) );
> +SA( ! __is_invocable( memfun_type_ic, int ) );
> +SA( ! __is_invocable( memfun_type_ic, int& ) );
> +SA( __is_invocable( memfun_type_ic, A& ) );
> +SA( __is_invocable( memfun_type_ic, A* ) );
> +SA( ! __is_invocable( memfun_type_ic, A&, int ) );
> +SA( ! __is_invocable( memfun_type_ic, A*, int& ) );
> +SA( __is_invocable( memfun_type_ic, const A& ) );
> +SA( __is_invocable( memfun_type_ic, const A* ) );
> +SA( ! __is_invocable( memfun_type_ic, const A&, int& ) );
> +SA( ! __is_invocable( memfun_type_ic, const A*, int ) );
> +
> +using memfun_type_iic = int& (A::*)(int&) const;
> +
> +SA( ! __is_invocable( memfun_type_iic ) );
> +SA( ! __is_invocable( memfun_type_iic, int ) );
> +SA( ! __is_invocable( memfun_type_iic, int& ) );
> +SA( ! __is_invocable( memfun_type_iic, A&, int ) );
> +SA( __is_invocable( memfun_type_iic, A&, int& ) );
> +SA( ! __is_invocable( memfun_type_iic, A*, int ) );
> +SA( __is_invocable( memfun_type_iic, A*, int& ) );
> +SA( ! __is_invocable( memfun_type_iic, const A&, int ) );
> +SA( ! __is_invocable( memfun_type_iic, const A&, int&, int ) );
> +SA( __is_invocable( memfun_type_iic, const A&, int& ) );
> +SA( __is_invocable( memfun_type_iic, const A*, int& ) );
> +
> +struct B {
> + int& operator()();
> + long& operator()() const;
> + bool& operator()(int);
> +private:
> + void operator()(int, int);
> +};
> +using CB = const B;
> +
> +SA( __is_invocable( B ) );
> +SA( __is_invocable( B& ) );
> +SA( __is_invocable( B&& ) );
> +SA( ! __is_invocable( B* ) );
> +SA( __is_invocable( CB ) );
> +SA( __is_invocable( CB& ) );
> +SA( ! __is_invocable( CB* ) );
> +
> +SA( __is_invocable( B, int ) );
> +SA( __is_invocable( B&, int ) );
> +SA( __is_invocable( B&&, int ) );
> +SA( ! __is_invocable( B*, int ) );
> +SA( ! __is_invocable( CB, int ) );
> +SA( ! __is_invocable( CB&, int ) );
> +SA( ! __is_invocable( CB*, int ) );
> +
> +SA( ! __is_invocable( B, int, int ) );
> +SA( ! __is_invocable( B&, int, int ) );
> +SA( ! __is_invocable( B&&, int, int ) );
> +SA( ! __is_invocable( B*, int, int ) );
> +SA( ! __is_invocable( CB, int, int ) );
> +SA( ! __is_invocable( CB&, int, int ) );
> +SA( ! __is_invocable( CB*, int, int ) );
> +
> +struct C : B { int& operator()() = delete; };
> +using CC = const C;
> +
> +SA( ! __is_invocable( C ) );
> +SA( ! __is_invocable( C& ) );
> +SA( ! __is_invocable( C&& ) );
> +SA( ! __is_invocable( C* ) );
> +SA( ! __is_invocable( CC ) );
> +SA( ! __is_invocable( CC& ) );
> +SA( ! __is_invocable( CC* ) );
> +
> +struct D { B operator*(); };
> +using CD = const D;
> +
> +SA( ! __is_invocable( D ) );
> +
> +struct E { void v(); };
> +using CE = const E;
> +
> +SA( ! __is_invocable( E ) );
> +SA( ! __is_invocable( void (E::*)() ) );
> +SA( __is_invocable( void (E::*)(), E ) );
> +SA( __is_invocable( void (E::*)(), E* ) );
> +SA( ! __is_invocable( void (E::*)(), CE ) );
> +
> +struct F : E {};
> +using CF = const F;
> +
> +SA( ! __is_invocable( F ) );
> +SA( __is_invocable( void (E::*)(), F ) );
> +SA( __is_invocable( void (E::*)(), F* ) );
> +SA( ! __is_invocable( void (E::*)(), CF ) );
> +
> +struct G { E operator*(); };
> +using CG = const G;
> +
> +SA( ! __is_invocable( G ) );
> +SA( __is_invocable( void (E::*)(), G ) );
> +SA( ! __is_invocable( void (E::*)(), G* ) );
> +SA( ! __is_invocable( void (E::*)(), CG ) );
> +
> +struct H { E& operator*(); };
> +using CH = const H;
> +
> +SA( ! __is_invocable( H ) );
> +SA( __is_invocable( void (E::*)(), H ) );
> +SA( ! __is_invocable( void (E::*)(), H* ) );
> +SA( ! __is_invocable( void (E::*)(), CH ) );
> +
> +struct I { E&& operator*(); };
> +using CI = const I;
> +
> +SA( ! __is_invocable( I ) );
> +SA( __is_invocable( void (E::*)(), I ) );
> +SA( ! __is_invocable( void (E::*)(), I* ) );
> +SA( ! __is_invocable( void (E::*)(), CI ) );
> +
> +struct K { E* operator*(); };
> +using CK = const K;
> +
> +SA( ! __is_invocable( K ) );
> +SA( ! __is_invocable( void (E::*)(), K ) );
> +SA( ! __is_invocable( void (E::*)(), K* ) );
> +SA( ! __is_invocable( void (E::*)(), CK ) );
> +
> +struct L { CE operator*(); };
> +using CL = const L;
> +
> +SA( ! __is_invocable( L ) );
> +SA( ! __is_invocable( void (E::*)(), L ) );
> +SA( ! __is_invocable( void (E::*)(), L* ) );
> +SA( ! __is_invocable( void (E::*)(), CL ) );
> +
> +struct M {
> + int i;
> +private:
> + long l;
> +};
> +using CM = const M;
> +
> +SA( ! __is_invocable( M ) );
> +SA( ! __is_invocable( M& ) );
> +SA( ! __is_invocable( M&& ) );
> +SA( ! __is_invocable( M* ) );
> +SA( ! __is_invocable( CM ) );
> +SA( ! __is_invocable( CM& ) );
> +SA( ! __is_invocable( CM* ) );
> +
> +SA( ! __is_invocable( int M::* ) );
> +SA( __is_invocable( int M::*, M ) );
> +SA( __is_invocable( int M::*, M& ) );
> +SA( __is_invocable( int M::*, M&& ) );
> +SA( __is_invocable( int M::*, M* ) );
> +SA( __is_invocable( int M::*, CM ) );
> +SA( __is_invocable( int M::*, CM& ) );
> +SA( __is_invocable( int M::*, CM* ) );
> +SA( ! __is_invocable( int M::*, int ) );
> +
> +SA( ! __is_invocable( int CM::* ) );
> +SA( __is_invocable( int CM::*, M ) );
> +SA( __is_invocable( int CM::*, M& ) );
> +SA( __is_invocable( int CM::*, M&& ) );
> +SA( __is_invocable( int CM::*, M* ) );
> +SA( __is_invocable( int CM::*, CM ) );
> +SA( __is_invocable( int CM::*, CM& ) );
> +SA( __is_invocable( int CM::*, CM* ) );
> +SA( ! __is_invocable( int CM::*, int ) );
> +
> +SA( ! __is_invocable( long M::* ) );
> +SA( __is_invocable( long M::*, M ) );
> +SA( __is_invocable( long M::*, M& ) );
> +SA( __is_invocable( long M::*, M&& ) );
> +SA( __is_invocable( long M::*, M* ) );
> +SA( __is_invocable( long M::*, CM ) );
> +SA( __is_invocable( long M::*, CM& ) );
> +SA( __is_invocable( long M::*, CM* ) );
> +SA( ! __is_invocable( long M::*, long ) );
> +
> +SA( ! __is_invocable( long CM::* ) );
> +SA( __is_invocable( long CM::*, M ) );
> +SA( __is_invocable( long CM::*, M& ) );
> +SA( __is_invocable( long CM::*, M&& ) );
> +SA( __is_invocable( long CM::*, M* ) );
> +SA( __is_invocable( long CM::*, CM ) );
> +SA( __is_invocable( long CM::*, CM& ) );
> +SA( __is_invocable( long CM::*, CM* ) );
> +SA( ! __is_invocable( long CM::*, long ) );
> +
> +SA( ! __is_invocable( short M::* ) );
> +SA( __is_invocable( short M::*, M ) );
> +SA( __is_invocable( short M::*, M& ) );
> +SA( __is_invocable( short M::*, M&& ) );
> +SA( __is_invocable( short M::*, M* ) );
> +SA( __is_invocable( short M::*, CM ) );
> +SA( __is_invocable( short M::*, CM& ) );
> +SA( __is_invocable( short M::*, CM* ) );
> +SA( ! __is_invocable( short M::*, short ) );
> +
> +SA( ! __is_invocable( short CM::* ) );
> +SA( __is_invocable( short CM::*, M ) );
> +SA( __is_invocable( short CM::*, M& ) );
> +SA( __is_invocable( short CM::*, M&& ) );
> +SA( __is_invocable( short CM::*, M* ) );
> +SA( __is_invocable( short CM::*, CM ) );
> +SA( __is_invocable( short CM::*, CM& ) );
> +SA( __is_invocable( short CM::*, CM* ) );
> +SA( ! __is_invocable( short CM::*, short ) );
> +
> +struct N { M operator*(); };
> +SA( __is_invocable( int M::*, N ) );
> +SA( ! __is_invocable( int M::*, N* ) );
> +
> +struct O { M& operator*(); };
> +SA( __is_invocable( int M::*, O ) );
> +SA( ! __is_invocable( int M::*, O* ) );
> +
> +struct P { M&& operator*(); };
> +SA( __is_invocable( int M::*, P ) );
> +SA( ! __is_invocable( int M::*, P* ) );
> +
> +struct Q { M* operator*(); };
> +SA( ! __is_invocable( int M::*, Q ) );
> +SA( ! __is_invocable( int M::*, Q* ) );
> +
> +struct R { void operator()(int = 0); };
> +
> +SA( __is_invocable( R ) );
> +SA( __is_invocable( R, int ) );
> +SA( ! __is_invocable( R, int, int ) );
> +
> +struct S { void operator()(int, ...); };
> +
> +SA( ! __is_invocable( S ) );
> +SA( __is_invocable( S, int ) );
> +SA( __is_invocable( S, int, int ) );
> +SA( __is_invocable( S, int, int, int ) );
> +
> +void fn1() {}
> +
> +SA( __is_invocable( decltype(fn1) ) );
> +
> +void fn2(int arr[10]);
> +
> +SA( __is_invocable( decltype(fn2), int[10] ) );
> +SA( __is_invocable( decltype(fn2), int(&)[10] ) );
> +SA( __is_invocable( decltype(fn2), int(&&)[10] ) );
> +SA( ! __is_invocable( decltype(fn2), int(*)[10] ) );
> +SA( ! __is_invocable( decltype(fn2), int(*&)[10] ) );
> +SA( ! __is_invocable( decltype(fn2), int(*&&)[10] ) );
> +SA( __is_invocable( decltype(fn2), int[] ) );
> +
> +auto lambda = []() {};
> +
> +SA( __is_invocable( decltype(lambda) ) );
> +
> +template <typename Func, typename... Args>
> +struct can_invoke {
> + static constexpr bool value = __is_invocable( Func, Args... );
> +};
> +
> +SA( can_invoke<decltype(lambda)>::value );
> +
> +struct T {
> + void func() const {}
> + int data;
> +};
> +
> +SA( __is_invocable( decltype(&T::func)&, T& ) );
> +SA( __is_invocable( decltype(&T::data)&, T& ) );
> diff --git a/gcc/testsuite/g++.dg/ext/is_invocable2.C b/gcc/testsuite/g++.dg/ext/is_invocable2.C
> new file mode 100644
> index 00000000000..a68aefd3e13
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/is_invocable2.C
> @@ -0,0 +1,139 @@
> +// { dg-do compile { target c++11 } }
> +// __is_invocable should handle std::reference_wrapper correctly.
> +
> +#include <functional>
> +
> +#define SA(X) static_assert((X),#X)
> +
> +using std::reference_wrapper;
> +
> +using func_type_v0 = void(*)();
> +
> +SA( __is_invocable( reference_wrapper<func_type_v0> ) );
> +SA( ! __is_invocable( reference_wrapper<func_type_v0>, int ) );
> +
> +using func_type_i0 = int(*)();
> +
> +SA( __is_invocable( reference_wrapper<func_type_i0> ) );
> +SA( ! __is_invocable( reference_wrapper<func_type_i0>, int ) );
> +
> +using func_type_l0 = int&(*)();
> +
> +SA( __is_invocable( reference_wrapper<func_type_l0> ) );
> +SA( ! __is_invocable( reference_wrapper<func_type_l0(int)> ) );
> +
> +using func_type_ii = int(*)(int);
> +
> +SA( ! __is_invocable( reference_wrapper<func_type_ii> ) );
> +SA( __is_invocable( reference_wrapper<func_type_ii>, int ) );
> +
> +using func_type_il = int(*)(int&);
> +
> +SA( ! __is_invocable( reference_wrapper<func_type_il> ) );
> +SA( ! __is_invocable( reference_wrapper<func_type_il>, int ) );
> +SA( __is_invocable( reference_wrapper<func_type_il>, int& ) );
> +
> +using func_type_ir = int(*)(int&&);
> +
> +SA( ! __is_invocable( reference_wrapper<func_type_ir> ) );
> +SA( ! __is_invocable( reference_wrapper<func_type_ir>, int& ) );
> +SA( __is_invocable( reference_wrapper<func_type_ir>, int ) );
> +SA( __is_invocable( reference_wrapper<func_type_ir>, int&& ) );
> +
> +struct A { };
> +
> +using mem_type_i = int A::*;
> +
> +SA( ! __is_invocable( reference_wrapper<mem_type_i> ) );
> +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int ) );
> +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int* ) );
> +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int& ) );
> +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int&& ) );
> +SA( __is_invocable( reference_wrapper<mem_type_i>, A ) );
> +SA( __is_invocable( reference_wrapper<mem_type_i>, A* ) );
> +SA( __is_invocable( reference_wrapper<mem_type_i>, A& ) );
> +SA( __is_invocable( reference_wrapper<mem_type_i>, A&& ) );
> +
> +using memfun_type_i = int (A::*)();
> +
> +SA( ! __is_invocable( reference_wrapper<memfun_type_i> ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int* ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int& ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int&& ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_i>, A ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_i>, A* ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_i>, A& ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_i>, A&& ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, const A& ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, A&, int ) );
> +
> +using memfun_type_ic = int (A::*)() const;
> +
> +SA( ! __is_invocable( reference_wrapper<memfun_type_ic> ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, int ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, int& ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_ic>, A& ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_ic>, A* ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, A&, int ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, A*, int& ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_ic>, const A& ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_ic>, const A* ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, const A&, int& ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, const A*, int ) );
> +
> +using memfun_type_iic = int& (A::*)(int&) const;
> +
> +SA( ! __is_invocable( reference_wrapper<memfun_type_iic> ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, int ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, int& ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, A&, int ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_iic>, A&, int& ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, A*, int ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_iic>, A*, int& ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int ) );
> +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int&, int ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int& ) );
> +SA( __is_invocable( reference_wrapper<memfun_type_iic>, const A*, int& ) );
> +
> +struct B {
> + int& operator()();
> + long& operator()() const;
> + bool& operator()(int);
> +private:
> + void operator()(int, int);
> +};
> +using CB = const B;
> +
> +SA( __is_invocable( reference_wrapper<B> ) );
> +SA( __is_invocable( reference_wrapper<B>& ) );
> +SA( __is_invocable( reference_wrapper<B>&& ) );
> +SA( __is_invocable( reference_wrapper<CB> ) );
> +SA( __is_invocable( reference_wrapper<CB>& ) );
> +SA( __is_invocable( reference_wrapper<B>, int ) );
> +SA( ! __is_invocable( reference_wrapper<B>&, int, int ) );
> +
> +struct C : B { int& operator()() = delete; };
> +using CC = const C;
> +
> +SA( ! __is_invocable( reference_wrapper<C> ) );
> +SA( ! __is_invocable( reference_wrapper<C>& ) );
> +SA( ! __is_invocable( reference_wrapper<C>&& ) );
> +SA( ! __is_invocable( reference_wrapper<CC> ) );
> +SA( ! __is_invocable( reference_wrapper<CC>& ) );
> +
> +struct D { B operator*(); };
> +using CD = const D;
> +
> +SA( ! __is_invocable( reference_wrapper<D> ) );
> +SA( ! __is_invocable( reference_wrapper<D>& ) );
> +SA( ! __is_invocable( reference_wrapper<D>&& ) );
> +SA( ! __is_invocable( reference_wrapper<D>* ) );
> +SA( ! __is_invocable( reference_wrapper<D*> ) );
> +SA( ! __is_invocable( reference_wrapper<D*>* ) );
> +
> +std::function<void()> fn = []() {};
> +auto refwrap = std::ref(fn);
> +
> +SA( __is_invocable( decltype(fn) ) );
> +SA( __is_invocable( decltype(refwrap) ) );
> diff --git a/gcc/testsuite/g++.dg/ext/is_invocable3.C b/gcc/testsuite/g++.dg/ext/is_invocable3.C
> new file mode 100644
> index 00000000000..e2b0c5ef406
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/is_invocable3.C
> @@ -0,0 +1,51 @@
> +// { dg-do compile { target c++11 } }
> +// __is_invocable should handle incomplete class correctly.
> +
> +#define SA(X) static_assert((X),#X)
> +
> +struct Incomplete;
> +
> +SA( ! __is_invocable( Incomplete ) ); // { dg-error "incomplete type" }
> +SA( ! __is_invocable( Incomplete, int ) ); // { dg-error "incomplete type" }
> +
> +SA( ! __is_invocable( int, Incomplete, int ) ); // { dg-error "incomplete type" }
> +SA( ! __is_invocable( int, Incomplete ) ); // { dg-error "incomplete type" }
> +
> +SA( ! __is_invocable( Incomplete, Incomplete() ) ); // { dg-error "incomplete type" }
> +SA( ! __is_invocable( Incomplete, Incomplete(int), int ) ); // { dg-error "incomplete type" }
> +SA( ! __is_invocable( Incomplete, Incomplete(int, int), int, int ) ); // { dg-error "incomplete type" }
> +
> +SA( ! __is_invocable( Incomplete, Incomplete(), int, int ) ); // { dg-error "incomplete type" }
> +
> +SA( ! __is_invocable( int(Incomplete), Incomplete ) ); // { dg-error "incomplete type" }
> +SA( ! __is_invocable( int(int, Incomplete), int, Incomplete ) ); // { dg-error "incomplete type" }
> +SA( ! __is_invocable( int(int, Incomplete), Incomplete, int ) ); // { dg-error "incomplete type" }
> +
> +SA( __is_invocable( int(Incomplete&), Incomplete& ) ); // { dg-bogus "incomplete type" }
> +SA( __is_invocable( int(int, Incomplete&), int, Incomplete& ) ); // { dg-bogus "incomplete type" }
> +
> +SA( __is_invocable( int(Incomplete&&), Incomplete&& ) ); // { dg-bogus "incomplete type" }
> +SA( __is_invocable( int(int, Incomplete&&), int, Incomplete&& ) ); // { dg-bogus "incomplete type" }
> +
> +SA( __is_invocable( int(const Incomplete&&), const Incomplete&& ) ); // { dg-bogus "incomplete type" }
> +SA( __is_invocable( int(int, const Incomplete&&), int, const Incomplete&& ) ); // { dg-bogus "incomplete type" }
> +
> +SA( __is_invocable( int(const Incomplete&), const Incomplete& ) ); // { dg-bogus "incomplete type" }
> +SA( __is_invocable( int(int, const Incomplete&), int, const Incomplete& ) ); // { dg-bogus "incomplete type" }
> +
> +SA( __is_invocable( int(const Incomplete&), Incomplete& ) ); // { dg-bogus "incomplete type" }
> +SA( __is_invocable( int(int, const Incomplete&), int, Incomplete& ) ); // { dg-bogus "incomplete type" }
> +
> +SA( __is_invocable( int Incomplete::*, const Incomplete& ) ); // { dg-bogus "incomplete type" }
> +SA( ! __is_invocable( void (Incomplete::*)(long&), const Incomplete*, long& ) ); // { dg-bogus "incomplete type" }
> +SA( __is_invocable( void (Incomplete::*)(long&) const, Incomplete*, long& ) ); // { dg-bogus "incomplete type" }
> +
> +template <typename T>
> +struct Holder { T t; };
> +
> +SA( __is_invocable( int(Holder<Incomplete>&), Holder<Incomplete>& ) ); // { dg-bogus "incomplete type" }
> +
> +// Define Incomplete, which is now not incomplete.
> +struct Incomplete { void operator()(); };
> +
> +SA( __is_invocable( Incomplete ) ); // { dg-bogus "incomplete type" }
> diff --git a/gcc/testsuite/g++.dg/ext/is_invocable4.C b/gcc/testsuite/g++.dg/ext/is_invocable4.C
> new file mode 100644
> index 00000000000..d1efccf08f8
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/is_invocable4.C
> @@ -0,0 +1,33 @@
> +// { dg-do compile { target c++11 } }
> +// Failed access check should be a substitution failure, not an error.
> +
> +#define SA(X) static_assert((X),#X)
> +
> +template<bool B>
> +struct bool_constant { static constexpr bool value = B; };
> +
> +template<typename _Fn, typename... _ArgTypes>
> +struct is_invocable
> +: public bool_constant<__is_invocable(_Fn, _ArgTypes...)>
> +{ };
> +
> +#if __cpp_variable_templates
> +template<typename _Fn, typename... _ArgTypes>
> +constexpr bool is_invocable_v = __is_invocable(_Fn, _ArgTypes...);
> +#endif
> +
> +class Private
> +{
> + void operator()() const
> + {
> + SA( ! is_invocable<Private>::value );
> +#if __cpp_variable_templates
> + SA( ! is_invocable_v<Private> );
> +#endif
> + }
> +};
> +
> +SA( ! is_invocable<Private>::value );
> +#if __cpp_variable_templates
> +SA( ! is_invocable_v<Private> );
> +#endif
> --
> 2.42.0
>
>
On Fri, 20 Oct 2023, Patrick Palka wrote:
> On Fri, 20 Oct 2023, Ken Matsui wrote:
>
> > This patch implements built-in trait for std::is_invocable.
>
> Nice! My email client unfortunately ate my first review attempt, so
> apologies for my brevity this time around.
>
> > gcc/cp/ChangeLog:
> >
> > * cp-trait.def: Define __is_invocable.
> > * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_INVOCABLE.
> > * semantics.cc (trait_expr_value): Likewise.
> > (finish_trait_expr): Likewise.
> > (is_invocable_p): New function.
> > * method.h: New file to export build_trait_object in method.cc.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/ext/has-builtin-1.C: Test existence of __is_invocable.
> > * g++.dg/ext/is_invocable1.C: New test.
> > * g++.dg/ext/is_invocable2.C: New test.
> > * g++.dg/ext/is_invocable3.C: New test.
> > * g++.dg/ext/is_invocable4.C: New test.
> >
> > Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> > ---
> > gcc/cp/constraint.cc | 6 +
> > gcc/cp/cp-trait.def | 1 +
> > gcc/cp/method.h | 28 ++
> > gcc/cp/semantics.cc | 135 +++++++++
> > gcc/testsuite/g++.dg/ext/has-builtin-1.C | 3 +
> > gcc/testsuite/g++.dg/ext/is_invocable1.C | 337 +++++++++++++++++++++++
> > gcc/testsuite/g++.dg/ext/is_invocable2.C | 139 ++++++++++
> > gcc/testsuite/g++.dg/ext/is_invocable3.C | 51 ++++
> > gcc/testsuite/g++.dg/ext/is_invocable4.C | 33 +++
> > 9 files changed, 733 insertions(+)
> > create mode 100644 gcc/cp/method.h
> > create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable1.C
> > create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable2.C
> > create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable3.C
> > create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable4.C
> >
> > diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> > index 9fce36e12d1..29bf548d30a 100644
> > --- a/gcc/cp/constraint.cc
> > +++ b/gcc/cp/constraint.cc
> > @@ -3754,6 +3754,12 @@ diagnose_trait_expr (tree expr, tree args)
> > case CPTK_IS_FUNCTION:
> > inform (loc, " %qT is not a function", t1);
> > break;
> > + case CPTK_IS_INVOCABLE:
> > + if (!t2)
> > + inform (loc, " %qT is not invocable", t1);
> > + else
> > + inform (loc, " %qT is not invocable by %qE", t1, t2);
> > + break;
> > case CPTK_IS_LAYOUT_COMPATIBLE:
> > inform (loc, " %qT is not layout compatible with %qT", t1, t2);
> > break;
> > diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> > index 05514a51c21..b8b7608c122 100644
> > --- a/gcc/cp/cp-trait.def
> > +++ b/gcc/cp/cp-trait.def
> > @@ -71,6 +71,7 @@ DEFTRAIT_EXPR (IS_EMPTY, "__is_empty", 1)
> > DEFTRAIT_EXPR (IS_ENUM, "__is_enum", 1)
> > DEFTRAIT_EXPR (IS_FINAL, "__is_final", 1)
> > DEFTRAIT_EXPR (IS_FUNCTION, "__is_function", 1)
> > +DEFTRAIT_EXPR (IS_INVOCABLE, "__is_invocable", -1)
> > DEFTRAIT_EXPR (IS_LAYOUT_COMPATIBLE, "__is_layout_compatible", 2)
> > DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 1)
> > DEFTRAIT_EXPR (IS_MEMBER_FUNCTION_POINTER, "__is_member_function_pointer", 1)
> > diff --git a/gcc/cp/method.h b/gcc/cp/method.h
> > new file mode 100644
> > index 00000000000..1aec8ec5cfd
> > --- /dev/null
> > +++ b/gcc/cp/method.h
> > @@ -0,0 +1,28 @@
> > +/* Functions exported by method.cc.
> > + Copyright (C) 2023 Free Software Foundation, Inc.
> > +
> > +This file is part of GCC.
> > +
> > +GCC is free software; you can redistribute it and/or modify
> > +it under the terms of the GNU General Public License as published by
> > +the Free Software Foundation; either version 3, or (at your option)
> > +any later version.
> > +
> > +GCC is distributed in the hope that it will be useful,
> > +but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > +GNU General Public License for more details.
> > +
> > +You should have received a copy of the GNU General Public License
> > +along with GCC; see the file COPYING3. If not see
> > +<http://www.gnu.org/licenses/>. */
> > +
> > +#ifndef GCC_CP_METHOD_H
> > +#define GCC_CP_METHOD_H 1
> > +
> > +#include "tree.h"
> > +
> > +/* In method.cc */
> > +extern tree build_trait_object (tree type);
>
> Since other method.cc exports are already declared in cp-tree.h, for now
> let's just declare this in cp-tree.h as well (under build_stub_object)
> instead of creating a new header file.
>
> > +
> > +#endif /* GCC_CP_METHOD_H */
> > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> > index 7cccbae5287..cc2e400531a 100644
> > --- a/gcc/cp/semantics.cc
> > +++ b/gcc/cp/semantics.cc
> > @@ -45,6 +45,10 @@ along with GCC; see the file COPYING3. If not see
> > #include "gomp-constants.h"
> > #include "predict.h"
> > #include "memmodel.h"
> > +#include "method.h"
> > +
> > +#include "print-tree.h"
> > +#include "tree-pretty-print.h"
> >
> > /* There routines provide a modular interface to perform many parsing
> > operations. They may therefore be used during actual parsing, or
> > @@ -11714,6 +11718,133 @@ classtype_has_nothrow_assign_or_copy_p (tree type, bool assign_p)
> > return saw_copy;
> > }
> >
> > +/* Return true if FN_TYPE is invocable with the given ARG_TYPES. */
> > +
> > +static bool
> > +is_invocable_p (tree fn_type, tree arg_types)
> > +{
> > + /* ARG_TYPES must be a TREE_VEC. */
> > + gcc_assert (TREE_CODE (arg_types) == TREE_VEC);
> > +
> > + /* Access check is required to determine if the given is invocable. */
> > + deferring_access_check_sentinel acs (dk_no_deferred);
> > +
> > + /* std::is_invocable is an unevaluated context. */
> > + cp_unevaluated cp_uneval_guard;
> > +
> > + bool is_ptrdatamem;
> > + bool is_ptrmemfunc;
> > + if (TREE_CODE (fn_type) == REFERENCE_TYPE)
> > + {
> > + tree deref_fn_type = TREE_TYPE (fn_type);
> > + is_ptrdatamem = TYPE_PTRDATAMEM_P (deref_fn_type);
> > + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (deref_fn_type);
> > +
> > + /* Dereference fn_type if it is a pointer to member. */
> > + if (is_ptrdatamem || is_ptrmemfunc)
> > + fn_type = deref_fn_type;
> > + }
> > + else
> > + {
> > + is_ptrdatamem = TYPE_PTRDATAMEM_P (fn_type);
> > + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (fn_type);
> > + }
> > +
> > + if (is_ptrdatamem && TREE_VEC_LENGTH (arg_types) != 1)
> > + /* A pointer to data member with non-one argument is not invocable. */
> > + return false;
> > +
> > + if (is_ptrmemfunc && TREE_VEC_LENGTH (arg_types) == 0)
> > + /* A pointer to member function with no arguments is not invocable. */
> > + return false;
> > +
> > + /* Construct an expression of a pointer to member. */
> > + tree datum;
> > + if (is_ptrdatamem || is_ptrmemfunc)
> > + {
> > + tree datum_type = TREE_VEC_ELT (arg_types, 0);
> > +
> > + /* Dereference datum. */
> > + if (CLASS_TYPE_P (datum_type))
> > + {
> > + bool is_refwrap = false;
> > +
> > + tree datum_decl = TYPE_NAME (TYPE_MAIN_VARIANT (datum_type));
> > + if (decl_in_std_namespace_p (datum_decl))
> > + {
> > + tree name = DECL_NAME (datum_decl);
> > + if (name && (id_equal (name, "reference_wrapper")))
> > + {
> > + /* Handle std::reference_wrapper. */
> > + is_refwrap = true;
> > + datum_type = cp_build_reference_type (datum_type, false);
> > + }
> > + }
> > +
> > + datum = build_trait_object (datum_type);
> > +
> > + /* If datum_type was not std::reference_wrapper, check if it has
> > + operator*() overload. If datum_type was std::reference_wrapper,
> > + avoid dereferencing the datum twice. */
> > + if (!is_refwrap)
> > + if (get_class_binding (datum_type, get_identifier ("operator*")))
>
> We probably should use lookup_member instead of get_class_binding since
> IIUC the latter doesn't look into bases:
>
> struct A { int m; };
> struct B { A& operator*(): };
> struct C : B { };
> static_assert(std::is_invocable_v<int A::*, C>);
>
> However, I notice that the specification of INVOKE
> (https://eel.is/c++draft/func.require#lib:INVOKE) doesn't mention name
> lookup at all so it strikes me as suspicious that we'd perform name
> lookup here. I think this would misbehave for:
>
> struct A { };
> struct B : A { A& operator*() = delete; };
> static_assert(std::is_invocable_v<int A::*, B>);
>
> struct C : private A { A& operator*(); };
> static_assert(std::is_invocable_v<int A::*, C>);
Oops, this static_assert is missing a !
>
> ultimately because we end up choosing the dereference form of INVOKE,
> but according to 1.1/1.4 we should choose the non-dereference form?
>
> > + /* Handle operator*(). */
> > + datum = build_x_indirect_ref (UNKNOWN_LOCATION, datum,
> > + RO_UNARY_STAR, NULL_TREE,
> > + tf_none);
> > + }
> > + else if (POINTER_TYPE_P (datum_type))
> > + datum = build_trait_object (TREE_TYPE (datum_type));
> > + else
> > + datum = build_trait_object (datum_type);
> > + }
> > +
> > + /* Build a function expression. */
> > + tree fn;
> > + if (is_ptrdatamem)
> > + fn = build_m_component_ref (datum, build_trait_object (fn_type), tf_none);
>
> Maybe exit early for the is_ptrdatamem case here (and simplify the rest
> of the function accordingly)?
>
> > + else if (is_ptrmemfunc)
> > + fn = build_trait_object (TYPE_PTRMEMFUNC_FN_TYPE (fn_type));
> > + else
> > + fn = build_trait_object (fn_type);
> > +
> > + /* Construct arguments to the function and an expression of a call. */
> > + if (!is_ptrdatamem)
> > + {
> > + releasing_vec args;
> > +
> > + if (is_ptrmemfunc)
> > + {
> > + /* A pointer to member function is internally converted to a pointer
> > + to function that takes a pointer to the dereferenced datum type
> > + as its first argument and original arguments afterward. If the
> > + function is a const member function, the first argument also
> > + requires a const datum pointer and vice-versa. */
> > +
> > + tree datum_type = TREE_TYPE (datum);
> > + if (TYPE_REF_P (datum_type))
> > + datum_type = TREE_TYPE (datum_type);
> > +
> > + datum = build_trait_object (build_pointer_type (datum_type));
> > + vec_safe_push (args, datum);
> > + }
> > +
> > + for (int i = is_ptrmemfunc ? 1 : 0; i < TREE_VEC_LENGTH (arg_types); ++i)
> > + {
> > + tree arg_type = TREE_VEC_ELT (arg_types, i);
> > + tree arg = build_trait_object (arg_type);
> > + vec_safe_push (args, arg);
> > + }
> > +
> > + fn = finish_call_expr (fn, &args, false, false, tf_none);
> > + }
> > +
> > + if (error_operand_p (fn))
> > + return false;
> > +
> > + return true;
> > +}
> > +
> > /* Return true if DERIVED is pointer interconvertible base of BASE. */
> >
> > static bool
> > @@ -12181,6 +12312,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> > case CPTK_IS_FUNCTION:
> > return type_code1 == FUNCTION_TYPE;
> >
> > + case CPTK_IS_INVOCABLE:
> > + return is_invocable_p (type1, type2);
> > +
> > case CPTK_IS_LAYOUT_COMPATIBLE:
> > return layout_compatible_type_p (type1, type2);
> >
> > @@ -12390,6 +12524,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
> > break;
> >
> > case CPTK_IS_CONVERTIBLE:
> > + case CPTK_IS_INVOCABLE:
> > case CPTK_IS_NOTHROW_ASSIGNABLE:
> > case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > case CPTK_IS_NOTHROW_CONVERTIBLE:
> > diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > index b1430e9bd8b..3a9bda1ee03 100644
> > --- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > +++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > @@ -92,6 +92,9 @@
> > #if !__has_builtin (__is_function)
> > # error "__has_builtin (__is_function) failed"
> > #endif
> > +#if !__has_builtin (__is_invocable)
> > +# error "__has_builtin (__is_invocable) failed"
> > +#endif
> > #if !__has_builtin (__is_layout_compatible)
> > # error "__has_builtin (__is_layout_compatible) failed"
> > #endif
> > diff --git a/gcc/testsuite/g++.dg/ext/is_invocable1.C b/gcc/testsuite/g++.dg/ext/is_invocable1.C
> > new file mode 100644
> > index 00000000000..2fd3906b571
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/is_invocable1.C
> > @@ -0,0 +1,337 @@
> > +// { dg-do compile { target c++11 } }
> > +
> > +#define SA(X) static_assert((X),#X)
> > +
> > +using func_type_v0 = void(*)();
> > +
> > +SA( __is_invocable( func_type_v0 ) );
> > +SA( ! __is_invocable( func_type_v0, int ) );
> > +
> > +using func_type_i0 = int(*)();
> > +
> > +SA( __is_invocable( func_type_i0 ) );
> > +SA( ! __is_invocable( func_type_i0, int ) );
> > +
> > +using func_type_l0 = int&(*)();
> > +
> > +SA( __is_invocable( func_type_l0 ) );
> > +SA( ! __is_invocable( func_type_l0(int) ) );
> > +
> > +using func_type_ii = int(*)(int);
> > +
> > +SA( ! __is_invocable( func_type_ii ) );
> > +SA( __is_invocable( func_type_ii, int ) );
> > +
> > +using func_type_il = int(*)(int&);
> > +
> > +SA( ! __is_invocable( func_type_il ) );
> > +SA( ! __is_invocable( func_type_il, int ) );
> > +SA( __is_invocable( func_type_il, int& ) );
> > +
> > +using func_type_ir = int(*)(int&&);
> > +
> > +SA( ! __is_invocable( func_type_ir ) );
> > +SA( ! __is_invocable( func_type_ir, int& ) );
> > +SA( __is_invocable( func_type_ir, int ) );
> > +SA( __is_invocable( func_type_ir, int&& ) );
> > +
> > +struct A { };
> > +
> > +using mem_type_i = int A::*;
> > +
> > +SA( ! __is_invocable( mem_type_i ) );
> > +SA( ! __is_invocable( mem_type_i, int ) );
> > +SA( ! __is_invocable( mem_type_i, int* ) );
> > +SA( ! __is_invocable( mem_type_i, int& ) );
> > +SA( ! __is_invocable( mem_type_i, int&& ) );
> > +SA( __is_invocable( mem_type_i, A ) );
> > +SA( __is_invocable( mem_type_i, A* ) );
> > +SA( __is_invocable( mem_type_i, A& ) );
> > +SA( __is_invocable( mem_type_i, A&& ) );
> > +SA( __is_invocable( mem_type_i, const A& ) );
> > +SA( ! __is_invocable( mem_type_i, A&, int ) );
> > +
> > +using memfun_type_i = int (A::*)();
> > +
> > +SA( ! __is_invocable( memfun_type_i ) );
> > +SA( ! __is_invocable( memfun_type_i, int ) );
> > +SA( ! __is_invocable( memfun_type_i, int* ) );
> > +SA( ! __is_invocable( memfun_type_i, int& ) );
> > +SA( ! __is_invocable( memfun_type_i, int&& ) );
> > +SA( __is_invocable( memfun_type_i, A ) );
> > +SA( __is_invocable( memfun_type_i, A* ) );
> > +SA( __is_invocable( memfun_type_i, A& ) );
> > +SA( __is_invocable( memfun_type_i, A&& ) );
> > +SA( ! __is_invocable( memfun_type_i, const A& ) );
> > +SA( ! __is_invocable( memfun_type_i, A&, int ) );
> > +
> > +using memfun_type_ic = int (A::*)() const;
> > +
> > +SA( ! __is_invocable( memfun_type_ic ) );
> > +SA( ! __is_invocable( memfun_type_ic, int ) );
> > +SA( ! __is_invocable( memfun_type_ic, int& ) );
> > +SA( __is_invocable( memfun_type_ic, A& ) );
> > +SA( __is_invocable( memfun_type_ic, A* ) );
> > +SA( ! __is_invocable( memfun_type_ic, A&, int ) );
> > +SA( ! __is_invocable( memfun_type_ic, A*, int& ) );
> > +SA( __is_invocable( memfun_type_ic, const A& ) );
> > +SA( __is_invocable( memfun_type_ic, const A* ) );
> > +SA( ! __is_invocable( memfun_type_ic, const A&, int& ) );
> > +SA( ! __is_invocable( memfun_type_ic, const A*, int ) );
> > +
> > +using memfun_type_iic = int& (A::*)(int&) const;
> > +
> > +SA( ! __is_invocable( memfun_type_iic ) );
> > +SA( ! __is_invocable( memfun_type_iic, int ) );
> > +SA( ! __is_invocable( memfun_type_iic, int& ) );
> > +SA( ! __is_invocable( memfun_type_iic, A&, int ) );
> > +SA( __is_invocable( memfun_type_iic, A&, int& ) );
> > +SA( ! __is_invocable( memfun_type_iic, A*, int ) );
> > +SA( __is_invocable( memfun_type_iic, A*, int& ) );
> > +SA( ! __is_invocable( memfun_type_iic, const A&, int ) );
> > +SA( ! __is_invocable( memfun_type_iic, const A&, int&, int ) );
> > +SA( __is_invocable( memfun_type_iic, const A&, int& ) );
> > +SA( __is_invocable( memfun_type_iic, const A*, int& ) );
> > +
> > +struct B {
> > + int& operator()();
> > + long& operator()() const;
> > + bool& operator()(int);
> > +private:
> > + void operator()(int, int);
> > +};
> > +using CB = const B;
> > +
> > +SA( __is_invocable( B ) );
> > +SA( __is_invocable( B& ) );
> > +SA( __is_invocable( B&& ) );
> > +SA( ! __is_invocable( B* ) );
> > +SA( __is_invocable( CB ) );
> > +SA( __is_invocable( CB& ) );
> > +SA( ! __is_invocable( CB* ) );
> > +
> > +SA( __is_invocable( B, int ) );
> > +SA( __is_invocable( B&, int ) );
> > +SA( __is_invocable( B&&, int ) );
> > +SA( ! __is_invocable( B*, int ) );
> > +SA( ! __is_invocable( CB, int ) );
> > +SA( ! __is_invocable( CB&, int ) );
> > +SA( ! __is_invocable( CB*, int ) );
> > +
> > +SA( ! __is_invocable( B, int, int ) );
> > +SA( ! __is_invocable( B&, int, int ) );
> > +SA( ! __is_invocable( B&&, int, int ) );
> > +SA( ! __is_invocable( B*, int, int ) );
> > +SA( ! __is_invocable( CB, int, int ) );
> > +SA( ! __is_invocable( CB&, int, int ) );
> > +SA( ! __is_invocable( CB*, int, int ) );
> > +
> > +struct C : B { int& operator()() = delete; };
> > +using CC = const C;
> > +
> > +SA( ! __is_invocable( C ) );
> > +SA( ! __is_invocable( C& ) );
> > +SA( ! __is_invocable( C&& ) );
> > +SA( ! __is_invocable( C* ) );
> > +SA( ! __is_invocable( CC ) );
> > +SA( ! __is_invocable( CC& ) );
> > +SA( ! __is_invocable( CC* ) );
> > +
> > +struct D { B operator*(); };
> > +using CD = const D;
> > +
> > +SA( ! __is_invocable( D ) );
> > +
> > +struct E { void v(); };
> > +using CE = const E;
> > +
> > +SA( ! __is_invocable( E ) );
> > +SA( ! __is_invocable( void (E::*)() ) );
> > +SA( __is_invocable( void (E::*)(), E ) );
> > +SA( __is_invocable( void (E::*)(), E* ) );
> > +SA( ! __is_invocable( void (E::*)(), CE ) );
> > +
> > +struct F : E {};
> > +using CF = const F;
> > +
> > +SA( ! __is_invocable( F ) );
> > +SA( __is_invocable( void (E::*)(), F ) );
> > +SA( __is_invocable( void (E::*)(), F* ) );
> > +SA( ! __is_invocable( void (E::*)(), CF ) );
> > +
> > +struct G { E operator*(); };
> > +using CG = const G;
> > +
> > +SA( ! __is_invocable( G ) );
> > +SA( __is_invocable( void (E::*)(), G ) );
> > +SA( ! __is_invocable( void (E::*)(), G* ) );
> > +SA( ! __is_invocable( void (E::*)(), CG ) );
> > +
> > +struct H { E& operator*(); };
> > +using CH = const H;
> > +
> > +SA( ! __is_invocable( H ) );
> > +SA( __is_invocable( void (E::*)(), H ) );
> > +SA( ! __is_invocable( void (E::*)(), H* ) );
> > +SA( ! __is_invocable( void (E::*)(), CH ) );
> > +
> > +struct I { E&& operator*(); };
> > +using CI = const I;
> > +
> > +SA( ! __is_invocable( I ) );
> > +SA( __is_invocable( void (E::*)(), I ) );
> > +SA( ! __is_invocable( void (E::*)(), I* ) );
> > +SA( ! __is_invocable( void (E::*)(), CI ) );
> > +
> > +struct K { E* operator*(); };
> > +using CK = const K;
> > +
> > +SA( ! __is_invocable( K ) );
> > +SA( ! __is_invocable( void (E::*)(), K ) );
> > +SA( ! __is_invocable( void (E::*)(), K* ) );
> > +SA( ! __is_invocable( void (E::*)(), CK ) );
> > +
> > +struct L { CE operator*(); };
> > +using CL = const L;
> > +
> > +SA( ! __is_invocable( L ) );
> > +SA( ! __is_invocable( void (E::*)(), L ) );
> > +SA( ! __is_invocable( void (E::*)(), L* ) );
> > +SA( ! __is_invocable( void (E::*)(), CL ) );
> > +
> > +struct M {
> > + int i;
> > +private:
> > + long l;
> > +};
> > +using CM = const M;
> > +
> > +SA( ! __is_invocable( M ) );
> > +SA( ! __is_invocable( M& ) );
> > +SA( ! __is_invocable( M&& ) );
> > +SA( ! __is_invocable( M* ) );
> > +SA( ! __is_invocable( CM ) );
> > +SA( ! __is_invocable( CM& ) );
> > +SA( ! __is_invocable( CM* ) );
> > +
> > +SA( ! __is_invocable( int M::* ) );
> > +SA( __is_invocable( int M::*, M ) );
> > +SA( __is_invocable( int M::*, M& ) );
> > +SA( __is_invocable( int M::*, M&& ) );
> > +SA( __is_invocable( int M::*, M* ) );
> > +SA( __is_invocable( int M::*, CM ) );
> > +SA( __is_invocable( int M::*, CM& ) );
> > +SA( __is_invocable( int M::*, CM* ) );
> > +SA( ! __is_invocable( int M::*, int ) );
> > +
> > +SA( ! __is_invocable( int CM::* ) );
> > +SA( __is_invocable( int CM::*, M ) );
> > +SA( __is_invocable( int CM::*, M& ) );
> > +SA( __is_invocable( int CM::*, M&& ) );
> > +SA( __is_invocable( int CM::*, M* ) );
> > +SA( __is_invocable( int CM::*, CM ) );
> > +SA( __is_invocable( int CM::*, CM& ) );
> > +SA( __is_invocable( int CM::*, CM* ) );
> > +SA( ! __is_invocable( int CM::*, int ) );
> > +
> > +SA( ! __is_invocable( long M::* ) );
> > +SA( __is_invocable( long M::*, M ) );
> > +SA( __is_invocable( long M::*, M& ) );
> > +SA( __is_invocable( long M::*, M&& ) );
> > +SA( __is_invocable( long M::*, M* ) );
> > +SA( __is_invocable( long M::*, CM ) );
> > +SA( __is_invocable( long M::*, CM& ) );
> > +SA( __is_invocable( long M::*, CM* ) );
> > +SA( ! __is_invocable( long M::*, long ) );
> > +
> > +SA( ! __is_invocable( long CM::* ) );
> > +SA( __is_invocable( long CM::*, M ) );
> > +SA( __is_invocable( long CM::*, M& ) );
> > +SA( __is_invocable( long CM::*, M&& ) );
> > +SA( __is_invocable( long CM::*, M* ) );
> > +SA( __is_invocable( long CM::*, CM ) );
> > +SA( __is_invocable( long CM::*, CM& ) );
> > +SA( __is_invocable( long CM::*, CM* ) );
> > +SA( ! __is_invocable( long CM::*, long ) );
> > +
> > +SA( ! __is_invocable( short M::* ) );
> > +SA( __is_invocable( short M::*, M ) );
> > +SA( __is_invocable( short M::*, M& ) );
> > +SA( __is_invocable( short M::*, M&& ) );
> > +SA( __is_invocable( short M::*, M* ) );
> > +SA( __is_invocable( short M::*, CM ) );
> > +SA( __is_invocable( short M::*, CM& ) );
> > +SA( __is_invocable( short M::*, CM* ) );
> > +SA( ! __is_invocable( short M::*, short ) );
> > +
> > +SA( ! __is_invocable( short CM::* ) );
> > +SA( __is_invocable( short CM::*, M ) );
> > +SA( __is_invocable( short CM::*, M& ) );
> > +SA( __is_invocable( short CM::*, M&& ) );
> > +SA( __is_invocable( short CM::*, M* ) );
> > +SA( __is_invocable( short CM::*, CM ) );
> > +SA( __is_invocable( short CM::*, CM& ) );
> > +SA( __is_invocable( short CM::*, CM* ) );
> > +SA( ! __is_invocable( short CM::*, short ) );
> > +
> > +struct N { M operator*(); };
> > +SA( __is_invocable( int M::*, N ) );
> > +SA( ! __is_invocable( int M::*, N* ) );
> > +
> > +struct O { M& operator*(); };
> > +SA( __is_invocable( int M::*, O ) );
> > +SA( ! __is_invocable( int M::*, O* ) );
> > +
> > +struct P { M&& operator*(); };
> > +SA( __is_invocable( int M::*, P ) );
> > +SA( ! __is_invocable( int M::*, P* ) );
> > +
> > +struct Q { M* operator*(); };
> > +SA( ! __is_invocable( int M::*, Q ) );
> > +SA( ! __is_invocable( int M::*, Q* ) );
> > +
> > +struct R { void operator()(int = 0); };
> > +
> > +SA( __is_invocable( R ) );
> > +SA( __is_invocable( R, int ) );
> > +SA( ! __is_invocable( R, int, int ) );
> > +
> > +struct S { void operator()(int, ...); };
> > +
> > +SA( ! __is_invocable( S ) );
> > +SA( __is_invocable( S, int ) );
> > +SA( __is_invocable( S, int, int ) );
> > +SA( __is_invocable( S, int, int, int ) );
> > +
> > +void fn1() {}
> > +
> > +SA( __is_invocable( decltype(fn1) ) );
> > +
> > +void fn2(int arr[10]);
> > +
> > +SA( __is_invocable( decltype(fn2), int[10] ) );
> > +SA( __is_invocable( decltype(fn2), int(&)[10] ) );
> > +SA( __is_invocable( decltype(fn2), int(&&)[10] ) );
> > +SA( ! __is_invocable( decltype(fn2), int(*)[10] ) );
> > +SA( ! __is_invocable( decltype(fn2), int(*&)[10] ) );
> > +SA( ! __is_invocable( decltype(fn2), int(*&&)[10] ) );
> > +SA( __is_invocable( decltype(fn2), int[] ) );
> > +
> > +auto lambda = []() {};
> > +
> > +SA( __is_invocable( decltype(lambda) ) );
> > +
> > +template <typename Func, typename... Args>
> > +struct can_invoke {
> > + static constexpr bool value = __is_invocable( Func, Args... );
> > +};
> > +
> > +SA( can_invoke<decltype(lambda)>::value );
> > +
> > +struct T {
> > + void func() const {}
> > + int data;
> > +};
> > +
> > +SA( __is_invocable( decltype(&T::func)&, T& ) );
> > +SA( __is_invocable( decltype(&T::data)&, T& ) );
> > diff --git a/gcc/testsuite/g++.dg/ext/is_invocable2.C b/gcc/testsuite/g++.dg/ext/is_invocable2.C
> > new file mode 100644
> > index 00000000000..a68aefd3e13
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/is_invocable2.C
> > @@ -0,0 +1,139 @@
> > +// { dg-do compile { target c++11 } }
> > +// __is_invocable should handle std::reference_wrapper correctly.
> > +
> > +#include <functional>
> > +
> > +#define SA(X) static_assert((X),#X)
> > +
> > +using std::reference_wrapper;
> > +
> > +using func_type_v0 = void(*)();
> > +
> > +SA( __is_invocable( reference_wrapper<func_type_v0> ) );
> > +SA( ! __is_invocable( reference_wrapper<func_type_v0>, int ) );
> > +
> > +using func_type_i0 = int(*)();
> > +
> > +SA( __is_invocable( reference_wrapper<func_type_i0> ) );
> > +SA( ! __is_invocable( reference_wrapper<func_type_i0>, int ) );
> > +
> > +using func_type_l0 = int&(*)();
> > +
> > +SA( __is_invocable( reference_wrapper<func_type_l0> ) );
> > +SA( ! __is_invocable( reference_wrapper<func_type_l0(int)> ) );
> > +
> > +using func_type_ii = int(*)(int);
> > +
> > +SA( ! __is_invocable( reference_wrapper<func_type_ii> ) );
> > +SA( __is_invocable( reference_wrapper<func_type_ii>, int ) );
> > +
> > +using func_type_il = int(*)(int&);
> > +
> > +SA( ! __is_invocable( reference_wrapper<func_type_il> ) );
> > +SA( ! __is_invocable( reference_wrapper<func_type_il>, int ) );
> > +SA( __is_invocable( reference_wrapper<func_type_il>, int& ) );
> > +
> > +using func_type_ir = int(*)(int&&);
> > +
> > +SA( ! __is_invocable( reference_wrapper<func_type_ir> ) );
> > +SA( ! __is_invocable( reference_wrapper<func_type_ir>, int& ) );
> > +SA( __is_invocable( reference_wrapper<func_type_ir>, int ) );
> > +SA( __is_invocable( reference_wrapper<func_type_ir>, int&& ) );
> > +
> > +struct A { };
> > +
> > +using mem_type_i = int A::*;
> > +
> > +SA( ! __is_invocable( reference_wrapper<mem_type_i> ) );
> > +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int ) );
> > +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int* ) );
> > +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int& ) );
> > +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int&& ) );
> > +SA( __is_invocable( reference_wrapper<mem_type_i>, A ) );
> > +SA( __is_invocable( reference_wrapper<mem_type_i>, A* ) );
> > +SA( __is_invocable( reference_wrapper<mem_type_i>, A& ) );
> > +SA( __is_invocable( reference_wrapper<mem_type_i>, A&& ) );
> > +
> > +using memfun_type_i = int (A::*)();
> > +
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_i> ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int* ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int& ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int&& ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_i>, A ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_i>, A* ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_i>, A& ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_i>, A&& ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, const A& ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, A&, int ) );
> > +
> > +using memfun_type_ic = int (A::*)() const;
> > +
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic> ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, int ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, int& ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_ic>, A& ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_ic>, A* ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, A&, int ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, A*, int& ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_ic>, const A& ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_ic>, const A* ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, const A&, int& ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, const A*, int ) );
> > +
> > +using memfun_type_iic = int& (A::*)(int&) const;
> > +
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic> ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, int ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, int& ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, A&, int ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_iic>, A&, int& ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, A*, int ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_iic>, A*, int& ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int ) );
> > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int&, int ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int& ) );
> > +SA( __is_invocable( reference_wrapper<memfun_type_iic>, const A*, int& ) );
> > +
> > +struct B {
> > + int& operator()();
> > + long& operator()() const;
> > + bool& operator()(int);
> > +private:
> > + void operator()(int, int);
> > +};
> > +using CB = const B;
> > +
> > +SA( __is_invocable( reference_wrapper<B> ) );
> > +SA( __is_invocable( reference_wrapper<B>& ) );
> > +SA( __is_invocable( reference_wrapper<B>&& ) );
> > +SA( __is_invocable( reference_wrapper<CB> ) );
> > +SA( __is_invocable( reference_wrapper<CB>& ) );
> > +SA( __is_invocable( reference_wrapper<B>, int ) );
> > +SA( ! __is_invocable( reference_wrapper<B>&, int, int ) );
> > +
> > +struct C : B { int& operator()() = delete; };
> > +using CC = const C;
> > +
> > +SA( ! __is_invocable( reference_wrapper<C> ) );
> > +SA( ! __is_invocable( reference_wrapper<C>& ) );
> > +SA( ! __is_invocable( reference_wrapper<C>&& ) );
> > +SA( ! __is_invocable( reference_wrapper<CC> ) );
> > +SA( ! __is_invocable( reference_wrapper<CC>& ) );
> > +
> > +struct D { B operator*(); };
> > +using CD = const D;
> > +
> > +SA( ! __is_invocable( reference_wrapper<D> ) );
> > +SA( ! __is_invocable( reference_wrapper<D>& ) );
> > +SA( ! __is_invocable( reference_wrapper<D>&& ) );
> > +SA( ! __is_invocable( reference_wrapper<D>* ) );
> > +SA( ! __is_invocable( reference_wrapper<D*> ) );
> > +SA( ! __is_invocable( reference_wrapper<D*>* ) );
> > +
> > +std::function<void()> fn = []() {};
> > +auto refwrap = std::ref(fn);
> > +
> > +SA( __is_invocable( decltype(fn) ) );
> > +SA( __is_invocable( decltype(refwrap) ) );
> > diff --git a/gcc/testsuite/g++.dg/ext/is_invocable3.C b/gcc/testsuite/g++.dg/ext/is_invocable3.C
> > new file mode 100644
> > index 00000000000..e2b0c5ef406
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/is_invocable3.C
> > @@ -0,0 +1,51 @@
> > +// { dg-do compile { target c++11 } }
> > +// __is_invocable should handle incomplete class correctly.
> > +
> > +#define SA(X) static_assert((X),#X)
> > +
> > +struct Incomplete;
> > +
> > +SA( ! __is_invocable( Incomplete ) ); // { dg-error "incomplete type" }
> > +SA( ! __is_invocable( Incomplete, int ) ); // { dg-error "incomplete type" }
> > +
> > +SA( ! __is_invocable( int, Incomplete, int ) ); // { dg-error "incomplete type" }
> > +SA( ! __is_invocable( int, Incomplete ) ); // { dg-error "incomplete type" }
> > +
> > +SA( ! __is_invocable( Incomplete, Incomplete() ) ); // { dg-error "incomplete type" }
> > +SA( ! __is_invocable( Incomplete, Incomplete(int), int ) ); // { dg-error "incomplete type" }
> > +SA( ! __is_invocable( Incomplete, Incomplete(int, int), int, int ) ); // { dg-error "incomplete type" }
> > +
> > +SA( ! __is_invocable( Incomplete, Incomplete(), int, int ) ); // { dg-error "incomplete type" }
> > +
> > +SA( ! __is_invocable( int(Incomplete), Incomplete ) ); // { dg-error "incomplete type" }
> > +SA( ! __is_invocable( int(int, Incomplete), int, Incomplete ) ); // { dg-error "incomplete type" }
> > +SA( ! __is_invocable( int(int, Incomplete), Incomplete, int ) ); // { dg-error "incomplete type" }
> > +
> > +SA( __is_invocable( int(Incomplete&), Incomplete& ) ); // { dg-bogus "incomplete type" }
> > +SA( __is_invocable( int(int, Incomplete&), int, Incomplete& ) ); // { dg-bogus "incomplete type" }
> > +
> > +SA( __is_invocable( int(Incomplete&&), Incomplete&& ) ); // { dg-bogus "incomplete type" }
> > +SA( __is_invocable( int(int, Incomplete&&), int, Incomplete&& ) ); // { dg-bogus "incomplete type" }
> > +
> > +SA( __is_invocable( int(const Incomplete&&), const Incomplete&& ) ); // { dg-bogus "incomplete type" }
> > +SA( __is_invocable( int(int, const Incomplete&&), int, const Incomplete&& ) ); // { dg-bogus "incomplete type" }
> > +
> > +SA( __is_invocable( int(const Incomplete&), const Incomplete& ) ); // { dg-bogus "incomplete type" }
> > +SA( __is_invocable( int(int, const Incomplete&), int, const Incomplete& ) ); // { dg-bogus "incomplete type" }
> > +
> > +SA( __is_invocable( int(const Incomplete&), Incomplete& ) ); // { dg-bogus "incomplete type" }
> > +SA( __is_invocable( int(int, const Incomplete&), int, Incomplete& ) ); // { dg-bogus "incomplete type" }
> > +
> > +SA( __is_invocable( int Incomplete::*, const Incomplete& ) ); // { dg-bogus "incomplete type" }
> > +SA( ! __is_invocable( void (Incomplete::*)(long&), const Incomplete*, long& ) ); // { dg-bogus "incomplete type" }
> > +SA( __is_invocable( void (Incomplete::*)(long&) const, Incomplete*, long& ) ); // { dg-bogus "incomplete type" }
> > +
> > +template <typename T>
> > +struct Holder { T t; };
> > +
> > +SA( __is_invocable( int(Holder<Incomplete>&), Holder<Incomplete>& ) ); // { dg-bogus "incomplete type" }
> > +
> > +// Define Incomplete, which is now not incomplete.
> > +struct Incomplete { void operator()(); };
> > +
> > +SA( __is_invocable( Incomplete ) ); // { dg-bogus "incomplete type" }
> > diff --git a/gcc/testsuite/g++.dg/ext/is_invocable4.C b/gcc/testsuite/g++.dg/ext/is_invocable4.C
> > new file mode 100644
> > index 00000000000..d1efccf08f8
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/is_invocable4.C
> > @@ -0,0 +1,33 @@
> > +// { dg-do compile { target c++11 } }
> > +// Failed access check should be a substitution failure, not an error.
> > +
> > +#define SA(X) static_assert((X),#X)
> > +
> > +template<bool B>
> > +struct bool_constant { static constexpr bool value = B; };
> > +
> > +template<typename _Fn, typename... _ArgTypes>
> > +struct is_invocable
> > +: public bool_constant<__is_invocable(_Fn, _ArgTypes...)>
> > +{ };
> > +
> > +#if __cpp_variable_templates
> > +template<typename _Fn, typename... _ArgTypes>
> > +constexpr bool is_invocable_v = __is_invocable(_Fn, _ArgTypes...);
> > +#endif
> > +
> > +class Private
> > +{
> > + void operator()() const
> > + {
> > + SA( ! is_invocable<Private>::value );
> > +#if __cpp_variable_templates
> > + SA( ! is_invocable_v<Private> );
> > +#endif
> > + }
> > +};
> > +
> > +SA( ! is_invocable<Private>::value );
> > +#if __cpp_variable_templates
> > +SA( ! is_invocable_v<Private> );
> > +#endif
> > --
> > 2.42.0
> >
> >
>
On Fri, 20 Oct 2023, Patrick Palka wrote:
> On Fri, 20 Oct 2023, Patrick Palka wrote:
>
> > On Fri, 20 Oct 2023, Ken Matsui wrote:
> >
> > > This patch implements built-in trait for std::is_invocable.
> >
> > Nice! My email client unfortunately ate my first review attempt, so
> > apologies for my brevity this time around.
> >
> > > gcc/cp/ChangeLog:
> > >
> > > * cp-trait.def: Define __is_invocable.
> > > * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_INVOCABLE.
> > > * semantics.cc (trait_expr_value): Likewise.
> > > (finish_trait_expr): Likewise.
> > > (is_invocable_p): New function.
> > > * method.h: New file to export build_trait_object in method.cc.
> > >
> > > gcc/testsuite/ChangeLog:
> > >
> > > * g++.dg/ext/has-builtin-1.C: Test existence of __is_invocable.
> > > * g++.dg/ext/is_invocable1.C: New test.
> > > * g++.dg/ext/is_invocable2.C: New test.
> > > * g++.dg/ext/is_invocable3.C: New test.
> > > * g++.dg/ext/is_invocable4.C: New test.
> > >
> > > Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> > > ---
> > > gcc/cp/constraint.cc | 6 +
> > > gcc/cp/cp-trait.def | 1 +
> > > gcc/cp/method.h | 28 ++
> > > gcc/cp/semantics.cc | 135 +++++++++
> > > gcc/testsuite/g++.dg/ext/has-builtin-1.C | 3 +
> > > gcc/testsuite/g++.dg/ext/is_invocable1.C | 337 +++++++++++++++++++++++
> > > gcc/testsuite/g++.dg/ext/is_invocable2.C | 139 ++++++++++
> > > gcc/testsuite/g++.dg/ext/is_invocable3.C | 51 ++++
> > > gcc/testsuite/g++.dg/ext/is_invocable4.C | 33 +++
> > > 9 files changed, 733 insertions(+)
> > > create mode 100644 gcc/cp/method.h
> > > create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable1.C
> > > create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable2.C
> > > create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable3.C
> > > create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable4.C
> > >
> > > diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> > > index 9fce36e12d1..29bf548d30a 100644
> > > --- a/gcc/cp/constraint.cc
> > > +++ b/gcc/cp/constraint.cc
> > > @@ -3754,6 +3754,12 @@ diagnose_trait_expr (tree expr, tree args)
> > > case CPTK_IS_FUNCTION:
> > > inform (loc, " %qT is not a function", t1);
> > > break;
> > > + case CPTK_IS_INVOCABLE:
> > > + if (!t2)
> > > + inform (loc, " %qT is not invocable", t1);
> > > + else
> > > + inform (loc, " %qT is not invocable by %qE", t1, t2);
> > > + break;
> > > case CPTK_IS_LAYOUT_COMPATIBLE:
> > > inform (loc, " %qT is not layout compatible with %qT", t1, t2);
> > > break;
> > > diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> > > index 05514a51c21..b8b7608c122 100644
> > > --- a/gcc/cp/cp-trait.def
> > > +++ b/gcc/cp/cp-trait.def
> > > @@ -71,6 +71,7 @@ DEFTRAIT_EXPR (IS_EMPTY, "__is_empty", 1)
> > > DEFTRAIT_EXPR (IS_ENUM, "__is_enum", 1)
> > > DEFTRAIT_EXPR (IS_FINAL, "__is_final", 1)
> > > DEFTRAIT_EXPR (IS_FUNCTION, "__is_function", 1)
> > > +DEFTRAIT_EXPR (IS_INVOCABLE, "__is_invocable", -1)
> > > DEFTRAIT_EXPR (IS_LAYOUT_COMPATIBLE, "__is_layout_compatible", 2)
> > > DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 1)
> > > DEFTRAIT_EXPR (IS_MEMBER_FUNCTION_POINTER, "__is_member_function_pointer", 1)
> > > diff --git a/gcc/cp/method.h b/gcc/cp/method.h
> > > new file mode 100644
> > > index 00000000000..1aec8ec5cfd
> > > --- /dev/null
> > > +++ b/gcc/cp/method.h
> > > @@ -0,0 +1,28 @@
> > > +/* Functions exported by method.cc.
> > > + Copyright (C) 2023 Free Software Foundation, Inc.
> > > +
> > > +This file is part of GCC.
> > > +
> > > +GCC is free software; you can redistribute it and/or modify
> > > +it under the terms of the GNU General Public License as published by
> > > +the Free Software Foundation; either version 3, or (at your option)
> > > +any later version.
> > > +
> > > +GCC is distributed in the hope that it will be useful,
> > > +but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > > +GNU General Public License for more details.
> > > +
> > > +You should have received a copy of the GNU General Public License
> > > +along with GCC; see the file COPYING3. If not see
> > > +<http://www.gnu.org/licenses/>. */
> > > +
> > > +#ifndef GCC_CP_METHOD_H
> > > +#define GCC_CP_METHOD_H 1
> > > +
> > > +#include "tree.h"
> > > +
> > > +/* In method.cc */
> > > +extern tree build_trait_object (tree type);
> >
> > Since other method.cc exports are already declared in cp-tree.h, for now
> > let's just declare this in cp-tree.h as well (under build_stub_object)
> > instead of creating a new header file.
> >
> > > +
> > > +#endif /* GCC_CP_METHOD_H */
> > > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> > > index 7cccbae5287..cc2e400531a 100644
> > > --- a/gcc/cp/semantics.cc
> > > +++ b/gcc/cp/semantics.cc
> > > @@ -45,6 +45,10 @@ along with GCC; see the file COPYING3. If not see
> > > #include "gomp-constants.h"
> > > #include "predict.h"
> > > #include "memmodel.h"
> > > +#include "method.h"
> > > +
> > > +#include "print-tree.h"
> > > +#include "tree-pretty-print.h"
> > >
> > > /* There routines provide a modular interface to perform many parsing
> > > operations. They may therefore be used during actual parsing, or
> > > @@ -11714,6 +11718,133 @@ classtype_has_nothrow_assign_or_copy_p (tree type, bool assign_p)
> > > return saw_copy;
> > > }
> > >
> > > +/* Return true if FN_TYPE is invocable with the given ARG_TYPES. */
> > > +
> > > +static bool
> > > +is_invocable_p (tree fn_type, tree arg_types)
(Sorry for the spam) We'll eventually want to implement a built-in for
invoke_result, so perhaps we should preemptively factor out the bulk
of this function into a 'build_INVOKE' helper function that returns the
built tree?
> > > +{
> > > + /* ARG_TYPES must be a TREE_VEC. */
> > > + gcc_assert (TREE_CODE (arg_types) == TREE_VEC);
> > > +
> > > + /* Access check is required to determine if the given is invocable. */
> > > + deferring_access_check_sentinel acs (dk_no_deferred);
> > > +
> > > + /* std::is_invocable is an unevaluated context. */
> > > + cp_unevaluated cp_uneval_guard;
> > > +
> > > + bool is_ptrdatamem;
> > > + bool is_ptrmemfunc;
> > > + if (TREE_CODE (fn_type) == REFERENCE_TYPE)
> > > + {
> > > + tree deref_fn_type = TREE_TYPE (fn_type);
> > > + is_ptrdatamem = TYPE_PTRDATAMEM_P (deref_fn_type);
> > > + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (deref_fn_type);
> > > +
> > > + /* Dereference fn_type if it is a pointer to member. */
> > > + if (is_ptrdatamem || is_ptrmemfunc)
> > > + fn_type = deref_fn_type;
> > > + }
> > > + else
> > > + {
> > > + is_ptrdatamem = TYPE_PTRDATAMEM_P (fn_type);
> > > + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (fn_type);
> > > + }
> > > +
> > > + if (is_ptrdatamem && TREE_VEC_LENGTH (arg_types) != 1)
> > > + /* A pointer to data member with non-one argument is not invocable. */
> > > + return false;
> > > +
> > > + if (is_ptrmemfunc && TREE_VEC_LENGTH (arg_types) == 0)
> > > + /* A pointer to member function with no arguments is not invocable. */
> > > + return false;
> > > +
> > > + /* Construct an expression of a pointer to member. */
> > > + tree datum;
> > > + if (is_ptrdatamem || is_ptrmemfunc)
> > > + {
> > > + tree datum_type = TREE_VEC_ELT (arg_types, 0);
> > > +
> > > + /* Dereference datum. */
> > > + if (CLASS_TYPE_P (datum_type))
> > > + {
> > > + bool is_refwrap = false;
> > > +
> > > + tree datum_decl = TYPE_NAME (TYPE_MAIN_VARIANT (datum_type));
> > > + if (decl_in_std_namespace_p (datum_decl))
> > > + {
> > > + tree name = DECL_NAME (datum_decl);
> > > + if (name && (id_equal (name, "reference_wrapper")))
> > > + {
> > > + /* Handle std::reference_wrapper. */
> > > + is_refwrap = true;
> > > + datum_type = cp_build_reference_type (datum_type, false);
> > > + }
> > > + }
> > > +
> > > + datum = build_trait_object (datum_type);
> > > +
> > > + /* If datum_type was not std::reference_wrapper, check if it has
> > > + operator*() overload. If datum_type was std::reference_wrapper,
> > > + avoid dereferencing the datum twice. */
> > > + if (!is_refwrap)
> > > + if (get_class_binding (datum_type, get_identifier ("operator*")))
> >
> > We probably should use lookup_member instead of get_class_binding since
> > IIUC the latter doesn't look into bases:
> >
> > struct A { int m; };
> > struct B { A& operator*(): };
> > struct C : B { };
> > static_assert(std::is_invocable_v<int A::*, C>);
> >
> > However, I notice that the specification of INVOKE
> > (https://eel.is/c++draft/func.require#lib:INVOKE) doesn't mention name
> > lookup at all so it strikes me as suspicious that we'd perform name
> > lookup here. I think this would misbehave for:
> >
> > struct A { };
> > struct B : A { A& operator*() = delete; };
> > static_assert(std::is_invocable_v<int A::*, B>);
> >
> > struct C : private A { A& operator*(); };
> > static_assert(std::is_invocable_v<int A::*, C>);
>
> Oops, this static_assert is missing a !
>
> >
> > ultimately because we end up choosing the dereference form of INVOKE,
> > but according to 1.1/1.4 we should choose the non-dereference form?
> >
> > > + /* Handle operator*(). */
> > > + datum = build_x_indirect_ref (UNKNOWN_LOCATION, datum,
> > > + RO_UNARY_STAR, NULL_TREE,
> > > + tf_none);
> > > + }
> > > + else if (POINTER_TYPE_P (datum_type))
> > > + datum = build_trait_object (TREE_TYPE (datum_type));
> > > + else
> > > + datum = build_trait_object (datum_type);
> > > + }
> > > +
> > > + /* Build a function expression. */
> > > + tree fn;
> > > + if (is_ptrdatamem)
> > > + fn = build_m_component_ref (datum, build_trait_object (fn_type), tf_none);
> >
> > Maybe exit early for the is_ptrdatamem case here (and simplify the rest
> > of the function accordingly)?
> >
> > > + else if (is_ptrmemfunc)
> > > + fn = build_trait_object (TYPE_PTRMEMFUNC_FN_TYPE (fn_type));
> > > + else
> > > + fn = build_trait_object (fn_type);
> > > +
> > > + /* Construct arguments to the function and an expression of a call. */
> > > + if (!is_ptrdatamem)
> > > + {
> > > + releasing_vec args;
> > > +
> > > + if (is_ptrmemfunc)
> > > + {
> > > + /* A pointer to member function is internally converted to a pointer
> > > + to function that takes a pointer to the dereferenced datum type
> > > + as its first argument and original arguments afterward. If the
> > > + function is a const member function, the first argument also
> > > + requires a const datum pointer and vice-versa. */
> > > +
> > > + tree datum_type = TREE_TYPE (datum);
> > > + if (TYPE_REF_P (datum_type))
> > > + datum_type = TREE_TYPE (datum_type);
> > > +
> > > + datum = build_trait_object (build_pointer_type (datum_type));
> > > + vec_safe_push (args, datum);
> > > + }
> > > +
> > > + for (int i = is_ptrmemfunc ? 1 : 0; i < TREE_VEC_LENGTH (arg_types); ++i)
> > > + {
> > > + tree arg_type = TREE_VEC_ELT (arg_types, i);
> > > + tree arg = build_trait_object (arg_type);
> > > + vec_safe_push (args, arg);
> > > + }
> > > +
> > > + fn = finish_call_expr (fn, &args, false, false, tf_none);
> > > + }
> > > +
> > > + if (error_operand_p (fn))
> > > + return false;
> > > +
> > > + return true;
> > > +}
> > > +
> > > /* Return true if DERIVED is pointer interconvertible base of BASE. */
> > >
> > > static bool
> > > @@ -12181,6 +12312,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> > > case CPTK_IS_FUNCTION:
> > > return type_code1 == FUNCTION_TYPE;
> > >
> > > + case CPTK_IS_INVOCABLE:
> > > + return is_invocable_p (type1, type2);
> > > +
> > > case CPTK_IS_LAYOUT_COMPATIBLE:
> > > return layout_compatible_type_p (type1, type2);
> > >
> > > @@ -12390,6 +12524,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
> > > break;
> > >
> > > case CPTK_IS_CONVERTIBLE:
> > > + case CPTK_IS_INVOCABLE:
> > > case CPTK_IS_NOTHROW_ASSIGNABLE:
> > > case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > > case CPTK_IS_NOTHROW_CONVERTIBLE:
> > > diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > > index b1430e9bd8b..3a9bda1ee03 100644
> > > --- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > > +++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > > @@ -92,6 +92,9 @@
> > > #if !__has_builtin (__is_function)
> > > # error "__has_builtin (__is_function) failed"
> > > #endif
> > > +#if !__has_builtin (__is_invocable)
> > > +# error "__has_builtin (__is_invocable) failed"
> > > +#endif
> > > #if !__has_builtin (__is_layout_compatible)
> > > # error "__has_builtin (__is_layout_compatible) failed"
> > > #endif
> > > diff --git a/gcc/testsuite/g++.dg/ext/is_invocable1.C b/gcc/testsuite/g++.dg/ext/is_invocable1.C
> > > new file mode 100644
> > > index 00000000000..2fd3906b571
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/ext/is_invocable1.C
> > > @@ -0,0 +1,337 @@
> > > +// { dg-do compile { target c++11 } }
> > > +
> > > +#define SA(X) static_assert((X),#X)
> > > +
> > > +using func_type_v0 = void(*)();
> > > +
> > > +SA( __is_invocable( func_type_v0 ) );
> > > +SA( ! __is_invocable( func_type_v0, int ) );
> > > +
> > > +using func_type_i0 = int(*)();
> > > +
> > > +SA( __is_invocable( func_type_i0 ) );
> > > +SA( ! __is_invocable( func_type_i0, int ) );
> > > +
> > > +using func_type_l0 = int&(*)();
> > > +
> > > +SA( __is_invocable( func_type_l0 ) );
> > > +SA( ! __is_invocable( func_type_l0(int) ) );
> > > +
> > > +using func_type_ii = int(*)(int);
> > > +
> > > +SA( ! __is_invocable( func_type_ii ) );
> > > +SA( __is_invocable( func_type_ii, int ) );
> > > +
> > > +using func_type_il = int(*)(int&);
> > > +
> > > +SA( ! __is_invocable( func_type_il ) );
> > > +SA( ! __is_invocable( func_type_il, int ) );
> > > +SA( __is_invocable( func_type_il, int& ) );
> > > +
> > > +using func_type_ir = int(*)(int&&);
> > > +
> > > +SA( ! __is_invocable( func_type_ir ) );
> > > +SA( ! __is_invocable( func_type_ir, int& ) );
> > > +SA( __is_invocable( func_type_ir, int ) );
> > > +SA( __is_invocable( func_type_ir, int&& ) );
> > > +
> > > +struct A { };
> > > +
> > > +using mem_type_i = int A::*;
> > > +
> > > +SA( ! __is_invocable( mem_type_i ) );
> > > +SA( ! __is_invocable( mem_type_i, int ) );
> > > +SA( ! __is_invocable( mem_type_i, int* ) );
> > > +SA( ! __is_invocable( mem_type_i, int& ) );
> > > +SA( ! __is_invocable( mem_type_i, int&& ) );
> > > +SA( __is_invocable( mem_type_i, A ) );
> > > +SA( __is_invocable( mem_type_i, A* ) );
> > > +SA( __is_invocable( mem_type_i, A& ) );
> > > +SA( __is_invocable( mem_type_i, A&& ) );
> > > +SA( __is_invocable( mem_type_i, const A& ) );
> > > +SA( ! __is_invocable( mem_type_i, A&, int ) );
> > > +
> > > +using memfun_type_i = int (A::*)();
> > > +
> > > +SA( ! __is_invocable( memfun_type_i ) );
> > > +SA( ! __is_invocable( memfun_type_i, int ) );
> > > +SA( ! __is_invocable( memfun_type_i, int* ) );
> > > +SA( ! __is_invocable( memfun_type_i, int& ) );
> > > +SA( ! __is_invocable( memfun_type_i, int&& ) );
> > > +SA( __is_invocable( memfun_type_i, A ) );
> > > +SA( __is_invocable( memfun_type_i, A* ) );
> > > +SA( __is_invocable( memfun_type_i, A& ) );
> > > +SA( __is_invocable( memfun_type_i, A&& ) );
> > > +SA( ! __is_invocable( memfun_type_i, const A& ) );
> > > +SA( ! __is_invocable( memfun_type_i, A&, int ) );
> > > +
> > > +using memfun_type_ic = int (A::*)() const;
> > > +
> > > +SA( ! __is_invocable( memfun_type_ic ) );
> > > +SA( ! __is_invocable( memfun_type_ic, int ) );
> > > +SA( ! __is_invocable( memfun_type_ic, int& ) );
> > > +SA( __is_invocable( memfun_type_ic, A& ) );
> > > +SA( __is_invocable( memfun_type_ic, A* ) );
> > > +SA( ! __is_invocable( memfun_type_ic, A&, int ) );
> > > +SA( ! __is_invocable( memfun_type_ic, A*, int& ) );
> > > +SA( __is_invocable( memfun_type_ic, const A& ) );
> > > +SA( __is_invocable( memfun_type_ic, const A* ) );
> > > +SA( ! __is_invocable( memfun_type_ic, const A&, int& ) );
> > > +SA( ! __is_invocable( memfun_type_ic, const A*, int ) );
> > > +
> > > +using memfun_type_iic = int& (A::*)(int&) const;
> > > +
> > > +SA( ! __is_invocable( memfun_type_iic ) );
> > > +SA( ! __is_invocable( memfun_type_iic, int ) );
> > > +SA( ! __is_invocable( memfun_type_iic, int& ) );
> > > +SA( ! __is_invocable( memfun_type_iic, A&, int ) );
> > > +SA( __is_invocable( memfun_type_iic, A&, int& ) );
> > > +SA( ! __is_invocable( memfun_type_iic, A*, int ) );
> > > +SA( __is_invocable( memfun_type_iic, A*, int& ) );
> > > +SA( ! __is_invocable( memfun_type_iic, const A&, int ) );
> > > +SA( ! __is_invocable( memfun_type_iic, const A&, int&, int ) );
> > > +SA( __is_invocable( memfun_type_iic, const A&, int& ) );
> > > +SA( __is_invocable( memfun_type_iic, const A*, int& ) );
> > > +
> > > +struct B {
> > > + int& operator()();
> > > + long& operator()() const;
> > > + bool& operator()(int);
> > > +private:
> > > + void operator()(int, int);
> > > +};
> > > +using CB = const B;
> > > +
> > > +SA( __is_invocable( B ) );
> > > +SA( __is_invocable( B& ) );
> > > +SA( __is_invocable( B&& ) );
> > > +SA( ! __is_invocable( B* ) );
> > > +SA( __is_invocable( CB ) );
> > > +SA( __is_invocable( CB& ) );
> > > +SA( ! __is_invocable( CB* ) );
> > > +
> > > +SA( __is_invocable( B, int ) );
> > > +SA( __is_invocable( B&, int ) );
> > > +SA( __is_invocable( B&&, int ) );
> > > +SA( ! __is_invocable( B*, int ) );
> > > +SA( ! __is_invocable( CB, int ) );
> > > +SA( ! __is_invocable( CB&, int ) );
> > > +SA( ! __is_invocable( CB*, int ) );
> > > +
> > > +SA( ! __is_invocable( B, int, int ) );
> > > +SA( ! __is_invocable( B&, int, int ) );
> > > +SA( ! __is_invocable( B&&, int, int ) );
> > > +SA( ! __is_invocable( B*, int, int ) );
> > > +SA( ! __is_invocable( CB, int, int ) );
> > > +SA( ! __is_invocable( CB&, int, int ) );
> > > +SA( ! __is_invocable( CB*, int, int ) );
> > > +
> > > +struct C : B { int& operator()() = delete; };
> > > +using CC = const C;
> > > +
> > > +SA( ! __is_invocable( C ) );
> > > +SA( ! __is_invocable( C& ) );
> > > +SA( ! __is_invocable( C&& ) );
> > > +SA( ! __is_invocable( C* ) );
> > > +SA( ! __is_invocable( CC ) );
> > > +SA( ! __is_invocable( CC& ) );
> > > +SA( ! __is_invocable( CC* ) );
> > > +
> > > +struct D { B operator*(); };
> > > +using CD = const D;
> > > +
> > > +SA( ! __is_invocable( D ) );
> > > +
> > > +struct E { void v(); };
> > > +using CE = const E;
> > > +
> > > +SA( ! __is_invocable( E ) );
> > > +SA( ! __is_invocable( void (E::*)() ) );
> > > +SA( __is_invocable( void (E::*)(), E ) );
> > > +SA( __is_invocable( void (E::*)(), E* ) );
> > > +SA( ! __is_invocable( void (E::*)(), CE ) );
> > > +
> > > +struct F : E {};
> > > +using CF = const F;
> > > +
> > > +SA( ! __is_invocable( F ) );
> > > +SA( __is_invocable( void (E::*)(), F ) );
> > > +SA( __is_invocable( void (E::*)(), F* ) );
> > > +SA( ! __is_invocable( void (E::*)(), CF ) );
> > > +
> > > +struct G { E operator*(); };
> > > +using CG = const G;
> > > +
> > > +SA( ! __is_invocable( G ) );
> > > +SA( __is_invocable( void (E::*)(), G ) );
> > > +SA( ! __is_invocable( void (E::*)(), G* ) );
> > > +SA( ! __is_invocable( void (E::*)(), CG ) );
> > > +
> > > +struct H { E& operator*(); };
> > > +using CH = const H;
> > > +
> > > +SA( ! __is_invocable( H ) );
> > > +SA( __is_invocable( void (E::*)(), H ) );
> > > +SA( ! __is_invocable( void (E::*)(), H* ) );
> > > +SA( ! __is_invocable( void (E::*)(), CH ) );
> > > +
> > > +struct I { E&& operator*(); };
> > > +using CI = const I;
> > > +
> > > +SA( ! __is_invocable( I ) );
> > > +SA( __is_invocable( void (E::*)(), I ) );
> > > +SA( ! __is_invocable( void (E::*)(), I* ) );
> > > +SA( ! __is_invocable( void (E::*)(), CI ) );
> > > +
> > > +struct K { E* operator*(); };
> > > +using CK = const K;
> > > +
> > > +SA( ! __is_invocable( K ) );
> > > +SA( ! __is_invocable( void (E::*)(), K ) );
> > > +SA( ! __is_invocable( void (E::*)(), K* ) );
> > > +SA( ! __is_invocable( void (E::*)(), CK ) );
> > > +
> > > +struct L { CE operator*(); };
> > > +using CL = const L;
> > > +
> > > +SA( ! __is_invocable( L ) );
> > > +SA( ! __is_invocable( void (E::*)(), L ) );
> > > +SA( ! __is_invocable( void (E::*)(), L* ) );
> > > +SA( ! __is_invocable( void (E::*)(), CL ) );
> > > +
> > > +struct M {
> > > + int i;
> > > +private:
> > > + long l;
> > > +};
> > > +using CM = const M;
> > > +
> > > +SA( ! __is_invocable( M ) );
> > > +SA( ! __is_invocable( M& ) );
> > > +SA( ! __is_invocable( M&& ) );
> > > +SA( ! __is_invocable( M* ) );
> > > +SA( ! __is_invocable( CM ) );
> > > +SA( ! __is_invocable( CM& ) );
> > > +SA( ! __is_invocable( CM* ) );
> > > +
> > > +SA( ! __is_invocable( int M::* ) );
> > > +SA( __is_invocable( int M::*, M ) );
> > > +SA( __is_invocable( int M::*, M& ) );
> > > +SA( __is_invocable( int M::*, M&& ) );
> > > +SA( __is_invocable( int M::*, M* ) );
> > > +SA( __is_invocable( int M::*, CM ) );
> > > +SA( __is_invocable( int M::*, CM& ) );
> > > +SA( __is_invocable( int M::*, CM* ) );
> > > +SA( ! __is_invocable( int M::*, int ) );
> > > +
> > > +SA( ! __is_invocable( int CM::* ) );
> > > +SA( __is_invocable( int CM::*, M ) );
> > > +SA( __is_invocable( int CM::*, M& ) );
> > > +SA( __is_invocable( int CM::*, M&& ) );
> > > +SA( __is_invocable( int CM::*, M* ) );
> > > +SA( __is_invocable( int CM::*, CM ) );
> > > +SA( __is_invocable( int CM::*, CM& ) );
> > > +SA( __is_invocable( int CM::*, CM* ) );
> > > +SA( ! __is_invocable( int CM::*, int ) );
> > > +
> > > +SA( ! __is_invocable( long M::* ) );
> > > +SA( __is_invocable( long M::*, M ) );
> > > +SA( __is_invocable( long M::*, M& ) );
> > > +SA( __is_invocable( long M::*, M&& ) );
> > > +SA( __is_invocable( long M::*, M* ) );
> > > +SA( __is_invocable( long M::*, CM ) );
> > > +SA( __is_invocable( long M::*, CM& ) );
> > > +SA( __is_invocable( long M::*, CM* ) );
> > > +SA( ! __is_invocable( long M::*, long ) );
> > > +
> > > +SA( ! __is_invocable( long CM::* ) );
> > > +SA( __is_invocable( long CM::*, M ) );
> > > +SA( __is_invocable( long CM::*, M& ) );
> > > +SA( __is_invocable( long CM::*, M&& ) );
> > > +SA( __is_invocable( long CM::*, M* ) );
> > > +SA( __is_invocable( long CM::*, CM ) );
> > > +SA( __is_invocable( long CM::*, CM& ) );
> > > +SA( __is_invocable( long CM::*, CM* ) );
> > > +SA( ! __is_invocable( long CM::*, long ) );
> > > +
> > > +SA( ! __is_invocable( short M::* ) );
> > > +SA( __is_invocable( short M::*, M ) );
> > > +SA( __is_invocable( short M::*, M& ) );
> > > +SA( __is_invocable( short M::*, M&& ) );
> > > +SA( __is_invocable( short M::*, M* ) );
> > > +SA( __is_invocable( short M::*, CM ) );
> > > +SA( __is_invocable( short M::*, CM& ) );
> > > +SA( __is_invocable( short M::*, CM* ) );
> > > +SA( ! __is_invocable( short M::*, short ) );
> > > +
> > > +SA( ! __is_invocable( short CM::* ) );
> > > +SA( __is_invocable( short CM::*, M ) );
> > > +SA( __is_invocable( short CM::*, M& ) );
> > > +SA( __is_invocable( short CM::*, M&& ) );
> > > +SA( __is_invocable( short CM::*, M* ) );
> > > +SA( __is_invocable( short CM::*, CM ) );
> > > +SA( __is_invocable( short CM::*, CM& ) );
> > > +SA( __is_invocable( short CM::*, CM* ) );
> > > +SA( ! __is_invocable( short CM::*, short ) );
> > > +
> > > +struct N { M operator*(); };
> > > +SA( __is_invocable( int M::*, N ) );
> > > +SA( ! __is_invocable( int M::*, N* ) );
> > > +
> > > +struct O { M& operator*(); };
> > > +SA( __is_invocable( int M::*, O ) );
> > > +SA( ! __is_invocable( int M::*, O* ) );
> > > +
> > > +struct P { M&& operator*(); };
> > > +SA( __is_invocable( int M::*, P ) );
> > > +SA( ! __is_invocable( int M::*, P* ) );
> > > +
> > > +struct Q { M* operator*(); };
> > > +SA( ! __is_invocable( int M::*, Q ) );
> > > +SA( ! __is_invocable( int M::*, Q* ) );
> > > +
> > > +struct R { void operator()(int = 0); };
> > > +
> > > +SA( __is_invocable( R ) );
> > > +SA( __is_invocable( R, int ) );
> > > +SA( ! __is_invocable( R, int, int ) );
> > > +
> > > +struct S { void operator()(int, ...); };
> > > +
> > > +SA( ! __is_invocable( S ) );
> > > +SA( __is_invocable( S, int ) );
> > > +SA( __is_invocable( S, int, int ) );
> > > +SA( __is_invocable( S, int, int, int ) );
> > > +
> > > +void fn1() {}
> > > +
> > > +SA( __is_invocable( decltype(fn1) ) );
> > > +
> > > +void fn2(int arr[10]);
> > > +
> > > +SA( __is_invocable( decltype(fn2), int[10] ) );
> > > +SA( __is_invocable( decltype(fn2), int(&)[10] ) );
> > > +SA( __is_invocable( decltype(fn2), int(&&)[10] ) );
> > > +SA( ! __is_invocable( decltype(fn2), int(*)[10] ) );
> > > +SA( ! __is_invocable( decltype(fn2), int(*&)[10] ) );
> > > +SA( ! __is_invocable( decltype(fn2), int(*&&)[10] ) );
> > > +SA( __is_invocable( decltype(fn2), int[] ) );
> > > +
> > > +auto lambda = []() {};
> > > +
> > > +SA( __is_invocable( decltype(lambda) ) );
> > > +
> > > +template <typename Func, typename... Args>
> > > +struct can_invoke {
> > > + static constexpr bool value = __is_invocable( Func, Args... );
> > > +};
> > > +
> > > +SA( can_invoke<decltype(lambda)>::value );
> > > +
> > > +struct T {
> > > + void func() const {}
> > > + int data;
> > > +};
> > > +
> > > +SA( __is_invocable( decltype(&T::func)&, T& ) );
> > > +SA( __is_invocable( decltype(&T::data)&, T& ) );
> > > diff --git a/gcc/testsuite/g++.dg/ext/is_invocable2.C b/gcc/testsuite/g++.dg/ext/is_invocable2.C
> > > new file mode 100644
> > > index 00000000000..a68aefd3e13
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/ext/is_invocable2.C
> > > @@ -0,0 +1,139 @@
> > > +// { dg-do compile { target c++11 } }
> > > +// __is_invocable should handle std::reference_wrapper correctly.
> > > +
> > > +#include <functional>
> > > +
> > > +#define SA(X) static_assert((X),#X)
> > > +
> > > +using std::reference_wrapper;
> > > +
> > > +using func_type_v0 = void(*)();
> > > +
> > > +SA( __is_invocable( reference_wrapper<func_type_v0> ) );
> > > +SA( ! __is_invocable( reference_wrapper<func_type_v0>, int ) );
> > > +
> > > +using func_type_i0 = int(*)();
> > > +
> > > +SA( __is_invocable( reference_wrapper<func_type_i0> ) );
> > > +SA( ! __is_invocable( reference_wrapper<func_type_i0>, int ) );
> > > +
> > > +using func_type_l0 = int&(*)();
> > > +
> > > +SA( __is_invocable( reference_wrapper<func_type_l0> ) );
> > > +SA( ! __is_invocable( reference_wrapper<func_type_l0(int)> ) );
> > > +
> > > +using func_type_ii = int(*)(int);
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<func_type_ii> ) );
> > > +SA( __is_invocable( reference_wrapper<func_type_ii>, int ) );
> > > +
> > > +using func_type_il = int(*)(int&);
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<func_type_il> ) );
> > > +SA( ! __is_invocable( reference_wrapper<func_type_il>, int ) );
> > > +SA( __is_invocable( reference_wrapper<func_type_il>, int& ) );
> > > +
> > > +using func_type_ir = int(*)(int&&);
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<func_type_ir> ) );
> > > +SA( ! __is_invocable( reference_wrapper<func_type_ir>, int& ) );
> > > +SA( __is_invocable( reference_wrapper<func_type_ir>, int ) );
> > > +SA( __is_invocable( reference_wrapper<func_type_ir>, int&& ) );
> > > +
> > > +struct A { };
> > > +
> > > +using mem_type_i = int A::*;
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<mem_type_i> ) );
> > > +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int ) );
> > > +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int* ) );
> > > +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int& ) );
> > > +SA( ! __is_invocable( reference_wrapper<mem_type_i>, int&& ) );
> > > +SA( __is_invocable( reference_wrapper<mem_type_i>, A ) );
> > > +SA( __is_invocable( reference_wrapper<mem_type_i>, A* ) );
> > > +SA( __is_invocable( reference_wrapper<mem_type_i>, A& ) );
> > > +SA( __is_invocable( reference_wrapper<mem_type_i>, A&& ) );
> > > +
> > > +using memfun_type_i = int (A::*)();
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_i> ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int* ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int& ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int&& ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_i>, A ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_i>, A* ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_i>, A& ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_i>, A&& ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, const A& ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_i>, A&, int ) );
> > > +
> > > +using memfun_type_ic = int (A::*)() const;
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic> ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, int ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, int& ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_ic>, A& ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_ic>, A* ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, A&, int ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, A*, int& ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_ic>, const A& ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_ic>, const A* ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, const A&, int& ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, const A*, int ) );
> > > +
> > > +using memfun_type_iic = int& (A::*)(int&) const;
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic> ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, int ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, int& ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, A&, int ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_iic>, A&, int& ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, A*, int ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_iic>, A*, int& ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int ) );
> > > +SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int&, int ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int& ) );
> > > +SA( __is_invocable( reference_wrapper<memfun_type_iic>, const A*, int& ) );
> > > +
> > > +struct B {
> > > + int& operator()();
> > > + long& operator()() const;
> > > + bool& operator()(int);
> > > +private:
> > > + void operator()(int, int);
> > > +};
> > > +using CB = const B;
> > > +
> > > +SA( __is_invocable( reference_wrapper<B> ) );
> > > +SA( __is_invocable( reference_wrapper<B>& ) );
> > > +SA( __is_invocable( reference_wrapper<B>&& ) );
> > > +SA( __is_invocable( reference_wrapper<CB> ) );
> > > +SA( __is_invocable( reference_wrapper<CB>& ) );
> > > +SA( __is_invocable( reference_wrapper<B>, int ) );
> > > +SA( ! __is_invocable( reference_wrapper<B>&, int, int ) );
> > > +
> > > +struct C : B { int& operator()() = delete; };
> > > +using CC = const C;
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<C> ) );
> > > +SA( ! __is_invocable( reference_wrapper<C>& ) );
> > > +SA( ! __is_invocable( reference_wrapper<C>&& ) );
> > > +SA( ! __is_invocable( reference_wrapper<CC> ) );
> > > +SA( ! __is_invocable( reference_wrapper<CC>& ) );
> > > +
> > > +struct D { B operator*(); };
> > > +using CD = const D;
> > > +
> > > +SA( ! __is_invocable( reference_wrapper<D> ) );
> > > +SA( ! __is_invocable( reference_wrapper<D>& ) );
> > > +SA( ! __is_invocable( reference_wrapper<D>&& ) );
> > > +SA( ! __is_invocable( reference_wrapper<D>* ) );
> > > +SA( ! __is_invocable( reference_wrapper<D*> ) );
> > > +SA( ! __is_invocable( reference_wrapper<D*>* ) );
> > > +
> > > +std::function<void()> fn = []() {};
> > > +auto refwrap = std::ref(fn);
> > > +
> > > +SA( __is_invocable( decltype(fn) ) );
> > > +SA( __is_invocable( decltype(refwrap) ) );
> > > diff --git a/gcc/testsuite/g++.dg/ext/is_invocable3.C b/gcc/testsuite/g++.dg/ext/is_invocable3.C
> > > new file mode 100644
> > > index 00000000000..e2b0c5ef406
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/ext/is_invocable3.C
> > > @@ -0,0 +1,51 @@
> > > +// { dg-do compile { target c++11 } }
> > > +// __is_invocable should handle incomplete class correctly.
> > > +
> > > +#define SA(X) static_assert((X),#X)
> > > +
> > > +struct Incomplete;
> > > +
> > > +SA( ! __is_invocable( Incomplete ) ); // { dg-error "incomplete type" }
> > > +SA( ! __is_invocable( Incomplete, int ) ); // { dg-error "incomplete type" }
> > > +
> > > +SA( ! __is_invocable( int, Incomplete, int ) ); // { dg-error "incomplete type" }
> > > +SA( ! __is_invocable( int, Incomplete ) ); // { dg-error "incomplete type" }
> > > +
> > > +SA( ! __is_invocable( Incomplete, Incomplete() ) ); // { dg-error "incomplete type" }
> > > +SA( ! __is_invocable( Incomplete, Incomplete(int), int ) ); // { dg-error "incomplete type" }
> > > +SA( ! __is_invocable( Incomplete, Incomplete(int, int), int, int ) ); // { dg-error "incomplete type" }
> > > +
> > > +SA( ! __is_invocable( Incomplete, Incomplete(), int, int ) ); // { dg-error "incomplete type" }
> > > +
> > > +SA( ! __is_invocable( int(Incomplete), Incomplete ) ); // { dg-error "incomplete type" }
> > > +SA( ! __is_invocable( int(int, Incomplete), int, Incomplete ) ); // { dg-error "incomplete type" }
> > > +SA( ! __is_invocable( int(int, Incomplete), Incomplete, int ) ); // { dg-error "incomplete type" }
> > > +
> > > +SA( __is_invocable( int(Incomplete&), Incomplete& ) ); // { dg-bogus "incomplete type" }
> > > +SA( __is_invocable( int(int, Incomplete&), int, Incomplete& ) ); // { dg-bogus "incomplete type" }
> > > +
> > > +SA( __is_invocable( int(Incomplete&&), Incomplete&& ) ); // { dg-bogus "incomplete type" }
> > > +SA( __is_invocable( int(int, Incomplete&&), int, Incomplete&& ) ); // { dg-bogus "incomplete type" }
> > > +
> > > +SA( __is_invocable( int(const Incomplete&&), const Incomplete&& ) ); // { dg-bogus "incomplete type" }
> > > +SA( __is_invocable( int(int, const Incomplete&&), int, const Incomplete&& ) ); // { dg-bogus "incomplete type" }
> > > +
> > > +SA( __is_invocable( int(const Incomplete&), const Incomplete& ) ); // { dg-bogus "incomplete type" }
> > > +SA( __is_invocable( int(int, const Incomplete&), int, const Incomplete& ) ); // { dg-bogus "incomplete type" }
> > > +
> > > +SA( __is_invocable( int(const Incomplete&), Incomplete& ) ); // { dg-bogus "incomplete type" }
> > > +SA( __is_invocable( int(int, const Incomplete&), int, Incomplete& ) ); // { dg-bogus "incomplete type" }
> > > +
> > > +SA( __is_invocable( int Incomplete::*, const Incomplete& ) ); // { dg-bogus "incomplete type" }
> > > +SA( ! __is_invocable( void (Incomplete::*)(long&), const Incomplete*, long& ) ); // { dg-bogus "incomplete type" }
> > > +SA( __is_invocable( void (Incomplete::*)(long&) const, Incomplete*, long& ) ); // { dg-bogus "incomplete type" }
> > > +
> > > +template <typename T>
> > > +struct Holder { T t; };
> > > +
> > > +SA( __is_invocable( int(Holder<Incomplete>&), Holder<Incomplete>& ) ); // { dg-bogus "incomplete type" }
> > > +
> > > +// Define Incomplete, which is now not incomplete.
> > > +struct Incomplete { void operator()(); };
> > > +
> > > +SA( __is_invocable( Incomplete ) ); // { dg-bogus "incomplete type" }
> > > diff --git a/gcc/testsuite/g++.dg/ext/is_invocable4.C b/gcc/testsuite/g++.dg/ext/is_invocable4.C
> > > new file mode 100644
> > > index 00000000000..d1efccf08f8
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/ext/is_invocable4.C
> > > @@ -0,0 +1,33 @@
> > > +// { dg-do compile { target c++11 } }
> > > +// Failed access check should be a substitution failure, not an error.
> > > +
> > > +#define SA(X) static_assert((X),#X)
> > > +
> > > +template<bool B>
> > > +struct bool_constant { static constexpr bool value = B; };
> > > +
> > > +template<typename _Fn, typename... _ArgTypes>
> > > +struct is_invocable
> > > +: public bool_constant<__is_invocable(_Fn, _ArgTypes...)>
> > > +{ };
> > > +
> > > +#if __cpp_variable_templates
> > > +template<typename _Fn, typename... _ArgTypes>
> > > +constexpr bool is_invocable_v = __is_invocable(_Fn, _ArgTypes...);
> > > +#endif
> > > +
> > > +class Private
> > > +{
> > > + void operator()() const
> > > + {
> > > + SA( ! is_invocable<Private>::value );
> > > +#if __cpp_variable_templates
> > > + SA( ! is_invocable_v<Private> );
> > > +#endif
> > > + }
> > > +};
> > > +
> > > +SA( ! is_invocable<Private>::value );
> > > +#if __cpp_variable_templates
> > > +SA( ! is_invocable_v<Private> );
> > > +#endif
> > > --
> > > 2.42.0
> > >
> > >
> >
>
On 10/20/23 17:37, Patrick Palka wrote:
> On Fri, 20 Oct 2023, Patrick Palka wrote:
>
>> On Fri, 20 Oct 2023, Patrick Palka wrote:
>>
>>> On Fri, 20 Oct 2023, Ken Matsui wrote:
>>>
>>>> This patch implements built-in trait for std::is_invocable.
>>>
>>> Nice! My email client unfortunately ate my first review attempt, so
>>> apologies for my brevity this time around.
>>>
>>>> gcc/cp/ChangeLog:
>>>>
>>>> * cp-trait.def: Define __is_invocable.
>>>> * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_INVOCABLE.
>>>> * semantics.cc (trait_expr_value): Likewise.
>>>> (finish_trait_expr): Likewise.
>>>> (is_invocable_p): New function.
>>>> * method.h: New file to export build_trait_object in method.cc.
Given how much larger semantics.cc is than method.cc, maybe let's put
is_invocable_p in method.cc instead? And in general declarations can go
in cp-tree.h.
>>>> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
>>>> index 7cccbae5287..cc2e400531a 100644
>>>> --- a/gcc/cp/semantics.cc
>>>> +++ b/gcc/cp/semantics.cc
>>>> @@ -45,6 +45,10 @@ along with GCC; see the file COPYING3. If not see
>>>> #include "gomp-constants.h"
>>>> #include "predict.h"
>>>> #include "memmodel.h"
>>>> +#include "method.h"
>>>> +
>>>> +#include "print-tree.h"
>>>> +#include "tree-pretty-print.h"
>>>>
>>>> /* There routines provide a modular interface to perform many parsing
>>>> operations. They may therefore be used during actual parsing, or
>>>> @@ -11714,6 +11718,133 @@ classtype_has_nothrow_assign_or_copy_p (tree type, bool assign_p)
>>>> return saw_copy;
>>>> }
>>>>
>>>> +/* Return true if FN_TYPE is invocable with the given ARG_TYPES. */
>>>> +
>>>> +static bool
>>>> +is_invocable_p (tree fn_type, tree arg_types)
>
> (Sorry for the spam) We'll eventually want to implement a built-in for
> invoke_result, so perhaps we should preemptively factor out the bulk
> of this function into a 'build_INVOKE' helper function that returns the
> built tree?
>
>>>> +{
>>>> + /* ARG_TYPES must be a TREE_VEC. */
>>>> + gcc_assert (TREE_CODE (arg_types) == TREE_VEC);
>>>> +
>>>> + /* Access check is required to determine if the given is invocable. */
>>>> + deferring_access_check_sentinel acs (dk_no_deferred);
>>>> +
>>>> + /* std::is_invocable is an unevaluated context. */
>>>> + cp_unevaluated cp_uneval_guard;
>>>> +
>>>> + bool is_ptrdatamem;
>>>> + bool is_ptrmemfunc;
>>>> + if (TREE_CODE (fn_type) == REFERENCE_TYPE)
>>>> + {
>>>> + tree deref_fn_type = TREE_TYPE (fn_type);
>>>> + is_ptrdatamem = TYPE_PTRDATAMEM_P (deref_fn_type);
>>>> + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (deref_fn_type);
>>>> +
>>>> + /* Dereference fn_type if it is a pointer to member. */
>>>> + if (is_ptrdatamem || is_ptrmemfunc)
>>>> + fn_type = deref_fn_type;
>>>> + }
>>>> + else
>>>> + {
>>>> + is_ptrdatamem = TYPE_PTRDATAMEM_P (fn_type);
>>>> + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (fn_type);
>>>> + }
>>>> +
>>>> + if (is_ptrdatamem && TREE_VEC_LENGTH (arg_types) != 1)
>>>> + /* A pointer to data member with non-one argument is not invocable. */
>>>> + return false;
>>>> +
>>>> + if (is_ptrmemfunc && TREE_VEC_LENGTH (arg_types) == 0)
>>>> + /* A pointer to member function with no arguments is not invocable. */
>>>> + return false;
>>>> +
>>>> + /* Construct an expression of a pointer to member. */
>>>> + tree datum;
>>>> + if (is_ptrdatamem || is_ptrmemfunc)
>>>> + {
>>>> + tree datum_type = TREE_VEC_ELT (arg_types, 0);
>>>> +
>>>> + /* Dereference datum. */
>>>> + if (CLASS_TYPE_P (datum_type))
>>>> + {
>>>> + bool is_refwrap = false;
>>>> +
>>>> + tree datum_decl = TYPE_NAME (TYPE_MAIN_VARIANT (datum_type));
>>>> + if (decl_in_std_namespace_p (datum_decl))
>>>> + {
>>>> + tree name = DECL_NAME (datum_decl);
>>>> + if (name && (id_equal (name, "reference_wrapper")))
>>>> + {
>>>> + /* Handle std::reference_wrapper. */
>>>> + is_refwrap = true;
>>>> + datum_type = cp_build_reference_type (datum_type, false);
Why do you change datum_type from std::reference_wrapper<...> to
std::reference_wrapper<...>&?
>>>> + }
>>>> + }
>>>> +
>>>> + datum = build_trait_object (datum_type);
>>>> +
>>>> + /* If datum_type was not std::reference_wrapper, check if it has
>>>> + operator*() overload. If datum_type was std::reference_wrapper,
>>>> + avoid dereferencing the datum twice. */
>>>> + if (!is_refwrap)
>>>> + if (get_class_binding (datum_type, get_identifier ("operator*")))
>>>
>>> We probably should use lookup_member instead of get_class_binding since
>>> IIUC the latter doesn't look into bases:
>>>
>>> struct A { int m; };
>>> struct B { A& operator*(): };
>>> struct C : B { };
>>> static_assert(std::is_invocable_v<int A::*, C>);
>>>
>>> However, I notice that the specification of INVOKE
>>> (https://eel.is/c++draft/func.require#lib:INVOKE) doesn't mention name
>>> lookup at all so it strikes me as suspicious that we'd perform name
>>> lookup here.
Agreed. It seems that whether or not to build_x_indirect_ref should
depend instead on whether f is a pointer to a member of decltype(t1) (as
well as is_refwrap).
>>> I think this would misbehave for:
>>>
>>> struct A { };
>>> struct B : A { A& operator*() = delete; };
>>> static_assert(std::is_invocable_v<int A::*, B>);
>>>
>>> struct C : private A { A& operator*(); };
>>> static_assert(std::is_invocable_v<int A::*, C>);
>>
>> Oops, this static_assert is missing a !
>>
>>>
>>> ultimately because we end up choosing the dereference form of INVOKE,
>>> but according to 1.1/1.4 we should choose the non-dereference form?
>>>
>>>> + /* Handle operator*(). */
>>>> + datum = build_x_indirect_ref (UNKNOWN_LOCATION, datum,
>>>> + RO_UNARY_STAR, NULL_TREE,
>>>> + tf_none);
>>>> + }
>>>> + else if (POINTER_TYPE_P (datum_type))
>>>> + datum = build_trait_object (TREE_TYPE (datum_type));
>>>> + else
>>>> + datum = build_trait_object (datum_type);
>>>> + }
>>>> +
>>>> + /* Build a function expression. */
>>>> + tree fn;
>>>> + if (is_ptrdatamem)
>>>> + fn = build_m_component_ref (datum, build_trait_object (fn_type), tf_none);
>>>
>>> Maybe exit early for the is_ptrdatamem case here (and simplify the rest
>>> of the function accordingly)?
>>>
>>>> + else if (is_ptrmemfunc)
>>>> + fn = build_trait_object (TYPE_PTRMEMFUNC_FN_TYPE (fn_type));
Why not use build_m_component_ref and build_offset_ref_call_from_tree
like it would if you wrote (t1.*f)() directly?
Jason
On Mon, Oct 23, 2023 at 2:23 PM Jason Merrill <jason@redhat.com> wrote:
>
> On 10/20/23 17:37, Patrick Palka wrote:
> > On Fri, 20 Oct 2023, Patrick Palka wrote:
> >
> >> On Fri, 20 Oct 2023, Patrick Palka wrote:
> >>
> >>> On Fri, 20 Oct 2023, Ken Matsui wrote:
> >>>
> >>>> This patch implements built-in trait for std::is_invocable.
> >>>
> >>> Nice! My email client unfortunately ate my first review attempt, so
> >>> apologies for my brevity this time around.
> >>>
> >>>> gcc/cp/ChangeLog:
> >>>>
> >>>> * cp-trait.def: Define __is_invocable.
> >>>> * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_INVOCABLE.
> >>>> * semantics.cc (trait_expr_value): Likewise.
> >>>> (finish_trait_expr): Likewise.
> >>>> (is_invocable_p): New function.
> >>>> * method.h: New file to export build_trait_object in method.cc.
>
> Given how much larger semantics.cc is than method.cc, maybe let's put
> is_invocable_p in method.cc instead? And in general declarations can go
> in cp-tree.h.
>
> >>>> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> >>>> index 7cccbae5287..cc2e400531a 100644
> >>>> --- a/gcc/cp/semantics.cc
> >>>> +++ b/gcc/cp/semantics.cc
> >>>> @@ -45,6 +45,10 @@ along with GCC; see the file COPYING3. If not see
> >>>> #include "gomp-constants.h"
> >>>> #include "predict.h"
> >>>> #include "memmodel.h"
> >>>> +#include "method.h"
> >>>> +
> >>>> +#include "print-tree.h"
> >>>> +#include "tree-pretty-print.h"
> >>>>
> >>>> /* There routines provide a modular interface to perform many parsing
> >>>> operations. They may therefore be used during actual parsing, or
> >>>> @@ -11714,6 +11718,133 @@ classtype_has_nothrow_assign_or_copy_p (tree type, bool assign_p)
> >>>> return saw_copy;
> >>>> }
> >>>>
> >>>> +/* Return true if FN_TYPE is invocable with the given ARG_TYPES. */
> >>>> +
> >>>> +static bool
> >>>> +is_invocable_p (tree fn_type, tree arg_types)
> >
> > (Sorry for the spam) We'll eventually want to implement a built-in for
> > invoke_result, so perhaps we should preemptively factor out the bulk
> > of this function into a 'build_INVOKE' helper function that returns the
> > built tree?
> >
> >>>> +{
> >>>> + /* ARG_TYPES must be a TREE_VEC. */
> >>>> + gcc_assert (TREE_CODE (arg_types) == TREE_VEC);
> >>>> +
> >>>> + /* Access check is required to determine if the given is invocable. */
> >>>> + deferring_access_check_sentinel acs (dk_no_deferred);
> >>>> +
> >>>> + /* std::is_invocable is an unevaluated context. */
> >>>> + cp_unevaluated cp_uneval_guard;
> >>>> +
> >>>> + bool is_ptrdatamem;
> >>>> + bool is_ptrmemfunc;
> >>>> + if (TREE_CODE (fn_type) == REFERENCE_TYPE)
> >>>> + {
> >>>> + tree deref_fn_type = TREE_TYPE (fn_type);
> >>>> + is_ptrdatamem = TYPE_PTRDATAMEM_P (deref_fn_type);
> >>>> + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (deref_fn_type);
> >>>> +
> >>>> + /* Dereference fn_type if it is a pointer to member. */
> >>>> + if (is_ptrdatamem || is_ptrmemfunc)
> >>>> + fn_type = deref_fn_type;
> >>>> + }
> >>>> + else
> >>>> + {
> >>>> + is_ptrdatamem = TYPE_PTRDATAMEM_P (fn_type);
> >>>> + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (fn_type);
> >>>> + }
> >>>> +
> >>>> + if (is_ptrdatamem && TREE_VEC_LENGTH (arg_types) != 1)
> >>>> + /* A pointer to data member with non-one argument is not invocable. */
> >>>> + return false;
> >>>> +
> >>>> + if (is_ptrmemfunc && TREE_VEC_LENGTH (arg_types) == 0)
> >>>> + /* A pointer to member function with no arguments is not invocable. */
> >>>> + return false;
> >>>> +
> >>>> + /* Construct an expression of a pointer to member. */
> >>>> + tree datum;
> >>>> + if (is_ptrdatamem || is_ptrmemfunc)
> >>>> + {
> >>>> + tree datum_type = TREE_VEC_ELT (arg_types, 0);
> >>>> +
> >>>> + /* Dereference datum. */
> >>>> + if (CLASS_TYPE_P (datum_type))
> >>>> + {
> >>>> + bool is_refwrap = false;
> >>>> +
> >>>> + tree datum_decl = TYPE_NAME (TYPE_MAIN_VARIANT (datum_type));
> >>>> + if (decl_in_std_namespace_p (datum_decl))
> >>>> + {
> >>>> + tree name = DECL_NAME (datum_decl);
> >>>> + if (name && (id_equal (name, "reference_wrapper")))
> >>>> + {
> >>>> + /* Handle std::reference_wrapper. */
> >>>> + is_refwrap = true;
> >>>> + datum_type = cp_build_reference_type (datum_type, false);
>
> Why do you change datum_type from std::reference_wrapper<...> to
> std::reference_wrapper<...>&?
>
> >>>> + }
> >>>> + }
> >>>> +
> >>>> + datum = build_trait_object (datum_type);
> >>>> +
> >>>> + /* If datum_type was not std::reference_wrapper, check if it has
> >>>> + operator*() overload. If datum_type was std::reference_wrapper,
> >>>> + avoid dereferencing the datum twice. */
> >>>> + if (!is_refwrap)
> >>>> + if (get_class_binding (datum_type, get_identifier ("operator*")))
> >>>
> >>> We probably should use lookup_member instead of get_class_binding since
> >>> IIUC the latter doesn't look into bases:
> >>>
> >>> struct A { int m; };
> >>> struct B { A& operator*(): };
> >>> struct C : B { };
> >>> static_assert(std::is_invocable_v<int A::*, C>);
> >>>
> >>> However, I notice that the specification of INVOKE
> >>> (https://eel.is/c++draft/func.require#lib:INVOKE) doesn't mention name
> >>> lookup at all so it strikes me as suspicious that we'd perform name
> >>> lookup here.
>
> Agreed. It seems that whether or not to build_x_indirect_ref should
> depend instead on whether f is a pointer to a member of decltype(t1) (as
> well as is_refwrap).
>
> >>> I think this would misbehave for:
> >>>
> >>> struct A { };
> >>> struct B : A { A& operator*() = delete; };
> >>> static_assert(std::is_invocable_v<int A::*, B>);
> >>>
> >>> struct C : private A { A& operator*(); };
> >>> static_assert(std::is_invocable_v<int A::*, C>);
> >>
> >> Oops, this static_assert is missing a !
> >>
> >>>
> >>> ultimately because we end up choosing the dereference form of INVOKE,
> >>> but according to 1.1/1.4 we should choose the non-dereference form?
> >>>
> >>>> + /* Handle operator*(). */
> >>>> + datum = build_x_indirect_ref (UNKNOWN_LOCATION, datum,
> >>>> + RO_UNARY_STAR, NULL_TREE,
> >>>> + tf_none);
> >>>> + }
> >>>> + else if (POINTER_TYPE_P (datum_type))
> >>>> + datum = build_trait_object (TREE_TYPE (datum_type));
> >>>> + else
> >>>> + datum = build_trait_object (datum_type);
> >>>> + }
> >>>> +
> >>>> + /* Build a function expression. */
> >>>> + tree fn;
> >>>> + if (is_ptrdatamem)
> >>>> + fn = build_m_component_ref (datum, build_trait_object (fn_type), tf_none);
> >>>
> >>> Maybe exit early for the is_ptrdatamem case here (and simplify the rest
> >>> of the function accordingly)?
> >>>
> >>>> + else if (is_ptrmemfunc)
> >>>> + fn = build_trait_object (TYPE_PTRMEMFUNC_FN_TYPE (fn_type));
>
> Why not use build_m_component_ref and build_offset_ref_call_from_tree
> like it would if you wrote (t1.*f)() directly?
>
Thank you so much for your review! I will apply your suggestions.
> Jason
>
@@ -3754,6 +3754,12 @@ diagnose_trait_expr (tree expr, tree args)
case CPTK_IS_FUNCTION:
inform (loc, " %qT is not a function", t1);
break;
+ case CPTK_IS_INVOCABLE:
+ if (!t2)
+ inform (loc, " %qT is not invocable", t1);
+ else
+ inform (loc, " %qT is not invocable by %qE", t1, t2);
+ break;
case CPTK_IS_LAYOUT_COMPATIBLE:
inform (loc, " %qT is not layout compatible with %qT", t1, t2);
break;
@@ -71,6 +71,7 @@ DEFTRAIT_EXPR (IS_EMPTY, "__is_empty", 1)
DEFTRAIT_EXPR (IS_ENUM, "__is_enum", 1)
DEFTRAIT_EXPR (IS_FINAL, "__is_final", 1)
DEFTRAIT_EXPR (IS_FUNCTION, "__is_function", 1)
+DEFTRAIT_EXPR (IS_INVOCABLE, "__is_invocable", -1)
DEFTRAIT_EXPR (IS_LAYOUT_COMPATIBLE, "__is_layout_compatible", 2)
DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 1)
DEFTRAIT_EXPR (IS_MEMBER_FUNCTION_POINTER, "__is_member_function_pointer", 1)
new file mode 100644
@@ -0,0 +1,28 @@
+/* Functions exported by method.cc.
+ Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#ifndef GCC_CP_METHOD_H
+#define GCC_CP_METHOD_H 1
+
+#include "tree.h"
+
+/* In method.cc */
+extern tree build_trait_object (tree type);
+
+#endif /* GCC_CP_METHOD_H */
@@ -45,6 +45,10 @@ along with GCC; see the file COPYING3. If not see
#include "gomp-constants.h"
#include "predict.h"
#include "memmodel.h"
+#include "method.h"
+
+#include "print-tree.h"
+#include "tree-pretty-print.h"
/* There routines provide a modular interface to perform many parsing
operations. They may therefore be used during actual parsing, or
@@ -11714,6 +11718,133 @@ classtype_has_nothrow_assign_or_copy_p (tree type, bool assign_p)
return saw_copy;
}
+/* Return true if FN_TYPE is invocable with the given ARG_TYPES. */
+
+static bool
+is_invocable_p (tree fn_type, tree arg_types)
+{
+ /* ARG_TYPES must be a TREE_VEC. */
+ gcc_assert (TREE_CODE (arg_types) == TREE_VEC);
+
+ /* Access check is required to determine if the given is invocable. */
+ deferring_access_check_sentinel acs (dk_no_deferred);
+
+ /* std::is_invocable is an unevaluated context. */
+ cp_unevaluated cp_uneval_guard;
+
+ bool is_ptrdatamem;
+ bool is_ptrmemfunc;
+ if (TREE_CODE (fn_type) == REFERENCE_TYPE)
+ {
+ tree deref_fn_type = TREE_TYPE (fn_type);
+ is_ptrdatamem = TYPE_PTRDATAMEM_P (deref_fn_type);
+ is_ptrmemfunc = TYPE_PTRMEMFUNC_P (deref_fn_type);
+
+ /* Dereference fn_type if it is a pointer to member. */
+ if (is_ptrdatamem || is_ptrmemfunc)
+ fn_type = deref_fn_type;
+ }
+ else
+ {
+ is_ptrdatamem = TYPE_PTRDATAMEM_P (fn_type);
+ is_ptrmemfunc = TYPE_PTRMEMFUNC_P (fn_type);
+ }
+
+ if (is_ptrdatamem && TREE_VEC_LENGTH (arg_types) != 1)
+ /* A pointer to data member with non-one argument is not invocable. */
+ return false;
+
+ if (is_ptrmemfunc && TREE_VEC_LENGTH (arg_types) == 0)
+ /* A pointer to member function with no arguments is not invocable. */
+ return false;
+
+ /* Construct an expression of a pointer to member. */
+ tree datum;
+ if (is_ptrdatamem || is_ptrmemfunc)
+ {
+ tree datum_type = TREE_VEC_ELT (arg_types, 0);
+
+ /* Dereference datum. */
+ if (CLASS_TYPE_P (datum_type))
+ {
+ bool is_refwrap = false;
+
+ tree datum_decl = TYPE_NAME (TYPE_MAIN_VARIANT (datum_type));
+ if (decl_in_std_namespace_p (datum_decl))
+ {
+ tree name = DECL_NAME (datum_decl);
+ if (name && (id_equal (name, "reference_wrapper")))
+ {
+ /* Handle std::reference_wrapper. */
+ is_refwrap = true;
+ datum_type = cp_build_reference_type (datum_type, false);
+ }
+ }
+
+ datum = build_trait_object (datum_type);
+
+ /* If datum_type was not std::reference_wrapper, check if it has
+ operator*() overload. If datum_type was std::reference_wrapper,
+ avoid dereferencing the datum twice. */
+ if (!is_refwrap)
+ if (get_class_binding (datum_type, get_identifier ("operator*")))
+ /* Handle operator*(). */
+ datum = build_x_indirect_ref (UNKNOWN_LOCATION, datum,
+ RO_UNARY_STAR, NULL_TREE,
+ tf_none);
+ }
+ else if (POINTER_TYPE_P (datum_type))
+ datum = build_trait_object (TREE_TYPE (datum_type));
+ else
+ datum = build_trait_object (datum_type);
+ }
+
+ /* Build a function expression. */
+ tree fn;
+ if (is_ptrdatamem)
+ fn = build_m_component_ref (datum, build_trait_object (fn_type), tf_none);
+ else if (is_ptrmemfunc)
+ fn = build_trait_object (TYPE_PTRMEMFUNC_FN_TYPE (fn_type));
+ else
+ fn = build_trait_object (fn_type);
+
+ /* Construct arguments to the function and an expression of a call. */
+ if (!is_ptrdatamem)
+ {
+ releasing_vec args;
+
+ if (is_ptrmemfunc)
+ {
+ /* A pointer to member function is internally converted to a pointer
+ to function that takes a pointer to the dereferenced datum type
+ as its first argument and original arguments afterward. If the
+ function is a const member function, the first argument also
+ requires a const datum pointer and vice-versa. */
+
+ tree datum_type = TREE_TYPE (datum);
+ if (TYPE_REF_P (datum_type))
+ datum_type = TREE_TYPE (datum_type);
+
+ datum = build_trait_object (build_pointer_type (datum_type));
+ vec_safe_push (args, datum);
+ }
+
+ for (int i = is_ptrmemfunc ? 1 : 0; i < TREE_VEC_LENGTH (arg_types); ++i)
+ {
+ tree arg_type = TREE_VEC_ELT (arg_types, i);
+ tree arg = build_trait_object (arg_type);
+ vec_safe_push (args, arg);
+ }
+
+ fn = finish_call_expr (fn, &args, false, false, tf_none);
+ }
+
+ if (error_operand_p (fn))
+ return false;
+
+ return true;
+}
+
/* Return true if DERIVED is pointer interconvertible base of BASE. */
static bool
@@ -12181,6 +12312,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
case CPTK_IS_FUNCTION:
return type_code1 == FUNCTION_TYPE;
+ case CPTK_IS_INVOCABLE:
+ return is_invocable_p (type1, type2);
+
case CPTK_IS_LAYOUT_COMPATIBLE:
return layout_compatible_type_p (type1, type2);
@@ -12390,6 +12524,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
break;
case CPTK_IS_CONVERTIBLE:
+ case CPTK_IS_INVOCABLE:
case CPTK_IS_NOTHROW_ASSIGNABLE:
case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
case CPTK_IS_NOTHROW_CONVERTIBLE:
@@ -92,6 +92,9 @@
#if !__has_builtin (__is_function)
# error "__has_builtin (__is_function) failed"
#endif
+#if !__has_builtin (__is_invocable)
+# error "__has_builtin (__is_invocable) failed"
+#endif
#if !__has_builtin (__is_layout_compatible)
# error "__has_builtin (__is_layout_compatible) failed"
#endif
new file mode 100644
@@ -0,0 +1,337 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+using func_type_v0 = void(*)();
+
+SA( __is_invocable( func_type_v0 ) );
+SA( ! __is_invocable( func_type_v0, int ) );
+
+using func_type_i0 = int(*)();
+
+SA( __is_invocable( func_type_i0 ) );
+SA( ! __is_invocable( func_type_i0, int ) );
+
+using func_type_l0 = int&(*)();
+
+SA( __is_invocable( func_type_l0 ) );
+SA( ! __is_invocable( func_type_l0(int) ) );
+
+using func_type_ii = int(*)(int);
+
+SA( ! __is_invocable( func_type_ii ) );
+SA( __is_invocable( func_type_ii, int ) );
+
+using func_type_il = int(*)(int&);
+
+SA( ! __is_invocable( func_type_il ) );
+SA( ! __is_invocable( func_type_il, int ) );
+SA( __is_invocable( func_type_il, int& ) );
+
+using func_type_ir = int(*)(int&&);
+
+SA( ! __is_invocable( func_type_ir ) );
+SA( ! __is_invocable( func_type_ir, int& ) );
+SA( __is_invocable( func_type_ir, int ) );
+SA( __is_invocable( func_type_ir, int&& ) );
+
+struct A { };
+
+using mem_type_i = int A::*;
+
+SA( ! __is_invocable( mem_type_i ) );
+SA( ! __is_invocable( mem_type_i, int ) );
+SA( ! __is_invocable( mem_type_i, int* ) );
+SA( ! __is_invocable( mem_type_i, int& ) );
+SA( ! __is_invocable( mem_type_i, int&& ) );
+SA( __is_invocable( mem_type_i, A ) );
+SA( __is_invocable( mem_type_i, A* ) );
+SA( __is_invocable( mem_type_i, A& ) );
+SA( __is_invocable( mem_type_i, A&& ) );
+SA( __is_invocable( mem_type_i, const A& ) );
+SA( ! __is_invocable( mem_type_i, A&, int ) );
+
+using memfun_type_i = int (A::*)();
+
+SA( ! __is_invocable( memfun_type_i ) );
+SA( ! __is_invocable( memfun_type_i, int ) );
+SA( ! __is_invocable( memfun_type_i, int* ) );
+SA( ! __is_invocable( memfun_type_i, int& ) );
+SA( ! __is_invocable( memfun_type_i, int&& ) );
+SA( __is_invocable( memfun_type_i, A ) );
+SA( __is_invocable( memfun_type_i, A* ) );
+SA( __is_invocable( memfun_type_i, A& ) );
+SA( __is_invocable( memfun_type_i, A&& ) );
+SA( ! __is_invocable( memfun_type_i, const A& ) );
+SA( ! __is_invocable( memfun_type_i, A&, int ) );
+
+using memfun_type_ic = int (A::*)() const;
+
+SA( ! __is_invocable( memfun_type_ic ) );
+SA( ! __is_invocable( memfun_type_ic, int ) );
+SA( ! __is_invocable( memfun_type_ic, int& ) );
+SA( __is_invocable( memfun_type_ic, A& ) );
+SA( __is_invocable( memfun_type_ic, A* ) );
+SA( ! __is_invocable( memfun_type_ic, A&, int ) );
+SA( ! __is_invocable( memfun_type_ic, A*, int& ) );
+SA( __is_invocable( memfun_type_ic, const A& ) );
+SA( __is_invocable( memfun_type_ic, const A* ) );
+SA( ! __is_invocable( memfun_type_ic, const A&, int& ) );
+SA( ! __is_invocable( memfun_type_ic, const A*, int ) );
+
+using memfun_type_iic = int& (A::*)(int&) const;
+
+SA( ! __is_invocable( memfun_type_iic ) );
+SA( ! __is_invocable( memfun_type_iic, int ) );
+SA( ! __is_invocable( memfun_type_iic, int& ) );
+SA( ! __is_invocable( memfun_type_iic, A&, int ) );
+SA( __is_invocable( memfun_type_iic, A&, int& ) );
+SA( ! __is_invocable( memfun_type_iic, A*, int ) );
+SA( __is_invocable( memfun_type_iic, A*, int& ) );
+SA( ! __is_invocable( memfun_type_iic, const A&, int ) );
+SA( ! __is_invocable( memfun_type_iic, const A&, int&, int ) );
+SA( __is_invocable( memfun_type_iic, const A&, int& ) );
+SA( __is_invocable( memfun_type_iic, const A*, int& ) );
+
+struct B {
+ int& operator()();
+ long& operator()() const;
+ bool& operator()(int);
+private:
+ void operator()(int, int);
+};
+using CB = const B;
+
+SA( __is_invocable( B ) );
+SA( __is_invocable( B& ) );
+SA( __is_invocable( B&& ) );
+SA( ! __is_invocable( B* ) );
+SA( __is_invocable( CB ) );
+SA( __is_invocable( CB& ) );
+SA( ! __is_invocable( CB* ) );
+
+SA( __is_invocable( B, int ) );
+SA( __is_invocable( B&, int ) );
+SA( __is_invocable( B&&, int ) );
+SA( ! __is_invocable( B*, int ) );
+SA( ! __is_invocable( CB, int ) );
+SA( ! __is_invocable( CB&, int ) );
+SA( ! __is_invocable( CB*, int ) );
+
+SA( ! __is_invocable( B, int, int ) );
+SA( ! __is_invocable( B&, int, int ) );
+SA( ! __is_invocable( B&&, int, int ) );
+SA( ! __is_invocable( B*, int, int ) );
+SA( ! __is_invocable( CB, int, int ) );
+SA( ! __is_invocable( CB&, int, int ) );
+SA( ! __is_invocable( CB*, int, int ) );
+
+struct C : B { int& operator()() = delete; };
+using CC = const C;
+
+SA( ! __is_invocable( C ) );
+SA( ! __is_invocable( C& ) );
+SA( ! __is_invocable( C&& ) );
+SA( ! __is_invocable( C* ) );
+SA( ! __is_invocable( CC ) );
+SA( ! __is_invocable( CC& ) );
+SA( ! __is_invocable( CC* ) );
+
+struct D { B operator*(); };
+using CD = const D;
+
+SA( ! __is_invocable( D ) );
+
+struct E { void v(); };
+using CE = const E;
+
+SA( ! __is_invocable( E ) );
+SA( ! __is_invocable( void (E::*)() ) );
+SA( __is_invocable( void (E::*)(), E ) );
+SA( __is_invocable( void (E::*)(), E* ) );
+SA( ! __is_invocable( void (E::*)(), CE ) );
+
+struct F : E {};
+using CF = const F;
+
+SA( ! __is_invocable( F ) );
+SA( __is_invocable( void (E::*)(), F ) );
+SA( __is_invocable( void (E::*)(), F* ) );
+SA( ! __is_invocable( void (E::*)(), CF ) );
+
+struct G { E operator*(); };
+using CG = const G;
+
+SA( ! __is_invocable( G ) );
+SA( __is_invocable( void (E::*)(), G ) );
+SA( ! __is_invocable( void (E::*)(), G* ) );
+SA( ! __is_invocable( void (E::*)(), CG ) );
+
+struct H { E& operator*(); };
+using CH = const H;
+
+SA( ! __is_invocable( H ) );
+SA( __is_invocable( void (E::*)(), H ) );
+SA( ! __is_invocable( void (E::*)(), H* ) );
+SA( ! __is_invocable( void (E::*)(), CH ) );
+
+struct I { E&& operator*(); };
+using CI = const I;
+
+SA( ! __is_invocable( I ) );
+SA( __is_invocable( void (E::*)(), I ) );
+SA( ! __is_invocable( void (E::*)(), I* ) );
+SA( ! __is_invocable( void (E::*)(), CI ) );
+
+struct K { E* operator*(); };
+using CK = const K;
+
+SA( ! __is_invocable( K ) );
+SA( ! __is_invocable( void (E::*)(), K ) );
+SA( ! __is_invocable( void (E::*)(), K* ) );
+SA( ! __is_invocable( void (E::*)(), CK ) );
+
+struct L { CE operator*(); };
+using CL = const L;
+
+SA( ! __is_invocable( L ) );
+SA( ! __is_invocable( void (E::*)(), L ) );
+SA( ! __is_invocable( void (E::*)(), L* ) );
+SA( ! __is_invocable( void (E::*)(), CL ) );
+
+struct M {
+ int i;
+private:
+ long l;
+};
+using CM = const M;
+
+SA( ! __is_invocable( M ) );
+SA( ! __is_invocable( M& ) );
+SA( ! __is_invocable( M&& ) );
+SA( ! __is_invocable( M* ) );
+SA( ! __is_invocable( CM ) );
+SA( ! __is_invocable( CM& ) );
+SA( ! __is_invocable( CM* ) );
+
+SA( ! __is_invocable( int M::* ) );
+SA( __is_invocable( int M::*, M ) );
+SA( __is_invocable( int M::*, M& ) );
+SA( __is_invocable( int M::*, M&& ) );
+SA( __is_invocable( int M::*, M* ) );
+SA( __is_invocable( int M::*, CM ) );
+SA( __is_invocable( int M::*, CM& ) );
+SA( __is_invocable( int M::*, CM* ) );
+SA( ! __is_invocable( int M::*, int ) );
+
+SA( ! __is_invocable( int CM::* ) );
+SA( __is_invocable( int CM::*, M ) );
+SA( __is_invocable( int CM::*, M& ) );
+SA( __is_invocable( int CM::*, M&& ) );
+SA( __is_invocable( int CM::*, M* ) );
+SA( __is_invocable( int CM::*, CM ) );
+SA( __is_invocable( int CM::*, CM& ) );
+SA( __is_invocable( int CM::*, CM* ) );
+SA( ! __is_invocable( int CM::*, int ) );
+
+SA( ! __is_invocable( long M::* ) );
+SA( __is_invocable( long M::*, M ) );
+SA( __is_invocable( long M::*, M& ) );
+SA( __is_invocable( long M::*, M&& ) );
+SA( __is_invocable( long M::*, M* ) );
+SA( __is_invocable( long M::*, CM ) );
+SA( __is_invocable( long M::*, CM& ) );
+SA( __is_invocable( long M::*, CM* ) );
+SA( ! __is_invocable( long M::*, long ) );
+
+SA( ! __is_invocable( long CM::* ) );
+SA( __is_invocable( long CM::*, M ) );
+SA( __is_invocable( long CM::*, M& ) );
+SA( __is_invocable( long CM::*, M&& ) );
+SA( __is_invocable( long CM::*, M* ) );
+SA( __is_invocable( long CM::*, CM ) );
+SA( __is_invocable( long CM::*, CM& ) );
+SA( __is_invocable( long CM::*, CM* ) );
+SA( ! __is_invocable( long CM::*, long ) );
+
+SA( ! __is_invocable( short M::* ) );
+SA( __is_invocable( short M::*, M ) );
+SA( __is_invocable( short M::*, M& ) );
+SA( __is_invocable( short M::*, M&& ) );
+SA( __is_invocable( short M::*, M* ) );
+SA( __is_invocable( short M::*, CM ) );
+SA( __is_invocable( short M::*, CM& ) );
+SA( __is_invocable( short M::*, CM* ) );
+SA( ! __is_invocable( short M::*, short ) );
+
+SA( ! __is_invocable( short CM::* ) );
+SA( __is_invocable( short CM::*, M ) );
+SA( __is_invocable( short CM::*, M& ) );
+SA( __is_invocable( short CM::*, M&& ) );
+SA( __is_invocable( short CM::*, M* ) );
+SA( __is_invocable( short CM::*, CM ) );
+SA( __is_invocable( short CM::*, CM& ) );
+SA( __is_invocable( short CM::*, CM* ) );
+SA( ! __is_invocable( short CM::*, short ) );
+
+struct N { M operator*(); };
+SA( __is_invocable( int M::*, N ) );
+SA( ! __is_invocable( int M::*, N* ) );
+
+struct O { M& operator*(); };
+SA( __is_invocable( int M::*, O ) );
+SA( ! __is_invocable( int M::*, O* ) );
+
+struct P { M&& operator*(); };
+SA( __is_invocable( int M::*, P ) );
+SA( ! __is_invocable( int M::*, P* ) );
+
+struct Q { M* operator*(); };
+SA( ! __is_invocable( int M::*, Q ) );
+SA( ! __is_invocable( int M::*, Q* ) );
+
+struct R { void operator()(int = 0); };
+
+SA( __is_invocable( R ) );
+SA( __is_invocable( R, int ) );
+SA( ! __is_invocable( R, int, int ) );
+
+struct S { void operator()(int, ...); };
+
+SA( ! __is_invocable( S ) );
+SA( __is_invocable( S, int ) );
+SA( __is_invocable( S, int, int ) );
+SA( __is_invocable( S, int, int, int ) );
+
+void fn1() {}
+
+SA( __is_invocable( decltype(fn1) ) );
+
+void fn2(int arr[10]);
+
+SA( __is_invocable( decltype(fn2), int[10] ) );
+SA( __is_invocable( decltype(fn2), int(&)[10] ) );
+SA( __is_invocable( decltype(fn2), int(&&)[10] ) );
+SA( ! __is_invocable( decltype(fn2), int(*)[10] ) );
+SA( ! __is_invocable( decltype(fn2), int(*&)[10] ) );
+SA( ! __is_invocable( decltype(fn2), int(*&&)[10] ) );
+SA( __is_invocable( decltype(fn2), int[] ) );
+
+auto lambda = []() {};
+
+SA( __is_invocable( decltype(lambda) ) );
+
+template <typename Func, typename... Args>
+struct can_invoke {
+ static constexpr bool value = __is_invocable( Func, Args... );
+};
+
+SA( can_invoke<decltype(lambda)>::value );
+
+struct T {
+ void func() const {}
+ int data;
+};
+
+SA( __is_invocable( decltype(&T::func)&, T& ) );
+SA( __is_invocable( decltype(&T::data)&, T& ) );
new file mode 100644
@@ -0,0 +1,139 @@
+// { dg-do compile { target c++11 } }
+// __is_invocable should handle std::reference_wrapper correctly.
+
+#include <functional>
+
+#define SA(X) static_assert((X),#X)
+
+using std::reference_wrapper;
+
+using func_type_v0 = void(*)();
+
+SA( __is_invocable( reference_wrapper<func_type_v0> ) );
+SA( ! __is_invocable( reference_wrapper<func_type_v0>, int ) );
+
+using func_type_i0 = int(*)();
+
+SA( __is_invocable( reference_wrapper<func_type_i0> ) );
+SA( ! __is_invocable( reference_wrapper<func_type_i0>, int ) );
+
+using func_type_l0 = int&(*)();
+
+SA( __is_invocable( reference_wrapper<func_type_l0> ) );
+SA( ! __is_invocable( reference_wrapper<func_type_l0(int)> ) );
+
+using func_type_ii = int(*)(int);
+
+SA( ! __is_invocable( reference_wrapper<func_type_ii> ) );
+SA( __is_invocable( reference_wrapper<func_type_ii>, int ) );
+
+using func_type_il = int(*)(int&);
+
+SA( ! __is_invocable( reference_wrapper<func_type_il> ) );
+SA( ! __is_invocable( reference_wrapper<func_type_il>, int ) );
+SA( __is_invocable( reference_wrapper<func_type_il>, int& ) );
+
+using func_type_ir = int(*)(int&&);
+
+SA( ! __is_invocable( reference_wrapper<func_type_ir> ) );
+SA( ! __is_invocable( reference_wrapper<func_type_ir>, int& ) );
+SA( __is_invocable( reference_wrapper<func_type_ir>, int ) );
+SA( __is_invocable( reference_wrapper<func_type_ir>, int&& ) );
+
+struct A { };
+
+using mem_type_i = int A::*;
+
+SA( ! __is_invocable( reference_wrapper<mem_type_i> ) );
+SA( ! __is_invocable( reference_wrapper<mem_type_i>, int ) );
+SA( ! __is_invocable( reference_wrapper<mem_type_i>, int* ) );
+SA( ! __is_invocable( reference_wrapper<mem_type_i>, int& ) );
+SA( ! __is_invocable( reference_wrapper<mem_type_i>, int&& ) );
+SA( __is_invocable( reference_wrapper<mem_type_i>, A ) );
+SA( __is_invocable( reference_wrapper<mem_type_i>, A* ) );
+SA( __is_invocable( reference_wrapper<mem_type_i>, A& ) );
+SA( __is_invocable( reference_wrapper<mem_type_i>, A&& ) );
+
+using memfun_type_i = int (A::*)();
+
+SA( ! __is_invocable( reference_wrapper<memfun_type_i> ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int* ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int& ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_i>, int&& ) );
+SA( __is_invocable( reference_wrapper<memfun_type_i>, A ) );
+SA( __is_invocable( reference_wrapper<memfun_type_i>, A* ) );
+SA( __is_invocable( reference_wrapper<memfun_type_i>, A& ) );
+SA( __is_invocable( reference_wrapper<memfun_type_i>, A&& ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_i>, const A& ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_i>, A&, int ) );
+
+using memfun_type_ic = int (A::*)() const;
+
+SA( ! __is_invocable( reference_wrapper<memfun_type_ic> ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, int ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, int& ) );
+SA( __is_invocable( reference_wrapper<memfun_type_ic>, A& ) );
+SA( __is_invocable( reference_wrapper<memfun_type_ic>, A* ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, A&, int ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, A*, int& ) );
+SA( __is_invocable( reference_wrapper<memfun_type_ic>, const A& ) );
+SA( __is_invocable( reference_wrapper<memfun_type_ic>, const A* ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, const A&, int& ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_ic>, const A*, int ) );
+
+using memfun_type_iic = int& (A::*)(int&) const;
+
+SA( ! __is_invocable( reference_wrapper<memfun_type_iic> ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, int ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, int& ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, A&, int ) );
+SA( __is_invocable( reference_wrapper<memfun_type_iic>, A&, int& ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, A*, int ) );
+SA( __is_invocable( reference_wrapper<memfun_type_iic>, A*, int& ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int ) );
+SA( ! __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int&, int ) );
+SA( __is_invocable( reference_wrapper<memfun_type_iic>, const A&, int& ) );
+SA( __is_invocable( reference_wrapper<memfun_type_iic>, const A*, int& ) );
+
+struct B {
+ int& operator()();
+ long& operator()() const;
+ bool& operator()(int);
+private:
+ void operator()(int, int);
+};
+using CB = const B;
+
+SA( __is_invocable( reference_wrapper<B> ) );
+SA( __is_invocable( reference_wrapper<B>& ) );
+SA( __is_invocable( reference_wrapper<B>&& ) );
+SA( __is_invocable( reference_wrapper<CB> ) );
+SA( __is_invocable( reference_wrapper<CB>& ) );
+SA( __is_invocable( reference_wrapper<B>, int ) );
+SA( ! __is_invocable( reference_wrapper<B>&, int, int ) );
+
+struct C : B { int& operator()() = delete; };
+using CC = const C;
+
+SA( ! __is_invocable( reference_wrapper<C> ) );
+SA( ! __is_invocable( reference_wrapper<C>& ) );
+SA( ! __is_invocable( reference_wrapper<C>&& ) );
+SA( ! __is_invocable( reference_wrapper<CC> ) );
+SA( ! __is_invocable( reference_wrapper<CC>& ) );
+
+struct D { B operator*(); };
+using CD = const D;
+
+SA( ! __is_invocable( reference_wrapper<D> ) );
+SA( ! __is_invocable( reference_wrapper<D>& ) );
+SA( ! __is_invocable( reference_wrapper<D>&& ) );
+SA( ! __is_invocable( reference_wrapper<D>* ) );
+SA( ! __is_invocable( reference_wrapper<D*> ) );
+SA( ! __is_invocable( reference_wrapper<D*>* ) );
+
+std::function<void()> fn = []() {};
+auto refwrap = std::ref(fn);
+
+SA( __is_invocable( decltype(fn) ) );
+SA( __is_invocable( decltype(refwrap) ) );
new file mode 100644
@@ -0,0 +1,51 @@
+// { dg-do compile { target c++11 } }
+// __is_invocable should handle incomplete class correctly.
+
+#define SA(X) static_assert((X),#X)
+
+struct Incomplete;
+
+SA( ! __is_invocable( Incomplete ) ); // { dg-error "incomplete type" }
+SA( ! __is_invocable( Incomplete, int ) ); // { dg-error "incomplete type" }
+
+SA( ! __is_invocable( int, Incomplete, int ) ); // { dg-error "incomplete type" }
+SA( ! __is_invocable( int, Incomplete ) ); // { dg-error "incomplete type" }
+
+SA( ! __is_invocable( Incomplete, Incomplete() ) ); // { dg-error "incomplete type" }
+SA( ! __is_invocable( Incomplete, Incomplete(int), int ) ); // { dg-error "incomplete type" }
+SA( ! __is_invocable( Incomplete, Incomplete(int, int), int, int ) ); // { dg-error "incomplete type" }
+
+SA( ! __is_invocable( Incomplete, Incomplete(), int, int ) ); // { dg-error "incomplete type" }
+
+SA( ! __is_invocable( int(Incomplete), Incomplete ) ); // { dg-error "incomplete type" }
+SA( ! __is_invocable( int(int, Incomplete), int, Incomplete ) ); // { dg-error "incomplete type" }
+SA( ! __is_invocable( int(int, Incomplete), Incomplete, int ) ); // { dg-error "incomplete type" }
+
+SA( __is_invocable( int(Incomplete&), Incomplete& ) ); // { dg-bogus "incomplete type" }
+SA( __is_invocable( int(int, Incomplete&), int, Incomplete& ) ); // { dg-bogus "incomplete type" }
+
+SA( __is_invocable( int(Incomplete&&), Incomplete&& ) ); // { dg-bogus "incomplete type" }
+SA( __is_invocable( int(int, Incomplete&&), int, Incomplete&& ) ); // { dg-bogus "incomplete type" }
+
+SA( __is_invocable( int(const Incomplete&&), const Incomplete&& ) ); // { dg-bogus "incomplete type" }
+SA( __is_invocable( int(int, const Incomplete&&), int, const Incomplete&& ) ); // { dg-bogus "incomplete type" }
+
+SA( __is_invocable( int(const Incomplete&), const Incomplete& ) ); // { dg-bogus "incomplete type" }
+SA( __is_invocable( int(int, const Incomplete&), int, const Incomplete& ) ); // { dg-bogus "incomplete type" }
+
+SA( __is_invocable( int(const Incomplete&), Incomplete& ) ); // { dg-bogus "incomplete type" }
+SA( __is_invocable( int(int, const Incomplete&), int, Incomplete& ) ); // { dg-bogus "incomplete type" }
+
+SA( __is_invocable( int Incomplete::*, const Incomplete& ) ); // { dg-bogus "incomplete type" }
+SA( ! __is_invocable( void (Incomplete::*)(long&), const Incomplete*, long& ) ); // { dg-bogus "incomplete type" }
+SA( __is_invocable( void (Incomplete::*)(long&) const, Incomplete*, long& ) ); // { dg-bogus "incomplete type" }
+
+template <typename T>
+struct Holder { T t; };
+
+SA( __is_invocable( int(Holder<Incomplete>&), Holder<Incomplete>& ) ); // { dg-bogus "incomplete type" }
+
+// Define Incomplete, which is now not incomplete.
+struct Incomplete { void operator()(); };
+
+SA( __is_invocable( Incomplete ) ); // { dg-bogus "incomplete type" }
new file mode 100644
@@ -0,0 +1,33 @@
+// { dg-do compile { target c++11 } }
+// Failed access check should be a substitution failure, not an error.
+
+#define SA(X) static_assert((X),#X)
+
+template<bool B>
+struct bool_constant { static constexpr bool value = B; };
+
+template<typename _Fn, typename... _ArgTypes>
+struct is_invocable
+: public bool_constant<__is_invocable(_Fn, _ArgTypes...)>
+{ };
+
+#if __cpp_variable_templates
+template<typename _Fn, typename... _ArgTypes>
+constexpr bool is_invocable_v = __is_invocable(_Fn, _ArgTypes...);
+#endif
+
+class Private
+{
+ void operator()() const
+ {
+ SA( ! is_invocable<Private>::value );
+#if __cpp_variable_templates
+ SA( ! is_invocable_v<Private> );
+#endif
+ }
+};
+
+SA( ! is_invocable<Private>::value );
+#if __cpp_variable_templates
+SA( ! is_invocable_v<Private> );
+#endif