On Fri, May 3, 2024 at 12:38 PM Jason Merrill <ja...@redhat.com> wrote:
>
> On 5/2/24 23:25, Ken Matsui wrote:
> > Addressed Jason's review comments. Ok for trunk?
> >
> > -- >8 --
> >
> > 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.
> > * cp-tree.h (build_invoke): New function.
> > * method.cc (build_invoke): New function.
> >
> > 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 <kmat...@gcc.gnu.org>
> > ---
> > gcc/cp/constraint.cc | 6 +
> > gcc/cp/cp-trait.def | 1 +
> > gcc/cp/cp-tree.h | 2 +
> > gcc/cp/method.cc | 138 +++++++++
> > gcc/cp/semantics.cc | 5 +
> > gcc/testsuite/g++.dg/ext/has-builtin-1.C | 3 +
> > gcc/testsuite/g++.dg/ext/is_invocable1.C | 349 +++++++++++++++++++++++
> > 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 +++
> > 10 files changed, 727 insertions(+)
> > 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 c28d7bf428e..6d14ef7dcc7 100644
> > --- a/gcc/cp/constraint.cc
> > +++ b/gcc/cp/constraint.cc
> > @@ -3792,6 +3792,12 @@ 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 b1c875a6e7d..4e420d5390a 100644
> > --- a/gcc/cp/cp-trait.def
> > +++ b/gcc/cp/cp-trait.def
> > @@ -75,6 +75,7 @@ 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/cp-tree.h b/gcc/cp/cp-tree.h
> > index 1938ada0268..83dc20e1130 100644
> > --- a/gcc/cp/cp-tree.h
> > +++ b/gcc/cp/cp-tree.h
> > @@ -7338,6 +7338,8 @@ extern tree get_copy_assign
> > (tree);
> > extern tree get_default_ctor (tree);
> > extern tree get_dtor (tree,
> > tsubst_flags_t);
> > extern tree build_stub_object (tree);
> > +extern tree build_invoke (tree, const_tree,
> > + tsubst_flags_t);
> > extern tree strip_inheriting_ctors (tree);
> > extern tree inherited_ctor_binfo (tree);
> > extern bool base_ctor_omit_inherited_parms (tree);
> > diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
> > index 08a3d34fb01..6bd590707b0 100644
> > --- a/gcc/cp/method.cc
> > +++ b/gcc/cp/method.cc
> > @@ -1928,6 +1928,144 @@ build_trait_object (tree type)
> > return build_stub_object (type);
> > }
> >
> > +/* [func.require] Build an expression of INVOKE(FN_TYPE, ARG_TYPES...).
> > If the
> > + given is not invocable, returns error_mark_node. */
> > +
> > +tree
> > +build_invoke (tree fn_type, const_tree arg_types, tsubst_flags_t complain)
> > +{
> > + if (error_operand_p (fn_type) || error_operand_p (arg_types))
> > + return error_mark_node;
> > +
> > + gcc_assert (TYPE_P (fn_type));
> > + 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);
> > +
> > + /* INVOKE 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)
> > + {
> > + if (complain & tf_error)
> > + error ("pointer to data member type %qT can only be invoked with "
> > + "one argument", fn_type);
> > + return error_mark_node;
> > + }
> > +
> > + if (is_ptrmemfunc && TREE_VEC_LENGTH (arg_types) == 0)
> > + {
> > + if (complain & tf_error)
> > + error ("pointer to member function type %qT must be invoked with "
> > + "at least one argument", fn_type);
> > + return error_mark_node;
> > + }
> > +
> > + /* Construct an expression of a pointer to member. */
> > + tree ptrmem_expr;
> > + if (is_ptrdatamem || is_ptrmemfunc)
> > + {
> > + tree datum_type = TREE_VEC_ELT (arg_types, 0);
> > +
> > + /* datum must be a class type or a reference/pointer to a class
> > type. */
> > + if (!(CLASS_TYPE_P (datum_type)
> > + || ((TYPE_REF_P (datum_type) || POINTER_TYPE_P (datum_type))
> > + && CLASS_TYPE_P (TREE_TYPE (datum_type)))))
> > + {
> > + if (complain & tf_error)
> > + error ("first argument type %qT of a pointer to member must be "
> > + "a class type or a reference/pointer to a class type",
> > + datum_type);
> > + return error_mark_node;
> > + }
> > +
> > + if (TYPE_REF_P (datum_type))
> > + datum_type = TREE_TYPE (datum_type);
>
> Unfortunately, stripping the reference here...
>
> > + bool datum_is_refwrap = false;
> > + if (CLASS_TYPE_P (datum_type))
> > + {
> > + /* 1.2 & 1.5: Handle std::reference_wrapper. */
> > + tree datum_decl = TYPE_NAME (TYPE_MAIN_VARIANT (datum_type));
> > + if (decl_in_std_namespace_p (datum_decl))
> > + {
> > + const_tree name = DECL_NAME (datum_decl);
> > + if (name && (id_equal (name, "reference_wrapper")))
> > + {
> > + /* Retrieve T from std::reference_wrapper<T>,
> > + i.e., decltype(datum.get()). */
> > + datum_type = TREE_VEC_ELT (TYPE_TI_ARGS (datum_type), 0);
> > + datum_is_refwrap = true;
> > + }
> > + }
> > + }
> > +
> > + tree ptrmem_class_type = TYPE_PTRMEM_CLASS_TYPE (fn_type);
> > + const bool ptrmem_is_same_or_base_of_datum =
> > + (same_type_p (ptrmem_class_type, datum_type)
> > + || (NON_UNION_CLASS_TYPE_P (ptrmem_class_type)
> > + && NON_UNION_CLASS_TYPE_P (datum_type)
> > + && (same_type_ignoring_top_level_qualifiers_p (ptrmem_class_type,
> > + datum_type)
> > + || DERIVED_FROM_P (ptrmem_class_type, datum_type))));
> > +
> > + tree datum_expr = build_trait_object (datum_type);
>
> ...and then using the result for build_trait_object, loses the
> difference between lvalue and rvalue references.
>
> It should be enough to move this line up before stripping the reference.
>
> And then you could just
>
> datum_type = TREE_TYPE (datum_expr);
>
> since build_trait_object will have done a convert_from_reference.
Oooh, thank you so much!
>
> > + if (!ptrmem_is_same_or_base_of_datum && !datum_is_refwrap)
> > + /* 1.3 & 1.6: Try to dereference datum_expr. */
> > + datum_expr = build_x_indirect_ref (UNKNOWN_LOCATION, datum_expr,
> > + RO_UNARY_STAR, NULL_TREE,
> > complain);
> > + /* 1.1, 1.2, 1.4, & 1.5: Otherwise. */
> > +
> > + tree fn_expr = build_trait_object (fn_type);
> > + ptrmem_expr = build_m_component_ref (datum_expr, fn_expr, complain);
> > +
> > + if (error_operand_p (ptrmem_expr))
> > + return error_mark_node;
> > +
> > + if (is_ptrdatamem)
> > + return ptrmem_expr;
> > + }
> > +
> > + /* Construct expressions for arguments to INVOKE. For a pointer to
> > member
> > + function, the first argument, which is the object, is not arguments to
> > + the function. */
> > + releasing_vec args;
> > + 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);
> > + }
> > +
> > + tree invoke_expr;
> > + if (is_ptrmemfunc)
> > + invoke_expr = build_offset_ref_call_from_tree (ptrmem_expr, &args,
> > + complain);
> > + else /* 1.7. */
> > + invoke_expr = finish_call_expr (build_trait_object (fn_type), &args,
> > false,
> > + false, complain);
> > + return invoke_expr;
> > +}
> > +
> > /* Determine which function will be called when looking up NAME in TYPE,
> > called with a single ARGTYPE argument, or no argument if ARGTYPE is
> > null. FLAGS and COMPLAIN are as for build_new_method_call.
> > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> > index a293e0fc23e..55c2ec4b5b1 100644
> > --- a/gcc/cp/semantics.cc
> > +++ b/gcc/cp/semantics.cc
> > @@ -12561,6 +12561,9 @@ 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 !error_operand_p (build_invoke (type1, type2, tf_none));
> > +
> > case CPTK_IS_LAYOUT_COMPATIBLE:
> > return layout_compatible_type_p (type1, type2);
> >
> > @@ -12719,6 +12722,7 @@ same_type_ref_bind_p (cp_trait_kind kind, tree
> > type1, tree type2)
> > case CPTK_IS_CONSTRUCTIBLE:
> > case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > case CPTK_IS_TRIVIALLY_CONSTRUCTIBLE:
> > + case CPTK_IS_INVOCABLE:
> > case CPTK_REF_CONSTRUCTS_FROM_TEMPORARY:
> > case CPTK_REF_CONVERTS_FROM_TEMPORARY:
> > to = type1;
> > @@ -12821,6 +12825,7 @@ finish_trait_expr (location_t loc, cp_trait_kind
> > kind, tree type1, tree type2)
> >
> > case CPTK_IS_CONSTRUCTIBLE:
> > case CPTK_IS_CONVERTIBLE:
> > + case CPTK_IS_INVOCABLE:
> > case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > case CPTK_IS_NOTHROW_CONVERTIBLE:
> > case CPTK_IS_TRIVIALLY_CONSTRUCTIBLE:
> > diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > index bcaa56a7bc5..d1c66267855 100644
> > --- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > +++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > @@ -107,6 +107,9 @@
> > #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..d21ae1d1958
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/is_invocable1.C
> > @@ -0,0 +1,349 @@
> > +// { 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& ) );
> > +
> > +struct U { };
> > +struct V : U { U& operator*() = delete; };
> > +SA( __is_invocable( int U::*, V ) );
> > +
> > +struct W : private U { U& operator*(); };
> > +SA( ! __is_invocable( int U::*, W ) );
> > +
> > +struct X { int m; };
> > +struct Y { X& operator*(); };
> > +struct Z : Y { };
> > +SA( __is_invocable(int X::*, Z) );
> > 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..8699b0a53ca
> > --- /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
>
