* c.opt: Add -fno-deduce-init-list.
* pt.c (get_pattern_parm): New.
(listify): Split out from...
(listify_autos): ...here.
(unify): Deduce std::initializer_list for T.
* call.c (build_over_call): Warn about it.
From-SVN: r151867
+2009-09-18 Jason Merrill <jason@redhat.com>
+
+ * c.opt: Add -fno-deduce-init-list.
+
2009-09-18 Neil Vachharajani <nvachhar@google.com>
* value-prof.c (interesting_stringop_to_profile_p): Added output
ObjC ObjC++ Joined
-fconst-string-class=<name> Use class <name> for constant strings
+fdeduce-init-list
+C++ ObjC++ Var(flag_deduce_init_list) Init(1)
+-fno-deduce-init-list disable deduction of std::initializer_list for a template type parameter from a brace-enclosed initializer-list
+
fdefault-inline
C++ ObjC++
Inline member functions by default
+2009-09-18 Jason Merrill <jason@redhat.com>
+
+ * pt.c (get_pattern_parm): New.
+ (listify): Split out from...
+ (listify_autos): ...here.
+ (unify): Deduce std::initializer_list for T.
+ * call.c (build_over_call): Warn about it.
+
2009-09-17 Andrew Pinski <pinskia@gcc.gnu.org>
PR c++/39365
* decl.c (build_init_list_var_init): Check return value of
perform_implicit_conversion.
-2009-09-03 Jason Merrill <jason@redhat.com>
+2009-09-08 Jason Merrill <jason@redhat.com>
* class.c (currently_open_class): Make sure we're dealing with the
main variant.
&& !TREE_ADDRESSABLE (type))
conv = conv->u.next;
+ /* Warn about initializer_list deduction that isn't currently in the
+ working draft. */
+ if (cxx_dialect > cxx98
+ && flag_deduce_init_list
+ && cand->template_decl
+ && is_std_init_list (non_reference (type)))
+ {
+ tree tmpl = TI_TEMPLATE (cand->template_decl);
+ tree realparm = chain_index (j, DECL_ARGUMENTS (cand->fn));
+ tree patparm = get_pattern_parm (realparm, tmpl);
+
+ if (!is_std_init_list (non_reference (TREE_TYPE (patparm))))
+ {
+ pedwarn (input_location, 0, "deducing %qT as %qT",
+ non_reference (TREE_TYPE (patparm)),
+ non_reference (type));
+ pedwarn (input_location, 0, " in call to %q+D", cand->fn);
+ pedwarn (input_location, 0,
+ " (you can disable this with -fno-deduce-init-list)");
+ }
+ }
+
val = convert_like_with_context
(conv, VEC_index (tree, args, arg_index), fn, i - is_method,
complain);
extern int template_class_depth (tree);
extern int is_specialization_of (tree, tree);
extern bool is_specialization_of_friend (tree, tree);
+extern tree get_pattern_parm (tree, tree);
extern int comp_template_args (tree, tree);
extern tree maybe_process_partial_specialization (tree);
extern tree most_specialized_instantiation (tree);
static void append_type_to_template_for_access_check_1 (tree, tree, tree);
static hashval_t iterative_hash_template_arg (tree arg, hashval_t val);
static bool primary_template_instantiation_p (const_tree);
+static tree listify (tree);
+static tree listify_autos (tree, tree);
/* Make the current scope suitable for access checking when we are
processing T. T can be FUNCTION_DECL for instantiated function
return result;
}
+/* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
+ TMPL. We do this using DECL_PARM_INDEX, which should work even with
+ parameter packs; all parms generated from a function parameter pack will
+ have the same DECL_PARM_INDEX. */
+
+tree
+get_pattern_parm (tree parm, tree tmpl)
+{
+ tree pattern = DECL_TEMPLATE_RESULT (tmpl);
+ tree patparm;
+
+ if (DECL_ARTIFICIAL (parm))
+ {
+ for (patparm = DECL_ARGUMENTS (pattern);
+ patparm; patparm = TREE_CHAIN (patparm))
+ if (DECL_ARTIFICIAL (patparm)
+ && DECL_NAME (parm) == DECL_NAME (patparm))
+ break;
+ }
+ else
+ {
+ patparm = FUNCTION_FIRST_USER_PARM (DECL_TEMPLATE_RESULT (tmpl));
+ patparm = chain_index (DECL_PARM_INDEX (parm)-1, patparm);
+ gcc_assert (DECL_PARM_INDEX (patparm)
+ == DECL_PARM_INDEX (parm));
+ }
+
+ return patparm;
+}
+
/* Substitute ARGS into the vector or list of template arguments T. */
static tree
{
tree elt, elttype;
unsigned i;
+ tree orig_parm = parm;
+
+ /* Replace T with std::initializer_list<T> for deduction. */
+ if (TREE_CODE (parm) == TEMPLATE_TYPE_PARM
+ && flag_deduce_init_list)
+ parm = listify (parm);
if (!is_std_init_list (parm))
/* We can only deduce from an initializer list argument if the
if (unify (tparms, targs, elttype, elt, elt_strict))
return 1;
}
+
+ /* If the std::initializer_list<T> deduction worked, replace the
+ deduced A with std::initializer_list<A>. */
+ if (orig_parm != parm)
+ {
+ idx = TEMPLATE_TYPE_IDX (orig_parm);
+ targ = TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx);
+ targ = listify (targ);
+ TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx) = targ;
+ }
return 0;
}
return au;
}
-/* Replace auto in TYPE with std::initializer_list<auto>. */
+/* Given type ARG, return std::initializer_list<ARG>. */
static tree
-listify_autos (tree type, tree auto_node)
+listify (tree arg)
{
tree std_init_list = namespace_binding
(get_identifier ("initializer_list"), std_node);
tree argvec;
- tree init_auto;
if (!std_init_list || !DECL_CLASS_TEMPLATE_P (std_init_list))
{
- error ("deducing auto from brace-enclosed initializer list requires "
+ error ("deducing from brace-enclosed initializer list requires "
"#include <initializer_list>");
return error_mark_node;
}
argvec = make_tree_vec (1);
- TREE_VEC_ELT (argvec, 0) = auto_node;
- init_auto = lookup_template_class (std_init_list, argvec, NULL_TREE,
- NULL_TREE, 0, tf_warning_or_error);
+ TREE_VEC_ELT (argvec, 0) = arg;
+ return lookup_template_class (std_init_list, argvec, NULL_TREE,
+ NULL_TREE, 0, tf_warning_or_error);
+}
+
+/* Replace auto in TYPE with std::initializer_list<auto>. */
+static tree
+listify_autos (tree type, tree auto_node)
+{
+ tree init_auto = listify (auto_node);
+ tree argvec = make_tree_vec (1);
TREE_VEC_ELT (argvec, 0) = init_auto;
if (processing_template_decl)
argvec = add_to_template_args (current_template_args (), argvec);
This option is no longer useful on most targets, now that support has
been added for putting variables into BSS without making them common.
+@item -fno-deduce-init-list
+@opindex fno-deduce-init-list
+Disable deduction of a template type parameter as
+std::initializer_list from a brace-enclosed initializer list, i.e.
+
+@smallexample
+template <class T> auto forward(T t) -> decltype (realfn (t))
+@{
+ return realfn (t);
+@}
+
+void f()
+@{
+ forward(@{1,2@}); // call forward<std::initializer_list<int>>
+@}
+@end smallexample
+
+This option is present because this deduction is an extension to the
+current specification in the C++0x working draft, and there was
+some concern about potential overload resolution problems.
+
@item -ffriend-injection
@opindex ffriend-injection
Inject friend functions into the enclosing namespace, so that they are
+2009-09-18 Jason Merrill <jason@redhat.com>
+
+ * g++.dg/cpp0x/initlist-deduce.C: New.
+
2009-09-18 Janis Johnson <janis187@us.ibm.com>
* gcc.dg/dfp/dfp.exp: Also run tests in c-c++-common/dfp.
--- /dev/null
+// Test for deduction of T as std::initializer_list. This isn't currently
+// supported by the working draft, but is necessary for perfect forwarding
+// of initializer-lists to things that can take a std::initializer_list.
+
+// { dg-options -std=c++0x }
+// { dg-do run }
+
+#include <initializer_list>
+
+struct A
+{
+ A(std::initializer_list<int>) { }
+};
+
+void f (A a) { }
+
+template <class T>
+auto g (T&& t) -> decltype (f(t)) // { dg-warning "call" }
+{
+ return f(t);
+}
+
+int main()
+{
+ g({1}); // { dg-warning "deduc" }
+}