diff options
| -rw-r--r-- | gcc/cp/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/cp/pt.c | 18 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp1z/class-deduction42.C | 19 |
3 files changed, 43 insertions, 0 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index b2df1ef..9e763ae 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,9 @@ +2017-07-26 Jason Merrill <jason@redhat.com> + + P0702R1 - List deduction of vector. + * pt.c (do_class_deduction): Special-case deduction from a single + element of related type. + 2017-07-26 Leonid Koppel <lkoppel@uwaterloo.ca> PR c++/67054 - Inherited ctor with non-default-constructible members diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index bb32353..173ec3f 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -25331,6 +25331,24 @@ do_class_deduction (tree ptype, tree tmpl, tree init, int flags, else if (BRACE_ENCLOSED_INITIALIZER_P (init)) { try_list_ctor = TYPE_HAS_LIST_CTOR (type); + if (try_list_ctor && CONSTRUCTOR_NELTS (init) == 1) + { + /* As an exception, the first phase in 16.3.1.7 (considering the + initializer list as a single argument) is omitted if the + initializer list consists of a single expression of type cv U, + where U is a specialization of C or a class derived from a + specialization of C. */ + tree elt = CONSTRUCTOR_ELT (init, 0)->value; + tree etype = TREE_TYPE (elt); + + tree tparms = INNERMOST_TEMPLATE_PARMS (DECL_TEMPLATE_PARMS (tmpl)); + tree targs = make_tree_vec (TREE_VEC_LENGTH (tparms)); + int err = unify (tparms, targs, type, etype, + UNIFY_ALLOW_DERIVED, /*explain*/false); + if (err == 0) + try_list_ctor = false; + ggc_free (targs); + } if (try_list_ctor || is_std_init_list (type)) args = make_tree_vector_single (init); else diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction42.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction42.C new file mode 100644 index 0000000..8217fd4 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction42.C @@ -0,0 +1,19 @@ +// { dg-options -std=c++1z } + +#include <initializer_list> + +template <class,class> struct same; +template <class T> struct same<T,T> { }; + +template <class T> +struct A +{ + A(const A&); + A(std::initializer_list<T>); +}; + +A a { 1 }; +A b { a }; + +same<decltype (a), decltype (b)> s; + |