This patch benefits from the discussion of array deduction at last
week's C++ standardization committee meeting, where we clarified that we
should only try to deduce the array bound from an initializer-list if
the array bound is deducible, i.e. if it's a non-type template
parameter. We also should avoid crashing on a 0-length init-list which
would result in an invalid 0-length array.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 8fc69de2c377470b3ae9a8ebc65b0909d626d6e3
Author: Jason Merrill <ja...@redhat.com>
Date: Fri Feb 21 00:16:52 2014 -0500
DR 1591
PR c++/60051
* pt.c (unify): Only unify if deducible. Handle 0-length list.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 4cf387a..0f576a5 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -17262,14 +17262,16 @@ unify (tree tparms, tree targs, tree parm, tree arg, int strict,
explain_p);
}
- if (TREE_CODE (parm) == ARRAY_TYPE)
+ if (TREE_CODE (parm) == ARRAY_TYPE
+ && deducible_array_bound (TYPE_DOMAIN (parm)))
{
/* Also deduce from the length of the initializer list. */
tree max = size_int (CONSTRUCTOR_NELTS (arg));
tree idx = compute_array_index_type (NULL_TREE, max, tf_none);
- if (TYPE_DOMAIN (parm) != NULL_TREE)
- return unify_array_domain (tparms, targs, TYPE_DOMAIN (parm),
- idx, explain_p);
+ if (idx == error_mark_node)
+ return unify_invalid (explain_p);
+ return unify_array_domain (tparms, targs, TYPE_DOMAIN (parm),
+ idx, explain_p);
}
/* If the std::initializer_list<T> deduction worked, replace the
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist80.C b/gcc/testsuite/g++.dg/cpp0x/initlist80.C
new file mode 100644
index 0000000..7947f1f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist80.C
@@ -0,0 +1,6 @@
+// PR c++/60051
+// { dg-require-effective-target c++11 }
+
+#include <initializer_list>
+
+auto x[2] = {}; // { dg-error "" }