On 3/21/19 4:51 PM, Marek Polacek wrote:
This is a crash in digest_init_r -- we encounter
/* "If T is a class type and the initializer list has a single
element of type cv U, where U is T or a class derived from T,
the object is initialized from that element." */
if (flag_checking
&& cxx_dialect >= cxx11
&& BRACE_ENCLOSED_INITIALIZER_P (stripped_init)
&& CONSTRUCTOR_NELTS (stripped_init) == 1
&& ((CLASS_TYPE_P (type) && !CLASSTYPE_NON_AGGREGATE (type))
|| VECTOR_TYPE_P (type)))
{
tree elt = CONSTRUCTOR_ELT (stripped_init, 0)->value;
if (reference_related_p (type, TREE_TYPE (elt)))
/* We should have fixed this in reshape_init. */
gcc_unreachable ();
}
As the comment suggests, we have code to fix this up in reshape_init_r:
/* "If T is a class type and the initializer list has a single element of
type cv U, where U is T or a class derived from T, the object is
initialized from that element." Even if T is an aggregate. */
if (cxx_dialect >= cxx11 && (CLASS_TYPE_P (type) || VECTOR_TYPE_P (type))
&& first_initializer_p
&& d->end - d->cur == 1
&& reference_related_p (type, TREE_TYPE (init)))
{
d->cur++;
return init;
}
but in this case this didn't work, because reshape_init_class always creates
a fresh CONSTRUCTOR.
But we hit that code before reshape_init_class, why didn't it work?
As of C++17, aggregates can have bases
Does it matter whether BB is a base or a member?
+ B b10 = {{B{42}}};
+ B b11 = {{B{{42}}}};
+ B b12 = {{B{{{42}}}}};
These look ill-formed to me: too many braces around the B value.
Looks like the original testcase had the same problem. So I think this
is ice-on-invalid.
Jason
