Hi,
I'm trying to do something about this old PR, which I find rather
disturbing: I see what's going wrong - and shouldn't be too hard to fix,
but I'd like to have help on the appropriate way to actually do it.
We have this kind of snippet:
template<typename T> void foo() {
unsigned char s[] = "";
}
int main() {
/* removing either of the calls below makes the error disappear */
foo<char>();
foo<int>();
}
and what happens is that for the *second* instantiation of foo (the
specific types don't matter at all) we produce a bugus error message
(about a wide-string as initializer for s).
Thus we have some sort of corruption in the data structures, otherwise
two different instantiations cannot possibly affect each other.
Indeed, in digest_init_r we do something like, around line 910:
TREE_TYPE (init) = type;
which cannot be right when it does something useful, because init is a
STRING_CST here which will be used also in the other instantiations!
The analysis is confirmed by the fact that the rather heavy handed
patchlet which I'm attaching, which uses copy_node to avoid the
corruption, "works". How do we normally handle this kind of situation?
Thanks,
Paolo.
/////////////////
Index: typeck2.c
===================================================================
--- typeck2.c (revision 182776)
+++ typeck2.c (working copy)
@@ -902,7 +902,11 @@ digest_init_r (tree type, tree init, bool nested,
}
}
- TREE_TYPE (init) = type;
+ if (type != TREE_TYPE (init))
+ {
+ init = copy_node (init);
+ TREE_TYPE (init) = type;
+ }
if (TYPE_DOMAIN (type) != 0 && TREE_CONSTANT (TYPE_SIZE (type)))
{
int size = TREE_INT_CST_LOW (TYPE_SIZE (type));
