Hi,
On 21/12/2017 17:04, Jason Merrill wrote:
On Wed, Dec 20, 2017 at 10:37 AM, Paolo Carlini
<paolo.carl...@oracle.com> wrote:
in this error recovery regression, after a sensible error produced by
unqualified_name_lookup_error we ICE much later when gimplify_modify_expr
encounters a corresponding error_mark_node as second argument of a
MODIFY_EXPR. I believe we have a very general error recovery weakness with
errors like unqualified_name_lookup_error and functions like
cp_parser_initializer_list returning a vec: certainly we don't want to give
up the parsing too early but then we have to cope with error_mark_nodes
filtering down and reappearing much later in the compilation. The present
bug is a rather clear example, but I have seen many others in the past: a
couple of times I even tried doing something about it, but I have yet to
figure out something worth sending to the mailing list. Anyway, here I'm
wondering if at this stage it would make sense to handle the error_mark_node
in gimplify_modify_expr - I believe we do have a couple other cases of such
late handling in the gimplifier. Tested x86_64-linux.
This seems fine, but the front end shouldn't have created such a
MODIFY_EXPR in the first place. How does this happen?
Thanks for asking: a good cure for my laziness ;)
In fact, it's an INIT_EXPR, created by build_vec_init around line #4402.
The below works for the testcase and I'm finishing regtesting it.
Alternately, only setting errors = true when init == error_mark_node,
which eventually leads anyway to build_vec_init returning
error_mark_node, also works for the testcase: it's a little lighter, so
to speak, but less explicit (setting elt_init = error_mark_node leads to
errors = true too a few lines below).
Thanks!
Paolo.
////////////////////////
/cp
2017-12-21 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/81055
* init.c (build_vec_init): Avoid building an INIT_EXPR with
error_mark_node as second argument.
/testsuite
2017-12-21 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/81055
* g++.dg/cpp0x/new2.C: New.
Index: cp/init.c
===================================================================
--- cp/init.c (revision 255946)
+++ cp/init.c (working copy)
@@ -4399,7 +4399,9 @@ build_vec_init (tree base, tree maxindex, tree ini
if (TREE_CODE (init) == TREE_LIST)
init = build_x_compound_expr_from_list (init, ELK_INIT,
complain);
- elt_init = build2 (INIT_EXPR, type, to, init);
+ elt_init = (init == error_mark_node
+ ? error_mark_node
+ : build2 (INIT_EXPR, type, to, init));
}
}
Index: testsuite/g++.dg/cpp0x/new2.C
===================================================================
--- testsuite/g++.dg/cpp0x/new2.C (nonexistent)
+++ testsuite/g++.dg/cpp0x/new2.C (working copy)
@@ -0,0 +1,4 @@
+// PR c++/81055
+// { dg-do compile { target c++11 } }
+
+int** p = new int*[1]{q}; // { dg-error "not declared" }
