On Mar 20, 2018, Jason Merrill <ja...@redhat.com> wrote:
> On Sat, Mar 17, 2018 at 8:11 AM, Alexandre Oliva <aol...@redhat.com> wrote:
>> - sorry
>> - ("cannot initialize multi-dimensional array with initializer");
> This shouldn't even be a sorry anymore
> Let's make it a hard error here.
Like this?
[PR c++/71965] silence multi-dim array init sorry without tf_error
We shouldn't substitute templates into short-circuited-out concepts
constraints, but we do, and to add insult to injury, we issue a
sorry() error when a concept that shouldn't even have been substituted
attempts to perform a multi-dimensional array initialization with a
new{} expression.
Although fixing the requirements short-circuiting is probably too
risky at this point, we can get closer to the intended effect by
silencing that sorry just as we silence other errors.
Regstrapping... Ok to install if it passes?
for gcc/cp/ChangeLog
PR c++/71965
* init.c (build_vec_init): Silence error, former sorry,
without tf_error.
for gcc/testsuite/ChangeLog
PR c++/71965
* g++.dg/concepts/pr71965.C: New.
---
gcc/cp/init.c | 19 ++++++++++++-------
gcc/testsuite/g++.dg/concepts/pr71965.C | 27 +++++++++++++++++++++++++++
2 files changed, 39 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/concepts/pr71965.C
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 9091eaa90267..5dd4b407d73f 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -4384,12 +4384,17 @@ build_vec_init (tree base, tree maxindex, tree init,
else if (TREE_CODE (type) == ARRAY_TYPE)
{
if (init && !BRACE_ENCLOSED_INITIALIZER_P (init))
- sorry
- ("cannot initialize multi-dimensional array with initializer");
- elt_init = build_vec_init (build1 (INDIRECT_REF, type, base),
- 0, init,
- explicit_value_init_p,
- 0, complain);
+ {
+ if ((complain & tf_error))
+ error ("cannot initialize multi-dimensional"
+ " array with initializer");
+ elt_init = error_mark_node;
+ }
+ else
+ elt_init = build_vec_init (build1 (INDIRECT_REF, type, base),
+ 0, init,
+ explicit_value_init_p,
+ 0, complain);
}
else if (explicit_value_init_p)
{
@@ -4449,7 +4454,7 @@ build_vec_init (tree base, tree maxindex, tree init,
}
current_stmt_tree ()->stmts_are_full_exprs_p = 1;
- if (elt_init)
+ if (elt_init && !errors)
finish_expr_stmt (elt_init);
current_stmt_tree ()->stmts_are_full_exprs_p = 0;
diff --git a/gcc/testsuite/g++.dg/concepts/pr71965.C
b/gcc/testsuite/g++.dg/concepts/pr71965.C
new file mode 100644
index 000000000000..6bfaef19211f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/pr71965.C
@@ -0,0 +1,27 @@
+// { dg-do compile { target c++14 } }
+// { dg-options "-fconcepts" }
+
+template <class T>
+concept bool Destructible() {
+ return false;
+}
+
+template <class T, class...Args>
+concept bool ConstructibleObject =
+ // Concept evaluation should short-circuit even the template
+ // substitution, so we shouldn't even substitute into the requires
+ // constraint and the unimplemented multi-dimensional new T{...}
+ // initialization. ATM we do, but as long as we don't output the
+ // sorry() message we used to for such constructs when asked not
+ // to issue errors, this shouldn't be a problem for this and
+ // similar cases.
+ Destructible<T>() && requires (Args&&...args) {
+ new T{ (Args&&)args... };
+ };
+
+int main() {
+ using T = int[2][2];
+ // GCC has not implemented initialization of multi-dimensional
+ // arrays with new{} expressions.
+ static_assert(!ConstructibleObject<T, T>);
+}
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
