PR c++/92745 - bogus error when initializing array of vectors.

In r268428 I changed reshape_init_r in such a way that when it sees
a nested { } in a CONSTRUCTOR with missing braces, it just returns
the initializer:
+     else if (COMPOUND_LITERAL_P (stripped_init)
...
+         ++d->cur;
+         gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
+         return init;

But as this test shows, that's incorrect: if TYPE is an array, we need
to proceed to reshape_init_array_1 which will iterate over the array
initializers:
 6006   /* Loop until there are no more initializers.  */
 6007   for (index = 0;
 6008        d->cur != d->end && (!sized_array_p || index <= max_index_cst);
 6009        ++index)
 6010     {
and update d.cur accordingly.  In other words, when reshape_init gets

{{col[0][0], col[1][0], col[2][0], col[3][0]},
 {col[0][1], col[1][1], col[2][1], col[3][1]},
 {col[0][2], col[1][2], col[2][2], col[3][2]},
 {col[0][3], col[1][3], col[2][3], col[3][3]}}

we recurse on the first element:
  {col[0][0], col[1][0], col[2][0], col[3][0]}
and we can't just move d.cur to point to
  {col[0][1], col[1][1], col[2][1], col[3][1]}
and return; we need to iterate, so that d.cur ends up being properly
updated, and after all initializers have been seen, points to d.end.
Currently we skip the loop, wherefore we hit this:

 6502   /* Make sure all the element of the constructor were used. Otherwise,
 6503      issue an error about exceeding initializers.  */
 6504   if (d.cur != d.end)
 6505     {
 6506       if (complain & tf_error)
 6507         error ("too many initializers for %qT", type);
 6508       return error_mark_node;
 6509     }

gcc/cp/ChangeLog
2020-02-25  Marek Polacek  <polacek@redhat.com>

	PR c++/92745 - bogus error when initializing array of vectors.
	* decl.c (reshape_init_r): For a nested compound literal, do
	call reshape_init_{class,array,vector}.

gcc/testsuite/ChangeLog
2020-02-25  Marek Polacek  <polacek@redhat.com>
	    Jakub Jelinek  <jakub@redhat.com>

	PR c++/92745
	* g++.dg/cpp0x/initlist118.C: New test.
	* g++.dg/cpp0x/initlist118.C: Add -Wno-psabi -w to dg-options.

1 files changed, 6 insertions, 0 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a1fee50..b73cc56 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-25  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/92745 - bogus error when initializing array of vectors.
+	* decl.c (reshape_init_r): For a nested compound literal, do
+	call reshape_init_{class,array,vector}.
+
 2020-02-25  Jason Merrill  <jason@redhat.com>
 
 	PR c++/89917 - ICE with lambda in variadic mem-init.