[gcc/devel/c++-modules] c++: Fix ICE with omitted template args [PR93956].

[Nathan Sidwell]

https://gcc.gnu.org/g:df15a82804e1f7f4a7432670b33387779de46549

commit df15a82804e1f7f4a7432670b33387779de46549
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Mar 10 17:51:46 2020 -0400

    c++: Fix ICE with omitted template args [PR93956].
    
    reshape_init only wants to work on BRACE_ENCLOSED_INITIALIZER_P, i.e. raw
    initializer lists, and here was getting a CONSTRUCTOR that had already been
    processed for type A<int>.  maybe_aggr_guide should also use that test.
    
    gcc/cp/ChangeLog
    2020-03-10  Jason Merrill  <jason@redhat.com>
    
            PR c++/93956
            * pt.c (maybe_aggr_guide): Check BRACE_ENCLOSED_INITIALIZER_P.

Diff:
---
 gcc/cp/ChangeLog                               | 5 +++++
 gcc/cp/pt.c                                    | 2 +-
 gcc/testsuite/g++.dg/cpp1z/class-deduction70.C | 7 +++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index e62aefde0c7..b60b1ecc604 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-10  Jason Merrill  <jason@redhat.com>
+
+	PR c++/93956
+	* pt.c (maybe_aggr_guide): Check BRACE_ENCLOSED_INITIALIZER_P.
+
 2020-03-10  Jason Merrill  <jason@redhat.com>
 
 	PR c++/93922
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 49ee3920049..179716b5680 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -28182,7 +28182,7 @@ maybe_aggr_guide (tree tmpl, tree init, vec<tree,va_gc> *args)
   tsubst_flags_t complain = tf_none;
 
   tree parms = NULL_TREE;
-  if (TREE_CODE (init) == CONSTRUCTOR)
+  if (BRACE_ENCLOSED_INITIALIZER_P (init))
     {
       init = reshape_init (type, init, complain);
       if (init == error_mark_node)
diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction70.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction70.C
new file mode 100644
index 00000000000..f14bdf0b8ec
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction70.C
@@ -0,0 +1,7 @@
+// PR c++/93596
+
+template <typename> struct A {};
+template <typename> struct B {};
+template <typename> struct C {
+  void foo () { B a = A<int> { foo }; } // { dg-error "" }
+};