[PATCH] c++: zero_init_expr_p of dependent expression

[Patrick Palka via Gcc-patches]

This fixes a ICE coming from mangle.c:write_expression when compiling the
ranges-v3 testsuite; the added testcase is a reduced reproducer of the ICE.

Bootstrapped and regtested on x86_64-pc-linux-gnu, and also tested on the
cmcstl2, fmt and range-v3 libraries.  Does this look OK to commit?

gcc/cp/ChangeLog:

        * tree.c (zero_init_expr_p): Use uses_template_parms instead of
        dependent_type_p.

gcc/testsuite/ChangeLog:

        * g++.dg/cpp0x/dependent3.C: New test.
---
 gcc/cp/tree.c                           |  2 +-
 gcc/testsuite/g++.dg/cpp0x/dependent3.C | 28 +++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/dependent3.C

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 090c565c093..8840932dba2 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -4486,7 +4486,7 @@ bool
 zero_init_expr_p (tree t)
 {
   tree type = TREE_TYPE (t);
-  if (!type || dependent_type_p (type))
+  if (!type || uses_template_parms (type))
     return false;
   if (zero_init_p (type))
     return initializer_zerop (t);
diff --git a/gcc/testsuite/g++.dg/cpp0x/dependent3.C 
b/gcc/testsuite/g++.dg/cpp0x/dependent3.C
new file mode 100644
index 00000000000..caf7e1cd4a4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/dependent3.C
@@ -0,0 +1,28 @@
+// { dg-do compile { target c++11 } }
+
+template<typename c>
+struct d
+{
+  using e = c;
+};
+
+template<class f>
+struct g
+{
+  using h = typename d<f>::e;
+
+  template<class i, class j>
+  auto operator()(i, j k) -> decltype(h{k});
+};
+
+template<class l>
+void m()
+{
+  int a[1];
+  l{}(a, a);
+}
+
+int main()
+{
+  m<g<int *>>();
+}
-- 
2.26.2.266.ge870325ee8