Patchwork C++ PATCH for c++/48319 (ICE with value-dependent call)

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Submitter Jason Merrill
Date March 29, 2011, 6:57 p.m.
Message ID <4D922B9A.3050600@redhat.com>
Download mbox | patch
Permalink /patch/88833/
State New
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Comments

Jason Merrill - March 29, 2011, 6:57 p.m.
In this testcase, we were failing to consider declval<_Args1> as 
value-dependent, even though it is due to the use of a type parameter. 
We previously just handled TEMPLATE_ID_EXPR as a normal binary 
expression and assumed that a TREE_VEC was always non-dependent.

Tested x86_64-pc-linux-gnu, applied to trunk and 4.6.
commit 877698d7630d958bfbe1e7a7a69c8a4290c486a2
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Mar 29 13:05:08 2011 -0400

    	PR c++/48319
    	* pt.c (value_dependent_expression_p): Handle TEMPLATE_ID_EXPR.

Patch

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index dfc726a..aa0901b 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -18218,6 +18218,11 @@  value_dependent_expression_p (tree expression)
 	return false;
       }
 
+    case TEMPLATE_ID_EXPR:
+      /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
+	 type-dependent.  */
+      return type_dependent_expression_p (expression);
+
     default:
       /* A constant expression is value-dependent if any subexpression is
 	 value-dependent.  */
diff --git a/gcc/testsuite/g++.dg/cpp0x/dependent1.C b/gcc/testsuite/g++.dg/cpp0x/dependent1.C
new file mode 100644
index 0000000..1ceeeaf
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/dependent1.C
@@ -0,0 +1,25 @@ 
+// PR c++/48319
+// { dg-options -std=c++0x }
+// We were failing to recognize declval<_Args1> as dependent.
+
+template<typename Tp> Tp declval() noexcept;
+
+template<typename _Tp>
+class __is_constructible_helper
+{
+  typedef char __one;
+  typedef struct { char __arr[2]; } __two;
+
+  template<typename _Tp1, typename... _Args1>
+  static decltype(_Tp1(declval<_Args1>()...), __one()) __test(int);
+
+  template<typename, typename...>
+  static __two __test(...);
+
+public:
+  static const bool __value = sizeof(__test<_Tp>(0)) == 1;
+};
+
+int main() {
+  return __is_constructible_helper<int>::__value;
+}