From: Douglas Gregor <dgregor@apple.com>
Date: Thu, 29 Apr 2010 06:31:36 +0000 (+0000)
Subject: When performing partial ordering of class template partial
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=516e6e09821a61e8975c787e189949723249e7c5;p=clang

When performing partial ordering of class template partial
specializations, substitute the deduced template arguments and check
the resulting substitution before concluding that template argument
deduction succeeds. This marvelous little fix makes a bunch of
Boost.Spirit tests start working.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@102601 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 031209235c..2bb97eba11 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -2384,7 +2384,11 @@ Sema::getMoreSpecializedPartialSpecialization(
                                                                Info,
                                                                Deduced,
                                                                0);
-
+  if (Better1)
+    Better1 = !::FinishTemplateArgumentDeduction(*this, PS2, 
+                                                 PS1->getTemplateArgs(), 
+                                                 Deduced, Info);
+  
   // Determine whether PS2 is at least as specialized as PS1
   Deduced.clear();
   Deduced.resize(PS1->getTemplateParameters()->size());
@@ -2395,6 +2399,10 @@ Sema::getMoreSpecializedPartialSpecialization(
                                                                Info,
                                                                Deduced,
                                                                0);
+  if (Better2)
+    Better2 = !::FinishTemplateArgumentDeduction(*this, PS1, 
+                                                 PS2->getTemplateArgs(), 
+                                                 Deduced, Info);
   
   if (Better1 == Better2)
     return 0;
diff --git a/test/CXX/temp/temp.decls/temp.class.spec/temp.class.order/p2.cpp b/test/CXX/temp/temp.decls/temp.class.spec/temp.class.order/p2.cpp
index e344eedfd6..97457ea213 100644
--- a/test/CXX/temp/temp.decls/temp.class.spec/temp.class.order/p2.cpp
+++ b/test/CXX/temp/temp.decls/temp.class.spec/temp.class.order/p2.cpp
@@ -14,3 +14,35 @@ template<int I> struct X<I, I, int> {
 int array0[X<0, 0, float>::value == 0? 1 : -1];
 int array1[X<0, 1, int>::value == 1? 1 : -1];
 int array2[X<0, 0, int>::value == 2? 1 : -1];
+
+namespace DependentSubstPartialOrdering {
+  template<typename T, typename U = void, typename V = void>
+  struct X { 
+    static const unsigned value = 1;
+  };
+
+  template<typename T, typename U>
+  struct X<T, U, typename T::is_b> {
+    static const unsigned value = 2;
+  };
+
+  template<typename T>
+  struct X<T, typename T::is_a, typename T::is_b> {
+    static const unsigned value = 3;
+  };
+
+  struct X1 { };
+
+  struct X2 { 
+    typedef void is_b;
+  };
+
+  struct X3 {
+    typedef void is_a;
+    typedef void is_b;
+  };
+
+  int check_X1[X<X1, void, void>::value == 1? 1 : -1];
+  int check_X2[X<X2, void, void>::value == 2? 1 : -1];
+  int check_X3[X<X3, void, void>::value == 3? 1 : -1];
+}