Reimplement Sema::MatchTemplateParametersToScopeSpecifier() based on

the semantic context referenced by the nested-name-specifier rather
than the syntactic form of the nested-name-specifier. The previous
incarnation was based on my complete misunderstanding of C++
[temp.expl.spec]. The latest C++0x working draft clarifies the
requirements here, and this rewrite is intended to follow that.

Along the way, improve source location information in the
diagnostics. For example, if we report that a specific type needs or
doesn't need a 'template<>' header, we dig out that type in the
nested-name-specifier and highlight its range.

Fixes: PR5907, PR9421, PR8277, PR8708, PR9482, PR9668, PR9877, and
<rdar://problem/9135379>.

llvm-svn: 131138

2 files changed, 169 insertions, 3 deletions

diff --git a/clang/test/CXX/temp/temp.spec/temp.expl.spec/examples.cpp b/clang/test/CXX/temp/temp.spec/temp.expl.spec/examples.cpp
new file mode 100644
index 00000000000..733aaee7545
--- /dev/null
+++ b/clang/test/CXX/temp/temp.spec/temp.expl.spec/examples.cpp
@@ -0,0 +1,167 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+namespace PR5907 {
+  template<typename T> struct identity { typedef T type; };
+  struct A { A(); }; 
+  identity<A>::type::A() { }
+
+  struct B { void f(); };
+  template<typename T> struct C { typedef B type; };
+  
+  void C<int>::type::f() { }
+}
+
+namespace PR9421 {
+  namespace N { template<typename T> struct S { void f(); }; }
+  typedef N::S<int> T;
+  namespace N { template<> void T::f() {} }
+}
+
+namespace PR8277 {
+  template< typename S >
+  struct C
+  {
+    template< int >
+    void F( void )
+    {
+    }
+  };
+
+  template< typename S >
+  struct D
+  {
+    typedef C< int > A;
+  };
+
+  typedef D< int >::A A;
+
+  template<>
+  template<>
+  void A::F< 0 >( void )
+  {
+  }
+}
+
+namespace PR8277b {
+  template<typename S> struct C {
+    void f();
+  };
+  template<typename S> struct D {
+    typedef C<int> A;
+  };
+  template<> void D<int>::A::f() {
+  }
+}
+
+namespace PR8708 {
+  template<typename T> struct A { 
+    template<typename U> struct B {
+      // #2
+      void f();     
+    }; 
+  };  
+
+  // #A specialize the member template for 
+  // implicit instantiation of A<int>,
+  // leaving the member template "unspecialized"
+  // (14.7.3/16). Specialization uses the syntax
+  // for explicit specialization (14.7.3/14)
+  template<> template<typename U> 
+  struct A<int>::B {
+    // #1
+    void g();
+  };  
+
+  // #1 define its function g. There is an enclosing
+  // class template, so we write template<> for each 
+  // specialized template (14.7.3/15).
+  template<> template<typename U>
+  void A<int>::B<U>::g() { }
+
+  // #2 define the unspecialized member template's
+  // f
+  template<typename T> template<typename U>
+  void A<T>::B<U>::f() { }
+
+
+  // specialize the member template again, now
+  // specializing the member too. This specializes
+  // #A
+  template<> template<>
+  struct A<int>::B<int> { 
+    // #3
+    void h();
+  };
+
+  // defines #3. There is no enclosing class template, so
+  // we write no "template<>".
+  void A<int>::B<int>::h() { }
+
+  void test() { 
+    // calls #1
+    A<int>::B<float> a; a.g(); 
+
+    // calls #2
+    A<float>::B<int> b; b.f();
+
+    // calls #3
+    A<int>::B<int> c; c.h();
+  }
+}
+
+namespace PR9482 {
+  namespace N1 {
+    template <typename T> struct S {
+      void foo() {}
+    };
+  }
+
+  namespace N2 {
+    typedef N1::S<int> X;
+  }
+
+  namespace N1 {
+    template<> void N2::X::foo() {}
+  }
+}
+
+namespace PR9668 {
+  namespace First
+  {
+    template<class T>
+    class Bar
+    {
+    protected:
+
+      static const bool static_bool;
+    };
+  }
+
+  namespace Second
+  {
+    class Foo;
+  }
+
+  typedef First::Bar<Second::Foo> Special;
+
+  namespace
+  First
+  {
+    template<>
+    const bool Special::static_bool(false);
+  }
+}
+
+namespace PR9877 {
+  template<int>
+  struct X
+  {
+    struct Y;
+  };
+
+  template<> struct X<0>::Y { static const int Z = 1; };
+  template<> struct X<1>::Y { static const int Z = 1; };
+
+  const int X<0>::Y::Z;
+  template<> const int X<1>::Y::Z; // expected-error{{extraneous 'template<>' in declaration of variable 'Z'}}
+}
diff --git a/clang/test/CXX/temp/temp.spec/temp.expl.spec/p17.cpp b/clang/test/CXX/temp/temp.spec/temp.expl.spec/p17.cpp
index 88cfc5d7c39..56231e2f725 100644
--- a/clang/test/CXX/temp/temp.spec/temp.expl.spec/p17.cpp
+++ b/clang/test/CXX/temp/temp.spec/temp.expl.spec/p17.cpp
@@ -24,12 +24,11 @@ namespace test1 {
 
   template <> class A<double> { 
   public:
-    static int foo; // expected-note{{attempt to specialize}}
+    static int foo;
     static int bar;    
   };
 
   typedef A<double> AB;
-  template <> int AB::foo = 0; // expected-error{{extraneous 'template<>'}} \
-                               // expected-error{{does not specialize}}
+  template <> int AB::foo = 0; // expected-error{{extraneous 'template<>'}}
   int AB::bar = 1;
 }