Improve the semantic checking for explicit instantiations of

templates. In particular:
  - An explicit instantiation can follow an implicit instantiation (we
  were improperly diagnosing this as an error, previously).
  - In C++0x, an explicit instantiation that follows an explicit
  specialization of the same template specialization is ignored. In
  C++98, we just emit an extension warning.
  - In C++0x, an explicit instantiation must be in a namespace
  enclosing the original template. C++98 has no such requirement.

Also, fixed a longstanding FIXME regarding the integral type that is
used for the size of a constant array type when it is being instantiated.

llvm-svn: 71689

2 files changed, 29 insertions, 5 deletions

diff --git a/clang/test/SemaTemplate/temp_explicit.cpp b/clang/test/SemaTemplate/temp_explicit.cpp
index 527532cfa9b..b6009bd9c16 100644
--- a/clang/test/SemaTemplate/temp_explicit.cpp
+++ b/clang/test/SemaTemplate/temp_explicit.cpp
@@ -1,4 +1,4 @@
-// RUN: clang-cc -fsyntax-only -verify %s
+// RUN: clang-cc -fsyntax-only -verify -pedantic %s
 //
 // Tests explicit instantiation of templates.
 template<typename T, typename U = T> class X0 { };
@@ -24,13 +24,13 @@ template class X0<double> { }; // expected-error{{explicit specialization}}
 
 // Check for explicit instantiations that come after other kinds of
 // instantiations or declarations.
-template class X0<int, int>; // expected-error{{after}}
+template class X0<int, int>; // expected-error{{duplicate}}
 
 template<> class X0<char> { }; // expected-note{{previous}}
-template class X0<char>; // expected-error{{after}}
+template class X0<char>; // expected-warning{{ignored}}
 
-void foo(X0<short>) { } // expected-note{{previous}}
-template class X0<short>;  // expected-error{{after}}
+void foo(X0<short>) { }
+template class X0<short>;
 
 // Check that explicit instantiations actually produce definitions. We
 // determine whether this happens by placing semantic errors in the
diff --git a/clang/test/SemaTemplate/temp_explicit_cxx0x.cpp b/clang/test/SemaTemplate/temp_explicit_cxx0x.cpp
new file mode 100644
index 00000000000..7045afc3032
--- /dev/null
+++ b/clang/test/SemaTemplate/temp_explicit_cxx0x.cpp
@@ -0,0 +1,24 @@
+// RUN: clang-cc -fsyntax-only -std=c++0x -verify %s
+namespace N1 {
+
+  template<typename T> struct X0 { }; // expected-note{{here}}
+
+  namespace Inner {
+    template<typename T> struct X1 { };
+  }
+
+  template struct X0<int>;
+  template struct Inner::X1<int>;
+}
+
+template<typename T> struct X2 { }; // expected-note{{here}}
+
+template struct ::N1::Inner::X1<float>;
+
+namespace N2 {
+  using namespace N1;
+
+  template struct X0<double>; // expected-error{{not in a namespace enclosing}}
+
+  template struct X2<float>; // expected-error{{at global scope}}
+}