DR259: Demote the pedantic error for an explicit instantiation after an

explicit specialization to a warning for C++98 mode (this is a defect report
resolution, so per our informal policy it should apply in C++98), and turn
the warning on by default for C++11 and later. In all cases where it fires, the
right thing to do is to remove the pointless explicit instantiation.

llvm-svn: 280308

3 files changed, 23 insertions, 29 deletions

diff --git a/clang/test/CXX/drs/dr2xx.cpp b/clang/test/CXX/drs/dr2xx.cpp
index 25c853590ae..7372ecb26c8 100644
--- a/clang/test/CXX/drs/dr2xx.cpp
+++ b/clang/test/CXX/drs/dr2xx.cpp
@@ -679,17 +679,13 @@ namespace dr258 { // dr258: yes
   } f; // expected-error {{abstract}}
 }
 
-namespace dr259 { // dr259: yes c++11
+namespace dr259 { // dr259: 4.0
   template<typename T> struct A {};
   template struct A<int>; // expected-note {{previous}}
   template struct A<int>; // expected-error {{duplicate explicit instantiation}}
 
-  // FIXME: We only apply this DR in C++11 mode.
-  template<> struct A<float>;
-  template struct A<float>;
-#if __cplusplus < 201103L
-  // expected-error@-2 {{extension}} expected-note@-3 {{here}}
-#endif
+  template<> struct A<float>; // expected-note {{previous}}
+  template struct A<float>; // expected-warning {{has no effect}}
 
   template struct A<char>; // expected-note {{here}}
   template<> struct A<char>; // expected-error {{explicit specialization of 'dr259::A<char>' after instantiation}}
@@ -702,11 +698,8 @@ namespace dr259 { // dr259: yes c++11
   template<typename T> struct B; // expected-note {{here}}
   template struct B<int>; // expected-error {{undefined}}
 
-  template<> struct B<float>;
-  template struct B<float>;
-#if __cplusplus < 201103L
-  // expected-error@-2 {{extension}} expected-note@-3 {{here}}
-#endif
+  template<> struct B<float>; // expected-note {{previous}}
+  template struct B<float>; // expected-warning {{has no effect}}
 }
 
 // FIXME: When dr260 is resolved, also add tests for DR507.
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
index d12feeff0bb..1af47a0ed56 100644
--- a/clang/test/CXX/temp/temp.spec/temp.expl.spec/examples.cpp
+++ b/clang/test/CXX/temp/temp.spec/temp.expl.spec/examples.cpp
@@ -223,8 +223,8 @@ namespace spec_vs_expl_inst {
 
   namespace SID {
     template <typename STRING_TYPE> class BasicStringPiece;
-    template <> class BasicStringPiece<int> { };
-    template class BasicStringPiece<int>;  // expected-note {{explicit instantiation definition is here}}
+    template <> class BasicStringPiece<int> { }; // expected-note {{previous template specialization is here}}
+    template class BasicStringPiece<int>;  // expected-note {{explicit instantiation definition is here}} expected-warning {{has no effect}}
     extern template class BasicStringPiece<int>;  // expected-error {{explicit instantiation declaration (with 'extern') follows explicit instantiation definition (without 'extern')}}
   }
 
@@ -252,8 +252,8 @@ namespace spec_vs_expl_inst {
   namespace DSI {
     template <typename STRING_TYPE> class BasicStringPiece;  // expected-note {{template is declared here}}
     extern template class BasicStringPiece<int>;  // expected-error {{explicit instantiation of undefined template 'spec_vs_expl_inst::DSI::BasicStringPiece<int>'}}
-    template <> class BasicStringPiece<int> { };
-    template class BasicStringPiece<int>;
+    template <> class BasicStringPiece<int> { }; // expected-note {{previous}}
+    template class BasicStringPiece<int>; // expected-warning {{has no effect}}
   }
 
   // The same again, with a defined template class.
@@ -267,8 +267,8 @@ namespace spec_vs_expl_inst {
 
   namespace SID_WithDefinedTemplate {
     template <typename STRING_TYPE> class BasicStringPiece {};
-    template <> class BasicStringPiece<int> { };
-    template class BasicStringPiece<int>;  // expected-note {{explicit instantiation definition is here}}
+    template <> class BasicStringPiece<int> { }; // expected-note {{previous}}
+    template class BasicStringPiece<int>;  // expected-note {{explicit instantiation definition is here}} expected-warning {{has no effect}}
     extern template class BasicStringPiece<int>;  // expected-error {{explicit instantiation declaration (with 'extern') follows explicit instantiation definition (without 'extern')}}
   }
 
@@ -304,15 +304,15 @@ namespace spec_vs_expl_inst {
 
   namespace SII_WithDefinedTemplate {
     template <typename STRING_TYPE> class BasicStringPiece {};
-    template <> class BasicStringPiece<int> { };
-    template class BasicStringPiece<int>;  // expected-note {{previous explicit instantiation is here}}
+    template <> class BasicStringPiece<int> { }; // expected-note {{previous}}
+    template class BasicStringPiece<int>;  // expected-note {{previous explicit instantiation is here}} expected-warning {{has no effect}}
     template class BasicStringPiece<int>;  // expected-error {{duplicate explicit instantiation of 'BasicStringPiece<int>'}}
   }
 
   namespace SIS {
     template <typename STRING_TYPE> class BasicStringPiece;
-    template <> class BasicStringPiece<int> { };  // expected-note {{previous definition is here}}
-    template class BasicStringPiece<int>;
+    template <> class BasicStringPiece<int> { };  // expected-note {{previous definition is here}} expected-note {{previous}}
+    template class BasicStringPiece<int>; // expected-warning {{has no effect}}
     template <> class BasicStringPiece<int> { };  // expected-error {{redefinition of 'spec_vs_expl_inst::SIS::BasicStringPiece<int>'}}
   }
 
diff --git a/clang/test/CXX/temp/temp.spec/temp.explicit/p4.cpp b/clang/test/CXX/temp/temp.spec/temp.explicit/p4.cpp
index 09c428e01df..0a8a0ce9ff1 100644
--- a/clang/test/CXX/temp/temp.spec/temp.explicit/p4.cpp
+++ b/clang/test/CXX/temp/temp.spec/temp.explicit/p4.cpp
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -pedantic %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
 
 template<typename T> void f0(T); // expected-note{{here}}
 template void f0(int); // expected-error{{explicit instantiation of undefined function template}}
@@ -17,19 +18,19 @@ template void X0<int>::f1(); // expected-error{{explicit instantiation of undefi
 template int X0<int>::value; // expected-error{{explicit instantiation of undefined static data member}}
 
 template<> void f0(long); // expected-note{{previous template specialization is here}}
-template void f0(long); // expected-warning{{explicit instantiation of 'f0<long>' that occurs after an explicit specialization will be ignored}}
+template void f0(long); // expected-warning{{explicit instantiation of 'f0<long>' that occurs after an explicit specialization has no effect}}
 
 template<> void X0<long>::f1(); // expected-note{{previous template specialization is here}}
-template void X0<long>::f1(); // expected-warning{{explicit instantiation of 'f1' that occurs after an explicit specialization will be ignored}}
+template void X0<long>::f1(); // expected-warning{{explicit instantiation of 'f1' that occurs after an explicit specialization has no effect}}
 
 template<> struct X0<long>::Inner; // expected-note{{previous template specialization is here}}
-template struct X0<long>::Inner; // expected-warning{{explicit instantiation of 'Inner' that occurs after an explicit specialization will be ignored}}
+template struct X0<long>::Inner; // expected-warning{{explicit instantiation of 'Inner' that occurs after an explicit specialization has no effect}}
 
 template<> long X0<long>::value; // expected-note{{previous template specialization is here}}
-template long X0<long>::value; // expected-warning{{explicit instantiation of 'value' that occurs after an explicit specialization will be ignored}}
+template long X0<long>::value; // expected-warning{{explicit instantiation of 'value' that occurs after an explicit specialization has no effect}}
 
 template<> struct X0<double>; // expected-note{{previous template specialization is here}}
-template struct X0<double>; // expected-warning{{explicit instantiation of 'X0<double>' that occurs after an explicit specialization will be ignored}}
+template struct X0<double>; // expected-warning{{explicit instantiation of 'X0<double>' that occurs after an explicit specialization has no effect}}
 
 // PR 6458
 namespace test0 {
@@ -43,6 +44,6 @@ namespace test0 {
     // inappropriately instantiating this template.
     void *ptr = x;
   }
-  extern template class foo<char>; // expected-warning {{extern templates are a C++11 extension}}
+  extern template class foo<char>; // expected-warning 0-1{{extern templates are a C++11 extension}}
   template class foo<char>;
 }