[Concepts] Implement subsection [dcl.spec.concept]p7 of the Concepts TS

Summary: A program shall not declare an explicit instantiation (14.8.2), an explicit specialization (14.8.3), or a partial specialization of a concept definition.

Reviewers: rsmith, hubert.reinterpretcast, faisalv, aaron.ballman

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D18221

llvm-svn: 265868

1 files changed, 28 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index fdb7d762d29..d840e426d7a 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -6920,6 +6920,15 @@ bool Sema::CheckFunctionTemplateSpecialization(
   // Ignore access information;  it doesn't figure into redeclaration checking.
   FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
 
+  // C++ Concepts TS [dcl.spec.concept]p7: A program shall not declare [...]
+  // an explicit specialization (14.8.3) [...] of a concept definition.
+  if (Specialization->getPrimaryTemplate()->isConcept()) {
+    Diag(FD->getLocation(), diag::err_concept_specialized)
+        << 0 /*function*/ << 1 /*explicitly specialized*/;
+    Diag(Specialization->getLocation(), diag::note_previous_declaration);
+    return true;
+  }
+
   FunctionTemplateSpecializationInfo *SpecInfo
     = Specialization->getTemplateSpecializationInfo();
   assert(SpecInfo && "Function template specialization info missing?");
@@ -7774,6 +7783,15 @@ DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
         return true;
       }
 
+      // C++ Concepts TS [dcl.spec.concept]p7: A program shall not declare an
+      // explicit instantiation (14.8.2) [...] of a concept definition.
+      if (PrevTemplate->isConcept()) {
+        Diag(D.getIdentifierLoc(), diag::err_concept_specialized)
+            << 1 /*variable*/ << 0 /*explicitly instantiated*/;
+        Diag(PrevTemplate->getLocation(), diag::note_previous_declaration);
+        return true;
+      }
+
       // Translate the parser's template argument list into our AST format.
       TemplateArgumentListInfo TemplateArgs =
           makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
@@ -7988,6 +8006,16 @@ DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
          diag::ext_explicit_instantiation_without_qualified_id)
     << Specialization << D.getCXXScopeSpec().getRange();
 
+  // C++ Concepts TS [dcl.spec.concept]p7: A program shall not declare an
+  // explicit instantiation (14.8.2) [...] of a concept definition.
+  if (FunTmpl && FunTmpl->isConcept() &&
+      !D.getDeclSpec().isConceptSpecified()) {
+    Diag(D.getIdentifierLoc(), diag::err_concept_specialized)
+        << 0 /*function*/ << 0 /*explicitly instantiated*/;
+    Diag(FunTmpl->getLocation(), diag::note_previous_declaration);
+    return true;
+  }
+
   CheckExplicitInstantiationScope(*this,
                    FunTmpl? (NamedDecl *)FunTmpl
                           : Specialization->getInstantiatedFromMemberFunction(),