[CONCEPTS] Add concept to VarDecl and diagnostic for uninitialized variable concept

Summary: Add IsConcept bit to VarDecl::NonParmVarDeclBitfields and associated isConcept/setConcept member functions. Set IsConcept to true when 'concept' specifier is in variable declaration. Create diagnostic when variable concept is not initialized.

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

Subscribers: aemerson, cfe-commits

Differential Revision: http://reviews.llvm.org/D11600

llvm-svn: 243876

1 files changed, 12 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 9f499de0843..962610c1ce5 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5855,6 +5855,9 @@ Sema::ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
 
     if (D.getDeclSpec().isConstexprSpecified())
       NewVD->setConstexpr(true);
+
+    if (D.getDeclSpec().isConceptSpecified())
+      NewVD->setConcept(true);
   }
 
   // Set the lexical context. If the declarator has a C++ scope specifier, the
@@ -9407,6 +9410,15 @@ void Sema::ActOnUninitializedDecl(Decl *RealDecl,
       return;
     }
 
+    // C++ Concepts TS [dcl.spec.concept]p1: [...]  A variable template
+    // definition having the concept specifier is called a variable concept. A
+    // concept definition refers to [...] a variable concept and its initializer.
+    if (Var->isConcept()) {
+      Diag(Var->getLocation(), diag::err_var_concept_not_initialized);
+      Var->setInvalidDecl();
+      return;
+    }
+
     // OpenCL v1.1 s6.5.3: variables declared in the constant address space must
     // be initialized.
     if (!Var->isInvalidDecl() &&