[Concepts] Add diagnostics which fall under [dcl.spec.concept]p1

[nwilson]

Summary

Diagnose when the 'concept' specifier is used on a typedef or function parameter.

[hubert.reinterpretcast]

LGTM

[aaron.ballman]

LGTM!

cfe/trunk/lib/Sema/SemaDecl.cpp

if (D.getCXXScopeSpec().isSet()) {
     Previous.clear();
   }
 
   DiagnoseFunctionSpecifiers(D.getDeclSpec());
 
   if (D.getDeclSpec().isConstexprSpecified())
     Diag(D.getDeclSpec().getConstexprSpecLoc(), diag::err_invalid_constexpr)
       << 1;
+  if (D.getDeclSpec().isConceptSpecified())
+    Diag(D.getDeclSpec().getConceptSpecLoc(),
+         diag::err_concept_wrong_decl_kind);
 
   if (D.getName().Kind != UnqualifiedId::IK_Identifier) {
     Diag(D.getName().StartLocation, diag::err_typedef_not_identifier)
       << D.getName().getSourceRange();
     return nullptr;
   }
 
   TypedefDecl *NewTD = ParseTypedefDecl(S, D, TInfo->getType(), TInfo);
Decl *Sema::ActOnParamDeclarator(Scope *S, Declarator &D) {
   }
 
   if (DeclSpec::TSCS TSCS = DS.getThreadStorageClassSpec())
     Diag(DS.getThreadStorageClassSpecLoc(), diag::err_invalid_thread)
       << DeclSpec::getSpecifierName(TSCS);
   if (DS.isConstexprSpecified())
     Diag(DS.getConstexprSpecLoc(), diag::err_invalid_constexpr)
       << 0;
+  if (DS.isConceptSpecified())
+    Diag(DS.getConceptSpecLoc(), diag::err_concept_wrong_decl_kind);
 
   DiagnoseFunctionSpecifiers(DS);
 
   TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
   QualType parmDeclType = TInfo->getType();
 
   if (getLangOpts().CPlusPlus) {
     // Check that there are no default arguments inside the type of this

cfe/trunk/test/CXX/concepts-ts/dcl.dcl/dcl.spec/dcl.spec.concept/p1.cpp

 // Tag
 concept class CC1 {}; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
 concept struct CS1 {}; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
 concept union CU1 {}; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
 concept enum CE1 {}; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
 template <typename T> concept class TCC1 {}; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
 template <typename T> concept struct TCS1 {}; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
 template <typename T> concept union TCU1 {}; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
+typedef concept int CI; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
+void fpc(concept int i) {} // expected-error {{'concept' can only appear on the definition of a function template or variable template}}
 
 concept bool; // expected-error {{'concept' can only appear on the definition of a function template or variable template}}