Rework parsing of pure-specifiers. Perform the grammar matching and
disambiguation in the parser rather than trying to do it in Sema.

llvm-svn: 241032
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 7ed9bfc..672fc89 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -2186,9 +2186,6 @@
       assert(Member && "HandleField never returns null");
     }
   } else {
-    assert(InitStyle == ICIS_NoInit ||
-           D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_static);
-
     Member = HandleDeclarator(S, D, TemplateParameterLists);
     if (!Member)
       return nullptr;
@@ -13060,6 +13057,15 @@
   return true;
 }
 
+void Sema::ActOnPureSpecifier(Decl *D, SourceLocation ZeroLoc) {
+  if (D->getFriendObjectKind())
+    Diag(D->getLocation(), diag::err_pure_friend);
+  else if (auto *M = dyn_cast<CXXMethodDecl>(D))
+    CheckPureMethod(M, ZeroLoc);
+  else
+    Diag(D->getLocation(), diag::err_illegal_initializer);
+}
+
 /// \brief Determine whether the given declaration is a static data member.
 static bool isStaticDataMember(const Decl *D) {
   if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(D))