Revert "[c++1z] P0195R2: Support pack-expansion of using-declarations."

This reverts commit r290080 as it leads to many Clang crashes, e.g.:
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-quick/builds/1814

llvm-svn: 290092

1 files changed, 63 insertions, 16 deletions

diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 4002b09d2bc..d31d1142374 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -560,9 +560,7 @@ bool Parser::ParseUsingDeclarator(unsigned Context, UsingDeclarator &D) {
   //   nested-name-specifier, the name is [...] considered to name the
   //   constructor.
   if (getLangOpts().CPlusPlus11 && Context == Declarator::MemberContext &&
-      Tok.is(tok::identifier) &&
-      (NextToken().is(tok::semi) || NextToken().is(tok::comma) ||
-       NextToken().is(tok::ellipsis)) &&
+      Tok.is(tok::identifier) && NextToken().is(tok::semi) &&
       D.SS.isNotEmpty() && LastII == Tok.getIdentifierInfo() &&
       !D.SS.getScopeRep()->getAsNamespace() &&
       !D.SS.getScopeRep()->getAsNamespaceAlias()) {
@@ -580,10 +578,7 @@ bool Parser::ParseUsingDeclarator(unsigned Context, UsingDeclarator &D) {
       return true;
   }
 
-  if (TryConsumeToken(tok::ellipsis, D.EllipsisLoc))
-    Diag(Tok.getLocation(), getLangOpts().CPlusPlus1z ?
-         diag::warn_cxx1z_compat_using_declaration_pack :
-         diag::ext_using_declaration_pack);
+  // FIXME: Parse optional ellipsis
 
   return false;
 }
@@ -683,9 +678,9 @@ Parser::ParseUsingDeclaration(unsigned Context,
         D.TypenameLoc = SourceLocation();
       }
 
-      Decl *UD = Actions.ActOnUsingDeclaration(getCurScope(), AS, UsingLoc,
-                                               D.TypenameLoc, D.SS, D.Name,
-                                               D.EllipsisLoc, Attrs.getList());
+      Decl *UD =
+          Actions.ActOnUsingDeclaration(getCurScope(), AS, UsingLoc, D.SS,
+                                        D.Name, Attrs.getList(), D.TypenameLoc);
       if (UD)
         DeclsInGroup.push_back(UD);
     }
@@ -713,6 +708,62 @@ Parser::ParseUsingDeclaration(unsigned Context,
   return Actions.BuildDeclaratorGroup(DeclsInGroup, /*MayContainAuto*/false);
 }
 
+Decl *Parser::ParseAliasTemplate(const ParsedTemplateInfo &TemplateInfo,
+                                 SourceLocation &DeclEnd, AccessSpecifier AS,
+                                 ParsedAttributesWithRange &MisplacedAttrs1) {
+  assert(Tok.is(tok::kw_using) && "Not using token");
+  ObjCDeclContextSwitch ObjCDC(*this);
+  
+  // Eat 'using'.
+  SourceLocation UsingLoc = ConsumeToken();
+  if (Tok.is(tok::code_completion)) {
+    Actions.CodeCompleteUsing(getCurScope());
+    cutOffParsing();
+    return nullptr;
+  }
+
+  // 'using namespace' means this is a using-directive.
+  if (Tok.is(tok::kw_namespace)) {
+    SourceRange R = TemplateInfo.getSourceRange();
+    Diag(UsingLoc, diag::err_templated_using_directive_declaration)
+        << 0 /* directive */ << R;
+    SkipUntil(tok::semi);
+    return nullptr;
+  }
+
+  // Check for misplaced attributes before the identifier.
+  ParsedAttributesWithRange MisplacedAttrs2(AttrFactory);
+  MaybeParseCXX11Attributes(MisplacedAttrs2);
+
+  // FIXME: Just parse an identifier here?
+  UsingDeclarator D;
+  if (ParseUsingDeclarator(Declarator::FileContext, D)) {
+    SkipUntil(tok::semi);
+    return nullptr;
+  }
+
+  ParsedAttributesWithRange Attrs(AttrFactory);
+
+  // If we had any misplaced attributes from earlier, this is where they
+  // should have been written.
+  for (auto *MisplacedAttrs : {&MisplacedAttrs1, &MisplacedAttrs2}) {
+    if (MisplacedAttrs->Range.isValid()) {
+      Diag(MisplacedAttrs->Range.getBegin(), diag::err_attributes_not_allowed)
+        << FixItHint::CreateInsertionFromRange(
+               Tok.getLocation(),
+               CharSourceRange::getTokenRange(MisplacedAttrs->Range))
+        << FixItHint::CreateRemoval(MisplacedAttrs->Range);
+      Attrs.takeAllFrom(*MisplacedAttrs);
+    }
+  }
+
+  MaybeParseGNUAttributes(Attrs);
+  MaybeParseCXX11Attributes(Attrs);
+
+  return ParseAliasDeclarationAfterDeclarator(TemplateInfo, UsingLoc, D,
+                                              DeclEnd, AS, Attrs);
+}
+
 Decl *Parser::ParseAliasDeclarationAfterDeclarator(
     const ParsedTemplateInfo &TemplateInfo, SourceLocation UsingLoc,
     UsingDeclarator &D, SourceLocation &DeclEnd, AccessSpecifier AS,
@@ -762,9 +813,6 @@ Decl *Parser::ParseAliasDeclarationAfterDeclarator(
   else if (D.SS.isNotEmpty())
     Diag(D.SS.getBeginLoc(), diag::err_alias_declaration_not_identifier)
       << FixItHint::CreateRemoval(D.SS.getRange());
-  if (D.EllipsisLoc.isValid())
-    Diag(D.EllipsisLoc, diag::err_alias_declaration_pack_expansion)
-      << FixItHint::CreateRemoval(SourceRange(D.EllipsisLoc));
 
   Decl *DeclFromDeclSpec = nullptr;
   TypeResult TypeAlias =
@@ -2439,9 +2487,8 @@ Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
       }
 
       return DeclGroupPtrTy::make(DeclGroupRef(Actions.ActOnUsingDeclaration(
-          getCurScope(), AS, /*UsingLoc*/ SourceLocation(),
-          /*TypenameLoc*/ SourceLocation(), SS, Name,
-          /*EllipsisLoc*/ SourceLocation(), /*AttrList*/ nullptr)));
+          getCurScope(), AS, /*UsingLoc*/SourceLocation(), SS, Name,
+          /*AttrList*/nullptr, /*TypenameLoc*/SourceLocation())));
     }
   }