1 files changed, 16 insertions, 15 deletions

diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index cd2e3971884..6200363b3bc 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -1239,7 +1239,8 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
   // Parse the (optional) nested-name-specifier.
   CXXScopeSpec &SS = DS.getTypeSpecScope();
   if (getLangOpts().CPlusPlus) {
-    // "FOO : BAR" is not a potential typo for "FOO::BAR".
+    // "FOO : BAR" is not a potential typo for "FOO::BAR".  In this context it
+    // is a base-specifier-list.
     ColonProtectionRAIIObject X(*this);
 
     if (ParseOptionalCXXScopeSpecifier(SS, ParsedType(), EnteringContext))
@@ -1926,14 +1927,8 @@ void Parser::ParseCXXMemberDeclaratorBeforeInitializer(
   //   declarator pure-specifier[opt]
   //   declarator brace-or-equal-initializer[opt]
   //   identifier[opt] ':' constant-expression
-  if (Tok.isNot(tok::colon)) {
-    // Don't parse FOO:BAR as if it were a typo for FOO::BAR, in this context it
-    // is a bitfield.
-    // FIXME: This should only apply when parsing the id-expression (see
-    // PR18587).
-    ColonProtectionRAIIObject X(*this);
+  if (Tok.isNot(tok::colon))
     ParseDeclarator(DeclaratorInfo);
-  }
 
   if (!DeclaratorInfo.isFunctionDeclarator() && TryConsumeToken(tok::colon)) {
     BitfieldSize = ParseConstantExpression();
@@ -2015,6 +2010,14 @@ void Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
     return;
   }
 
+  // Turn on colon protection early, while parsing declspec, although there is
+  // nothing to protect there. It prevents from false errors if error recovery
+  // incorrectly determines where the declspec ends, as in the example:
+  //   struct A { enum class B { C }; };
+  //   const int C = 4;
+  //   struct D { A::B : C; };
+  ColonProtectionRAIIObject X(*this);
+
   // Access declarations.
   bool MalformedTypeSpec = false;
   if (!TemplateInfo.Kind &&
@@ -2128,13 +2131,11 @@ void Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
   if (MalformedTypeSpec)
     DS.SetTypeSpecError();
 
-  {
-    // Don't parse FOO:BAR as if it were a typo for FOO::BAR, in this context it
-    // is a bitfield.
-    ColonProtectionRAIIObject X(*this);
-    ParseDeclarationSpecifiers(DS, TemplateInfo, AS, DSC_class,
-                               &CommonLateParsedAttrs);
-  }
+  ParseDeclarationSpecifiers(DS, TemplateInfo, AS, DSC_class,
+                             &CommonLateParsedAttrs);
+
+  // Turn off colon protection that was set for declspec.
+  X.restore();
 
   // If we had a free-standing type definition with a missing semicolon, we
   // may get this far before the problem becomes obvious.