[FOLD] don't annotate types as id-expressions

Author: sdkrystian

clang/include/clang/Parse/Parser.h

@@ -1907,6 +1907,7 @@ class Parser : public CodeCompletionHandler {
   }
 
   bool diagnoseUnknownTemplateId(ExprResult TemplateName, SourceLocation Less);
+  bool isMissingTemplateKeywordBeforeScope();
   void checkPotentialAngleBracket(ExprResult &PotentialTemplateName);
   bool checkPotentialAngleBracketDelimiter(const AngleBracketTracker::Loc &,
                                            const Token &OpToken);

clang/lib/Parse/ParseTemplate.cpp

@@ -1779,6 +1779,36 @@ void Parser::checkPotentialAngleBracket(ExprResult &PotentialTemplateName) {
                     Priority);
 }
 
+bool Parser::isMissingTemplateKeywordBeforeScope() {
+  assert(Tok.is(tok::coloncolon));
+  Sema::DisableTypoCorrectionRAII DTC(Actions);
+  ColonProtectionRAIIObject ColonProtection(*this);
+
+  SourceLocation StartLoc = Tok.getLocation();
+  if (TryAnnotateTypeOrScopeToken())
+    return true;
+  if (Tok.isSimpleTypeSpecifier(getLangOpts()))
+    return false;
+  CXXScopeSpec SS;
+  ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
+                                 /*ObjectHasErrors=*/false,
+                                 /*EnteringContext=*/false);
+  ExprResult Result = tryParseCXXIdExpression(SS, /*isAddressOfOperand=*/false);
+
+  if (PP.isBacktrackEnabled())
+    PP.RevertCachedTokens(1);
+  else
+    PP.EnterToken(Tok, /*IsReinject=*/true);
+
+  SourceLocation EndLoc = Tok.getLocation();
+  Tok.setLocation(StartLoc);
+  Tok.setKind(tok::annot_primary_expr);
+  setExprAnnotation(Tok, Result);
+  Tok.setAnnotationEndLoc(EndLoc);
+  PP.AnnotateCachedTokens(Tok);
+  return Result.isInvalid();
+}
+
 bool Parser::checkPotentialAngleBracketDelimiter(
     const AngleBracketTracker::Loc &LAngle, const Token &OpToken) {
   // If a comma in an expression context is followed by a type that can be a
@@ -1802,36 +1832,14 @@ bool Parser::checkPotentialAngleBracketDelimiter(
     return true;
   }
 
-  if (OpToken.is(tok::greater) && Tok.is(tok::coloncolon)) {
-    Sema::DisableTypoCorrectionRAII DTC(Actions);
-
-    SourceLocation StartLoc = Tok.getLocation();
-    CXXScopeSpec SS;
-    ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
-                                   /*ObjectHasErrors=*/false,
-                                   /*EnteringContext=*/false);
-    ExprResult Result =
-        tryParseCXXIdExpression(SS, /*isAddressOfOperand=*/false);
-
-    if (PP.isBacktrackEnabled())
-      PP.RevertCachedTokens(1);
-    else
-      PP.EnterToken(Tok, /*IsReinject=*/true);
-
-    SourceLocation EndLoc = Tok.getLocation();
-    Tok.setLocation(StartLoc);
-    Tok.setKind(tok::annot_primary_expr);
-    setExprAnnotation(Tok, Result);
-    Tok.setAnnotationEndLoc(EndLoc);
-    PP.AnnotateCachedTokens(Tok);
-
-    if (Result.isInvalid()) {
-      Actions.diagnoseExprIntendedAsTemplateName(
-          getCurScope(), LAngle.TemplateName, LAngle.LessLoc,
-          OpToken.getLocation());
-      AngleBrackets.clear(*this);
-      return true;
-    }
+  if (OpToken.is(tok::greater) && Tok.is(tok::coloncolon) &&
+      !NextToken().isOneOf(tok::kw_new, tok::kw_delete) &&
+      isMissingTemplateKeywordBeforeScope()) {
+    Actions.diagnoseExprIntendedAsTemplateName(
+        getCurScope(), LAngle.TemplateName, LAngle.LessLoc,
+        OpToken.getLocation());
+    AngleBrackets.clear(*this);
+    return true;
   }
 
   // After a '>' (etc), we're no longer potentially in a construct that's

clang/lib/Sema/SemaCXXScopeSpec.cpp

@@ -685,13 +685,15 @@ bool Sema::BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
   if (ErrorRecoveryLookup)
     return true;
 
+#if 0
   // If we didn't find anything during our lookup, try again with
   // ordinary name lookup, which can help us produce better error
   // messages.
   if (Found.empty()) {
     Found.clear(LookupOrdinaryName);
     LookupName(Found, S);
   }
+#endif
 
   // In Microsoft mode, if we are within a templated function and we can't
   // resolve Identifier, then extend the SS with Identifier. This will have
@@ -733,6 +735,7 @@ bool Sema::BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
     }
   }
 
+#if 1
   if (!Found.empty()) {
     if (TypeDecl *TD = Found.getAsSingle<TypeDecl>()) {
       Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
@@ -754,6 +757,7 @@ bool Sema::BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
   else
     Diag(IdInfo.IdentifierLoc, diag::err_undeclared_var_use)
         << IdInfo.Identifier;
+#endif
 
   return true;
 }

clang/test/SemaCXX/nested-name-spec.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -std=c++98 -verify -fblocks %s 
+// RUN: %clang_cc1 -fsyntax-only -std=c++98 -verify -fblocks %s
 namespace A {
   struct C {
     static int cx;
@@ -109,7 +109,7 @@ void A2::CC::NC::m(); // expected-error{{out-of-line declaration of a member mus
 
 namespace E {
   int X = 5;
-  
+
   namespace Nested {
     enum E {
       X = 0
@@ -143,7 +143,7 @@ Operators::operator bool() {
 
 namespace A {
   void g(int&); // expected-note{{type of 1st parameter of member declaration does not match definition ('int &' vs 'const int &')}}
-} 
+}
 
 void A::f() {} // expected-error-re{{out-of-line definition of 'f' does not match any declaration in namespace 'A'{{$}}}}
 
@@ -458,7 +458,7 @@ namespace A {
 class B {
   typedef C D; // expected-error{{unknown type name 'C'}}
   A::D::F;
-  // expected-error@-1{{'PR30619::A::B::D' (aka 'int') is not a class, namespace, or enumeration}}
+  // expected-error@-1{{no member named 'D' in namespace 'PR30619::A'}}
 };
 }
 }