Parse A::template B as an identifier rather than as a template-id with no

template arguments.

This fixes some cases where we'd incorrectly accept "A::template B" when B is a
kind of template that requires template arguments (in particular, a variable
template or a concept).

llvm-svn: 331013

7 files changed, 63 insertions, 39 deletions

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 3d3abe32ab8..fc0ca613c73 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -5600,12 +5600,11 @@ void Parser::ParseDirectDeclarator(Declarator &D) {
            D.getContext() == DeclaratorContext::MemberContext);
       }
 
-      SourceLocation TemplateKWLoc;
       bool HadScope = D.getCXXScopeSpec().isValid();
       if (ParseUnqualifiedId(D.getCXXScopeSpec(),
                              /*EnteringContext=*/true,
                              /*AllowDestructorName=*/true, AllowConstructorName,
-                             AllowDeductionGuide, nullptr, TemplateKWLoc,
+                             AllowDeductionGuide, nullptr, nullptr,
                              D.getName()) ||
           // Once we're past the identifier, if the scope was bad, mark the
           // whole declarator bad.
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 0c789c9b1c4..ec1177aece2 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -602,7 +602,7 @@ bool Parser::ParseUsingDeclarator(DeclaratorContext Context,
             /*AllowConstructorName=*/!(Tok.is(tok::identifier) &&
                                        NextToken().is(tok::equal)),
             /*AllowDeductionGuide=*/false,
-            nullptr, D.TemplateKWLoc, D.Name))
+            nullptr, nullptr, D.Name))
       return true;
   }
 
@@ -2476,7 +2476,7 @@ Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
       SourceLocation TemplateKWLoc;
       UnqualifiedId Name;
       if (ParseUnqualifiedId(SS, false, true, true, false, nullptr,
-                             TemplateKWLoc, Name)) {
+                             &TemplateKWLoc, Name)) {
         SkipUntil(tok::semi);
         return nullptr;
       }
@@ -2488,6 +2488,7 @@ Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
         return nullptr;
       }
 
+      // FIXME: We should do something with the 'template' keyword here.
       return DeclGroupPtrTy::make(DeclGroupRef(Actions.ActOnUsingDeclaration(
           getCurScope(), AS, /*UsingLoc*/ SourceLocation(),
           /*TypenameLoc*/ SourceLocation(), SS, Name,
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 1b8865edb79..ca5d3bce9cf 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -1755,7 +1755,7 @@ Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
                                     /*AllowConstructorName=*/
                                       getLangOpts().MicrosoftExt, 
                                     /*AllowDeductionGuide=*/false,
-                                    ObjectType, TemplateKWLoc, Name)) {
+                                    ObjectType, &TemplateKWLoc, Name)) {
         (void)Actions.CorrectDelayedTyposInExpr(LHS);
         LHS = ExprError();
       }
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index 7ebd90ef239..8e39adf8a5d 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -553,7 +553,7 @@ ExprResult Parser::tryParseCXXIdExpression(CXXScopeSpec &SS, bool isAddressOfOpe
                          /*AllowDestructorName=*/false,
                          /*AllowConstructorName=*/false,
                          /*AllowDeductionGuide=*/false,
-                         /*ObjectType=*/nullptr, TemplateKWLoc, Name))
+                         /*ObjectType=*/nullptr, &TemplateKWLoc, Name))
     return ExprError();
 
   // This is only the direct operand of an & operator if it is not
@@ -2044,9 +2044,8 @@ bool Parser::ParseUnqualifiedIdTemplateId(CXXScopeSpec &SS,
                                           ParsedType ObjectType,
                                           UnqualifiedId &Id,
                                           bool AssumeTemplateId) {
-  assert((AssumeTemplateId || Tok.is(tok::less)) &&
-         "Expected '<' to finish parsing a template-id");
-  
+  assert(Tok.is(tok::less) && "Expected '<' to finish parsing a template-id");
+
   TemplateTy Template;
   TemplateNameKind TNK = TNK_Non_template;
   switch (Id.getKind()) {
@@ -2142,10 +2141,10 @@ bool Parser::ParseUnqualifiedIdTemplateId(CXXScopeSpec &SS,
   // Parse the enclosed template argument list.
   SourceLocation LAngleLoc, RAngleLoc;
   TemplateArgList TemplateArgs;
-  if (Tok.is(tok::less) && ParseTemplateIdAfterTemplateName(
-                               true, LAngleLoc, TemplateArgs, RAngleLoc))
+  if (ParseTemplateIdAfterTemplateName(true, LAngleLoc, TemplateArgs,
+                                       RAngleLoc))
     return true;
-  
+
   if (Id.getKind() == UnqualifiedIdKind::IK_Identifier ||
       Id.getKind() == UnqualifiedIdKind::IK_OperatorFunctionId ||
       Id.getKind() == UnqualifiedIdKind::IK_LiteralOperatorId) {
@@ -2465,16 +2464,23 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
                                 bool AllowConstructorName,
                                 bool AllowDeductionGuide,
                                 ParsedType ObjectType,
-                                SourceLocation& TemplateKWLoc,
+                                SourceLocation *TemplateKWLoc,
                                 UnqualifiedId &Result) {
+  if (TemplateKWLoc)
+    *TemplateKWLoc = SourceLocation();
 
   // Handle 'A::template B'. This is for template-ids which have not
   // already been annotated by ParseOptionalCXXScopeSpecifier().
   bool TemplateSpecified = false;
-  if (getLangOpts().CPlusPlus && Tok.is(tok::kw_template) &&
-      (ObjectType || SS.isSet())) {
-    TemplateSpecified = true;
-    TemplateKWLoc = ConsumeToken();
+  if (Tok.is(tok::kw_template)) {
+    if (TemplateKWLoc && (ObjectType || SS.isSet())) {
+      TemplateSpecified = true;
+      *TemplateKWLoc = ConsumeToken();
+    } else {
+      SourceLocation TemplateLoc = ConsumeToken();
+      Diag(TemplateLoc, diag::err_unexpected_template_in_unqualified_id)
+        << FixItHint::CreateRemoval(TemplateLoc);
+    }
   }
 
   // unqualified-id:
@@ -2513,11 +2519,18 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
     }
 
     // If the next token is a '<', we may have a template.
-    if (TemplateSpecified || Tok.is(tok::less))
-      return ParseUnqualifiedIdTemplateId(SS, TemplateKWLoc, Id, IdLoc,
-                                          EnteringContext, ObjectType,
-                                          Result, TemplateSpecified);
-    
+    TemplateTy Template;
+    if (Tok.is(tok::less))
+      return ParseUnqualifiedIdTemplateId(
+          SS, TemplateKWLoc ? *TemplateKWLoc : SourceLocation(), Id, IdLoc,
+          EnteringContext, ObjectType, Result, TemplateSpecified);
+    else if (TemplateSpecified &&
+             Actions.ActOnDependentTemplateName(
+                 getCurScope(), SS, *TemplateKWLoc, Result, ObjectType,
+                 EnteringContext, Template,
+                 /*AllowInjectedClassName*/ true) == TNK_Non_template)
+      return true;
+
     return false;
   }
   
@@ -2558,7 +2571,14 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
     // We have already parsed a template-id; consume the annotation token as
     // our unqualified-id.
     Result.setTemplateId(TemplateId);
-    TemplateKWLoc = TemplateId->TemplateKWLoc;
+    SourceLocation TemplateLoc = TemplateId->TemplateKWLoc;
+    if (TemplateLoc.isValid()) {
+      if (TemplateKWLoc && (ObjectType || SS.isSet()))
+        *TemplateKWLoc = TemplateLoc;
+      else
+        Diag(TemplateLoc, diag::err_unexpected_template_in_unqualified_id)
+            << FixItHint::CreateRemoval(TemplateLoc);
+    }
     ConsumeAnnotationToken();
     return false;
   }
@@ -2575,13 +2595,20 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
     // 
     //   template-id:
     //     operator-function-id < template-argument-list[opt] >
+    TemplateTy Template;
     if ((Result.getKind() == UnqualifiedIdKind::IK_OperatorFunctionId ||
          Result.getKind() == UnqualifiedIdKind::IK_LiteralOperatorId) &&
-        (TemplateSpecified || Tok.is(tok::less)))
-      return ParseUnqualifiedIdTemplateId(SS, TemplateKWLoc,
-                                          nullptr, SourceLocation(),
-                                          EnteringContext, ObjectType,
-                                          Result, TemplateSpecified);
+        Tok.is(tok::less))
+      return ParseUnqualifiedIdTemplateId(
+          SS, TemplateKWLoc ? *TemplateKWLoc : SourceLocation(), nullptr,
+          SourceLocation(), EnteringContext, ObjectType, Result,
+          TemplateSpecified);
+    else if (TemplateSpecified &&
+             Actions.ActOnDependentTemplateName(
+                 getCurScope(), SS, *TemplateKWLoc, Result, ObjectType,
+                 EnteringContext, Template,
+                 /*AllowInjectedClassName*/ true) == TNK_Non_template)
+      return true;
 
     return false;
   }
@@ -2649,12 +2676,11 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
     IdentifierInfo *ClassName = Tok.getIdentifierInfo();
     SourceLocation ClassNameLoc = ConsumeToken();
 
-    if (TemplateSpecified || Tok.is(tok::less)) {
+    if (Tok.is(tok::less)) {
       Result.setDestructorName(TildeLoc, nullptr, ClassNameLoc);
-      return ParseUnqualifiedIdTemplateId(SS, TemplateKWLoc,
-                                          ClassName, ClassNameLoc,
-                                          EnteringContext, ObjectType,
-                                          Result, TemplateSpecified);
+      return ParseUnqualifiedIdTemplateId(
+          SS, TemplateKWLoc ? *TemplateKWLoc : SourceLocation(), ClassName,
+          ClassNameLoc, EnteringContext, ObjectType, Result, TemplateSpecified);
     }
 
     // Note that this is a destructor name.
diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index e00bfb845fc..bfd708fe86e 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -1154,7 +1154,6 @@ bool Parser::ParseOpenMPSimpleVarList(
   // Read tokens while ')' or annot_pragma_openmp_end is not found.
   while (Tok.isNot(tok::r_paren) && Tok.isNot(tok::annot_pragma_openmp_end)) {
     CXXScopeSpec SS;
-    SourceLocation TemplateKWLoc;
     UnqualifiedId Name;
     // Read var name.
     Token PrevTok = Tok;
@@ -1166,7 +1165,7 @@ bool Parser::ParseOpenMPSimpleVarList(
       SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                 StopBeforeMatch);
     } else if (ParseUnqualifiedId(SS, false, false, false, false, nullptr,
-                                  TemplateKWLoc, Name)) {
+                                  nullptr, Name)) {
       IsCorrect = false;
       SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
                 StopBeforeMatch);
@@ -1648,7 +1647,6 @@ OMPClause *Parser::ParseOpenMPSingleExprWithArgClause(OpenMPClauseKind Kind,
 
 static bool ParseReductionId(Parser &P, CXXScopeSpec &ReductionIdScopeSpec,
                              UnqualifiedId &ReductionId) {
-  SourceLocation TemplateKWLoc;
   if (ReductionIdScopeSpec.isEmpty()) {
     auto OOK = OO_None;
     switch (P.getCurToken().getKind()) {
@@ -1690,7 +1688,7 @@ static bool ParseReductionId(Parser &P, CXXScopeSpec &ReductionIdScopeSpec,
                               /*AllowDestructorName*/ false,
                               /*AllowConstructorName*/ false,
                               /*AllowDeductionGuide*/ false,
-                              nullptr, TemplateKWLoc, ReductionId);
+                              nullptr, nullptr, ReductionId);
 }
 
 /// Parses clauses with list.
diff --git a/clang/lib/Parse/ParseStmtAsm.cpp b/clang/lib/Parse/ParseStmtAsm.cpp
index d81029e2797..290723c2953 100644
--- a/clang/lib/Parse/ParseStmtAsm.cpp
+++ b/clang/lib/Parse/ParseStmtAsm.cpp
@@ -239,7 +239,7 @@ ExprResult Parser::ParseMSAsmIdentifier(llvm::SmallVectorImpl<Token> &LineToks,
                                  /*AllowDestructorName=*/false,
                                  /*AllowConstructorName=*/false,
                                  /*AllowDeductionGuide=*/false,
-                                 /*ObjectType=*/nullptr, TemplateKWLoc, Id);
+                                 /*ObjectType=*/nullptr, &TemplateKWLoc, Id);
     // Perform the lookup.
     Result = Actions.LookupInlineAsmIdentifier(SS, TemplateKWLoc, Id,
                                                IsUnevaluatedContext);
diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index d8f9f7a3902..036688cf8f9 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -2002,7 +2002,7 @@ bool Parser::ParseMicrosoftIfExistsCondition(IfExistsCondition& Result) {
   if (ParseUnqualifiedId(
           Result.SS, /*EnteringContext*/false, /*AllowDestructorName*/true,
           /*AllowConstructorName*/true, /*AllowDeductionGuide*/false, nullptr,
-          TemplateKWLoc, Result.Name)) {
+          &TemplateKWLoc, Result.Name)) {
     T.skipToEnd();
     return true;
   }