From: Douglas Gregor <dgregor@apple.com>
Date: Thu, 12 Nov 2009 00:03:40 +0000 (+0000)
Subject: Remove an overly-eager assertion when replacing tokens with an
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=eaf75f4e0f65444bb122ade7725a4a32badcbf77;p=clang

Remove an overly-eager assertion when replacing tokens with an
annotation token, because some of the tokens we're annotating might
not be in the set of cached tokens (we could have consumed them
unconditionally).

Also, move the tentative parsing from ParseTemplateTemplateArgument
into the one caller that needs it, improving recovery.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86904 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Lex/PPCaching.cpp b/lib/Lex/PPCaching.cpp
index c3f0eeab58..7c3780ffc0 100644
--- a/lib/Lex/PPCaching.cpp
+++ b/lib/Lex/PPCaching.cpp
@@ -109,6 +109,4 @@ void Preprocessor::AnnotatePreviousCachedTokens(const Token &Tok) {
       return;
     }
   }
-
-  assert(0&&"Didn't find the first token represented by the annotation token!");
 }
diff --git a/lib/Parse/ParseTemplate.cpp b/lib/Parse/ParseTemplate.cpp
index b5063ee44b..16b1c80080 100644
--- a/lib/Parse/ParseTemplate.cpp
+++ b/lib/Parse/ParseTemplate.cpp
@@ -823,15 +823,13 @@ ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
   //   A template-argument for a template template-parameter shall be the name
   //   of a class template or a template alias, expressed as id-expression.
   //   
-  // We perform some tentative parsing at this point, to determine whether
-  // we have an id-expression that refers to a class template or template
-  // alias. The grammar we tentatively parse is:
+  // We parse an id-expression that refers to a class template or template
+  // alias. The grammar we parse is:
   //
   //   nested-name-specifier[opt] template[opt] identifier
   //
   // followed by a token that terminates a template argument, such as ',', 
   // '>', or (in some cases) '>>'.
-  TentativeParsingAction TPA(*this);
   CXXScopeSpec SS; // nested-name-specifier, if present
   ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/0, 
                                  /*EnteringContext=*/false);
@@ -854,10 +852,8 @@ ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
         TemplateTy Template
         = Actions.ActOnDependentTemplateName(TemplateLoc, SS, Name, 
                                              /*ObjectType=*/0);
-        if (Template.get()) {
-          TPA.Commit();
+        if (Template.get())
           return ParsedTemplateArgument(SS, Template, Name.StartLocation);
-        }
       }
     } 
   } else if (Tok.is(tok::identifier)) {
@@ -875,16 +871,12 @@ ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
       if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) {
         // We have an id-expression that refers to a class template or
         // (C++0x) template alias. 
-        TPA.Commit();
         return ParsedTemplateArgument(SS, Template, Name.StartLocation);
       }
     }
   }
   
-  // We don't have a template template argument; revert everything we have
-  // tentatively parsed.
-  TPA.Revert();
-  
+  // We don't have a template template argument.  
   return ParsedTemplateArgument();
 }
 
@@ -912,10 +904,19 @@ ParsedTemplateArgument Parser::ParseTemplateArgument() {
   }
   
   // Try to parse a template template argument.
-  ParsedTemplateArgument TemplateTemplateArgument
-    = ParseTemplateTemplateArgument();
-  if (!TemplateTemplateArgument.isInvalid())
-    return TemplateTemplateArgument;
+  {
+    TentativeParsingAction TPA(*this);
+
+    ParsedTemplateArgument TemplateTemplateArgument
+      = ParseTemplateTemplateArgument();
+    if (!TemplateTemplateArgument.isInvalid()) {
+      TPA.Commit();
+      return TemplateTemplateArgument;
+    }
+    
+    // Revert this tentative parse to parse a non-type template argument.
+    TPA.Revert();
+  }
   
   // Parse a non-type template argument. 
   SourceLocation Loc = Tok.getLocation();
diff --git a/test/SemaTemplate/default-arguments.cpp b/test/SemaTemplate/default-arguments.cpp
index e082693aa5..0247ddc0ef 100644
--- a/test/SemaTemplate/default-arguments.cpp
+++ b/test/SemaTemplate/default-arguments.cpp
@@ -118,3 +118,6 @@ template<typename T,
 X6<int> x6a;
 X6<long> x6b; // expected-note{{while checking a default template argument}}
 X6<long, X5b> x6c;
+
+
+template<template<class> class X = B<int> > struct X7; // expected-error{{must be a class template}}