Extend the error recovery for a template-argument-list terminated by '>>' to

also deal with '>>>' (in CUDA), '>=', and '>>='. Fix the FixItHints logic to
deal with cases where the token is followed by an adjacent '=', '==', '>=',
'>>=', or '>>>' token, where a naive fix-it would result in a differing token
stream on a re-lex.

llvm-svn: 158652

clang/include/clang/Basic/DiagnosticParseKinds.td

@@ -498,6 +498,9 @@ def err_id_after_template_in_nested_name_spec : Error<
   "expected template name after 'template' keyword in nested name specifier">;
 def err_two_right_angle_brackets_need_space : Error<
   "a space is required between consecutive right angle brackets (use '> >')">;
+def err_right_angle_bracket_equal_needs_space : Error<
+  "a space is required between a right angle bracket and an equals sign "
+  "(use '> =')">;
 def warn_cxx0x_right_shift_in_template_arg : Warning<
   "use of right-shift operator ('>>') in template argument will require "
   "parentheses in C++11">, InGroup<CXX11Compat>;

clang/include/clang/Parse/Parser.h

@@ -1215,6 +1215,8 @@ private:
   // C++ Expressions
   ExprResult ParseCXXIdExpression(bool isAddressOfOperand = false);
 
+  bool areTokensAdjacent(const Token &A, const Token &B);
+
   void CheckForTemplateAndDigraph(Token &Next, ParsedType ObjectTypePtr,
                                   bool EnteringContext, IdentifierInfo &II,
                                   CXXScopeSpec &SS);

clang/lib/Parse/ParseExprCXX.cpp

@@ -36,7 +36,7 @@ static int SelectDigraphErrorMessage(tok::TokenKind Kind) {
 }
 
 // Are the two tokens adjacent in the same source file?
-static bool AreTokensAdjacent(Preprocessor &PP, Token &First, Token &Second) {
+bool Parser::areTokensAdjacent(const Token &First, const Token &Second) {
   SourceManager &SM = PP.getSourceManager();
   SourceLocation FirstLoc = SM.getSpellingLoc(First.getLocation());
   SourceLocation FirstEnd = FirstLoc.getLocWithOffset(First.getLength());
@@ -80,7 +80,7 @@ void Parser::CheckForTemplateAndDigraph(Token &Next, ParsedType ObjectType,
     return;
 
   Token SecondToken = GetLookAheadToken(2);
-  if (!SecondToken.is(tok::colon) || !AreTokensAdjacent(PP, Next, SecondToken))
+  if (!SecondToken.is(tok::colon) || !areTokensAdjacent(Next, SecondToken))
     return;
 
   TemplateTy Template;
@@ -921,7 +921,7 @@ ExprResult Parser::ParseCXXCasts() {
   // diagnose error, suggest fix, and recover parsing.
   Token Next = NextToken();
   if (Tok.is(tok::l_square) && Tok.getLength() == 2 && Next.is(tok::colon) &&
-      AreTokensAdjacent(PP, Tok, Next))
+      areTokensAdjacent(Tok, Next))
     FixDigraph(*this, PP, Tok, Next, Kind, /*AtDigraph*/true);
 
   if (ExpectAndConsume(tok::less, diag::err_expected_less_after, CastName))

clang/lib/Parse/ParseTemplate.cpp

@@ -316,6 +316,11 @@ bool Parser::ParseTemplateParameters(unsigned Depth,
     Failed = ParseTemplateParameterList(Depth, TemplateParams);
 
   if (Tok.is(tok::greatergreater)) {
+    // No diagnostic required here: a template-parameter-list can only be
+    // followed by a declaration or, for a template template parameter, the
+    // 'class' keyword. Therefore, the second '>' will be diagnosed later.
+    // This matters for elegant diagnosis of:
+    //   template<template<typename>> struct S;
     Tok.setKind(tok::greater);
     RAngleLoc = Tok.getLocation();
     Tok.setLocation(Tok.getLocation().getLocWithOffset(1));
@@ -713,34 +718,104 @@ Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template,
     }
   }
 
-  if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) {
+  // What will be left once we've consumed the '>'.
+  tok::TokenKind RemainingToken;
+  const char *ReplacementStr = "> >";
+
+  switch (Tok.getKind()) {
+  default:
     Diag(Tok.getLocation(), diag::err_expected_greater);
     return true;
+
+  case tok::greater:
+    // Determine the location of the '>' token. Only consume this token
+    // if the caller asked us to.
+    RAngleLoc = Tok.getLocation();
+    if (ConsumeLastToken)
+      ConsumeToken();
+    return false;
+
+  case tok::greatergreater:
+    RemainingToken = tok::greater;
+    break;
+
+  case tok::greatergreatergreater:
+    RemainingToken = tok::greatergreater;
+    break;
+
+  case tok::greaterequal:
+    RemainingToken = tok::equal;
+    ReplacementStr = "> =";
+    break;
+
+  case tok::greatergreaterequal:
+    RemainingToken = tok::greaterequal;
+    break;
   }
 
-  // Determine the location of the '>' or '>>'. Only consume this
-  // token if the caller asked us to.
+  // This template-id is terminated by a token which starts with a '>'. Outside
+  // C++11, this is now error recovery, and in C++11, this is error recovery if
+  // the token isn't '>>'.
+
   RAngleLoc = Tok.getLocation();
 
-  if (Tok.is(tok::greatergreater)) {
-    const char *ReplaceStr = "> >";
-    if (NextToken().is(tok::greater) || NextToken().is(tok::greatergreater))
-      ReplaceStr = "> > ";
+  // The source range of the '>>' or '>=' at the start of the token.
+  CharSourceRange ReplacementRange =
+      CharSourceRange::getCharRange(RAngleLoc,
+          Lexer::AdvanceToTokenCharacter(RAngleLoc, 2, PP.getSourceManager(),
+                                         getLangOpts()));
 
-    Diag(Tok.getLocation(), getLangOpts().CPlusPlus0x ?
-         diag::warn_cxx98_compat_two_right_angle_brackets :
-         diag::err_two_right_angle_brackets_need_space)
-      << FixItHint::CreateReplacement(SourceRange(Tok.getLocation()),
-                                      ReplaceStr);
+  // A hint to put a space between the '>>'s. In order to make the hint as
+  // clear as possible, we include the characters either side of the space in
+  // the replacement, rather than just inserting a space at SecondCharLoc.
+  FixItHint Hint1 = FixItHint::CreateReplacement(ReplacementRange,
+                                                 ReplacementStr);
 
-    Tok.setKind(tok::greater);
-    if (!ConsumeLastToken) {
-      // Since we're not supposed to consume the '>>' token, we need
-      // to insert a second '>' token after the first.
-      PP.EnterToken(Tok);
-    }
-  } else if (ConsumeLastToken)
+  // A hint to put another space after the token, if it would otherwise be
+  // lexed differently.
+  FixItHint Hint2;
+  Token Next = NextToken();
+  if ((RemainingToken == tok::greater ||
+       RemainingToken == tok::greatergreater) &&
+      (Next.is(tok::greater) || Next.is(tok::greatergreater) ||
+       Next.is(tok::greatergreatergreater) || Next.is(tok::equal) ||
+       Next.is(tok::greaterequal) || Next.is(tok::greatergreaterequal) ||
+       Next.is(tok::equalequal)) &&
+      areTokensAdjacent(Tok, Next))
+    Hint2 = FixItHint::CreateInsertion(Next.getLocation(), " ");
+
+  unsigned DiagId = diag::err_two_right_angle_brackets_need_space;
+  if (getLangOpts().CPlusPlus0x && Tok.is(tok::greatergreater))
+    DiagId = diag::warn_cxx98_compat_two_right_angle_brackets;
+  else if (Tok.is(tok::greaterequal))
+    DiagId = diag::err_right_angle_bracket_equal_needs_space;
+  Diag(Tok.getLocation(), DiagId) << Hint1 << Hint2;
+
+  // Strip the initial '>' from the token.
+  if (RemainingToken == tok::equal && Next.is(tok::equal) &&
+      areTokensAdjacent(Tok, Next)) {
+    // Join two adjacent '=' tokens into one, for cases like:
+    //   void (*p)() = f<int>;
+    //   return f<int>==p;
     ConsumeToken();
+    Tok.setKind(tok::equalequal);
+    Tok.setLength(Tok.getLength() + 1);
+  } else {
+    Tok.setKind(RemainingToken);
+    Tok.setLength(Tok.getLength() - 1);
+  }
+  Tok.setLocation(Lexer::AdvanceToTokenCharacter(RAngleLoc, 1,
+                                                 PP.getSourceManager(),
+                                                 getLangOpts()));
+
+  if (!ConsumeLastToken) {
+    // Since we're not supposed to consume the '>' token, we need to push
+    // this token and revert the current token back to the '>'.
+    PP.EnterToken(Tok);
+    Tok.setKind(tok::greater);
+    Tok.setLength(1);
+    Tok.setLocation(RAngleLoc);
+  }
 
   return false;
 }

clang/test/FixIt/fixit.cpp

@@ -260,3 +260,34 @@ bool Foo::isGood() { // expected-error {{out-of-line definition of 'isGood' does
 }
 void Foo::beEvil() {} // expected-error {{out-of-line definition of 'beEvil' does not match any declaration in namespace 'redecl_typo::Foo'; did you mean 'BeEvil'?}}
 }
+
+// Test behavior when a template-id is ended by a token which starts with '>'.
+namespace greatergreater {
+  template<typename T> struct S { S(); S(T); };
+  void f(S<int>=0); // expected-error {{a space is required between a right angle bracket and an equals sign (use '> =')}}
+
+  // FIXME: The fix-its here overlap so -fixit mode can't apply the second one.
+  //void f(S<S<int>>=S<int>());
+
+  struct Shr {
+    template<typename T> Shr(T);
+    template<typename T> void operator >>=(T);
+  };
+
+  template<template<typename>> struct TemplateTemplateParam; // expected-error {{requires 'class'}}
+
+  template<typename T> void t();
+  void g() {
+    void (*p)() = &t<int>;
+    (void)(&t<int>==p); // expected-error {{use '> ='}}
+    (void)(&t<int>>=p); // expected-error {{use '> >'}}
+    (void)(&t<S<int>>>=p); // expected-error {{use '> >'}}
+    (Shr)&t<S<int>>>>=p; // expected-error {{use '> >'}}
+
+    // FIXME: We correct this to '&t<int> > >= p;' not '&t<int> >>= p;'
+    //(Shr)&t<int>>>=p;
+
+    // FIXME: The fix-its here overlap.
+    //(void)(&t<S<int>>==p);
+  }
+}

clang/test/Parser/cuda-kernel-call.cu

@@ -1,9 +1,16 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
 
+template<typename> struct S {};
+template<typename> void f();
+
 void foo(void) {
   foo<<<1;      // expected-error {{expected '>>>'}} expected-note {{to match this '<<<'}}
 
   foo<<<1,1>>>; // expected-error {{expected '('}}
 
   foo<<<>>>();  // expected-error {{expected expression}}
+
+  S<S<S<int>>> s; // expected-error 2{{use '> >'}}
+
+  (void)(&f<S<S<int>>>==0); // expected-error 2{{use '> >'}}
 }

clang/test/Parser/cxx-template-argument.cpp

@@ -10,3 +10,18 @@ A<int x; // expected-error {{expected '>'}}
 // PR8912
 template <bool> struct S {};
 S<bool(2 > 1)> s;
+
+// Test behavior when a template-id is ended by a token which starts with '>'.
+namespace greatergreater {
+  template<typename T> struct S { S(); S(T); };
+  void f(S<int>=0); // expected-error {{a space is required between a right angle bracket and an equals sign (use '> =')}}
+  void f(S<S<int>>=S<int>()); // expected-error {{use '> >'}} expected-error {{use '> ='}}
+  template<typename T> void t();
+  void g() {
+    void (*p)() = &t<int>;
+    (void)(&t<int>==p); // expected-error {{use '> ='}}
+    (void)(&t<int>>=p); // expected-error {{use '> >'}}
+    (void)(&t<S<int>>>=p); // expected-error {{use '> >'}}
+    (void)(&t<S<int>>==p); // expected-error {{use '> >'}} expected-error {{use '> ='}}
+  }
+}