[cfe-commits] r153887 - in /cfe/trunk: include/clang/Basic/DiagnosticParseKinds.td lib/Parse/ParseTemplate.cpp test/FixIt/fixit.cpp test/Parser/cxx-template-decl.cpp

[David Blaikie]

Author: dblaikie
Date: Mon Apr  2 14:15:28 2012
New Revision: 153887

URL: http://llvm.org/viewvc/llvm-project?rev=153887&view=rev
Log:
Correct error recovery when missing 'class' in a template template parameter.

The diagnostic message correctly informs the user that they have omitted the
'class' keyword, but neither suggests this insertion as a fixit, nor attempts
to recover as if they had provided the keyword.

This fixes the recovery, adds the fixit, and adds a separate diagnostic and
corresponding replacement fixit for cases where the user wrote 'struct' or
'typename' instead of 'class' (suggested by Richard Smith as a possible common
mistake).

I'm not sure the diagnostic message for either the original or new cases feel
very Clang-esque, so I'm open to suggestions there. The fixit hints make it
fairly easy to see what's required, though.

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
    cfe/trunk/lib/Parse/ParseTemplate.cpp
    cfe/trunk/test/FixIt/fixit.cpp
    cfe/trunk/test/Parser/cxx-template-decl.cpp

Modified: cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td?rev=153887&r1=153886&r2=153887&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td Mon Apr  2 14:15:28 2012
@@ -480,6 +480,7 @@
 def err_expected_comma_greater : Error<
   "expected ',' or '>' in template-parameter-list">;
 def err_expected_class_before : Error<"expected 'class' before '%0'">;
+def err_expected_class_instead : Error<"expected 'class' instead of '%0'">;
 def err_template_spec_syntax_non_template : Error<
   "identifier followed by '<' indicates a class template specialization but "
   "%0 %select{does not refer to a template|refers to a function "

Modified: cfe/trunk/lib/Parse/ParseTemplate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseTemplate.cpp?rev=153887&r1=153886&r2=153887&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseTemplate.cpp (original)
+++ cfe/trunk/lib/Parse/ParseTemplate.cpp Mon Apr  2 14:15:28 2012
@@ -540,12 +540,17 @@
 
   // Generate a meaningful error if the user forgot to put class before the
   // identifier, comma, or greater.
-  if (!Tok.is(tok::kw_class)) {
-    Diag(Tok.getLocation(), diag::err_expected_class_before)
-      << PP.getSpelling(Tok);
-    return 0;
-  }
-  ConsumeToken();
+  if (Tok.is(tok::kw_typename) || Tok.is(tok::kw_struct)) {
+    Diag(Tok.getLocation(), diag::err_expected_class_instead)
+      << PP.getSpelling(Tok)
+      << FixItHint::CreateReplacement(Tok.getLocation(), "class");
+    ConsumeToken();
+  } else if (!Tok.is(tok::kw_class))
+      Diag(Tok.getLocation(), diag::err_expected_class_before)
+        << PP.getSpelling(Tok)
+        << FixItHint::CreateInsertion(Tok.getLocation(), "class ");
+  else 
+    ConsumeToken();
 
   // Parse the ellipsis, if given.
   SourceLocation EllipsisLoc;

Modified: cfe/trunk/test/FixIt/fixit.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/FixIt/fixit.cpp?rev=153887&r1=153886&r2=153887&view=diff
==============================================================================
--- cfe/trunk/test/FixIt/fixit.cpp (original)
+++ cfe/trunk/test/FixIt/fixit.cpp Mon Apr  2 14:15:28 2012
@@ -199,3 +199,8 @@
   expected-error {{missing 'typename' prior to dependent}}
   return Mystery<T>::get();
 }
+
+template<template<typename> Foo, // expected-error {{expected 'class' before 'Foo'}}
+         template<typename> typename Bar, // expected-error {{expected 'class' instead of 'typename'}}
+         template<typename> struct Baz> // expected-error {{expected 'class' instead of 'struct'}}
+void func();

Modified: cfe/trunk/test/Parser/cxx-template-decl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/cxx-template-decl.cpp?rev=153887&r1=153886&r2=153887&view=diff
==============================================================================
--- cfe/trunk/test/Parser/cxx-template-decl.cpp (original)
+++ cfe/trunk/test/Parser/cxx-template-decl.cpp Mon Apr  2 14:15:28 2012
@@ -11,10 +11,8 @@
 // expected-warning {{declaration does not declare anything}}
 template <template X> struct Err1; // expected-error {{expected '<' after 'template'}} \
 // expected-error{{extraneous}}
-template <template <typename> > struct Err2;       // expected-error {{expected 'class' before '>'}} \
-// expected-error{{extraneous}}
-template <template <typename> Foo> struct Err3;    // expected-error {{expected 'class' before 'Foo'}} \
-// expected-error{{extraneous}}
+template <template <typename> > struct Err2;       // expected-error {{expected 'class' before '>'}}
+template <template <typename> Foo> struct Err3;    // expected-error {{expected 'class' before 'Foo'}}
 
 // Template function declarations
 template <typename T> void foo();