[cfe-dev] Newline vs space in C++ parsing

[Nickolai Zeldovich]

I'm seeing surprising behavior in Clang 3.2 and 3.3-svn (as of a few days 
ago), where newlines seem to be treated differently from spaces in parsing 
C++ code.  In particular, the following code compiles just fine:

  % cat x.cc
  struct s {};

  struct s operator++(struct s a)
  { return a; }
  % clang -c x.cc
  %

but this version, with a newline instead of a space, generates an error:

  % cat x.cc
  struct s {};

  struct s
  operator++(struct s a)
  { return a; }
  % clang -c x.cc
   x.cc:3:9: error: expected ';' after struct
   struct s
           ^
           ;
   x.cc:4:1: error: C++ requires a type specifier for all declarations
   operator++(struct s a)
   ^~~~~~~~
   x.cc:5:10: error: no viable conversion from 'struct s' to 'int'
   { return a; }
            ^
   3 errors generated.
   %

g++ 4.7.2 accepts either variation, and I was expecting newlines and 
spaces to be both treated as whitespace in C++.  Is this a bug in Clang or 
something more subtle?

Nickolai.