The coding standards doc states to format lambdas like blocks as long as they're the last arg:

  http://www.llvm.org/docs/CodingStandards.html#format-lambdas-like-blocks-of-code

However, clang-format only seems to do that if the opening brace of the lambda is on the same line as the start of the function call:

  some_call_to_a_function_with_a_long_name(arg1, arg2, [](int x) {
    int y = x * x;
    return y;
  });

vs

  some_call_to_a_function_with_a_long_name(long_arg1, really_long_arg2,
                                           [](int x) {
                                             int y = x * x;
                                             return y;
                                           });

The latter should really be:

  some_call_to_a_function_with_a_long_name(long_arg1, really_long_arg2,
                                           [](int x) {
    int y = x * x;
    return y;
  });