bug#16610: 24.3.50; [ruby-mode] Variables named as built-in functions font-locked incorrectly

[Dmitry Gutov <dgutov@yandex.ru>]

On 01.02.2014 17:31, Bozhidar Batsov wrote:
> Variables can’t end with ?, so
> block_given? is always clear. Same goes for exit!. Pretty sure no one
> will ever name a var __xxx__.

Good points.

> `binding` & `caller` seem the most likely
> names in the list to cause a problem like `format`, since they’d be good
> variable names (at least in code making use of metaprogramming).

Still not very likely, though (e.g. compared to `format`, which is in 
every other Rails tutorial). And anyone doing metaprogramming should be 
aware of these two, and would probably name their vars differently.

I have a patch ready, but here's what I'm not sure about: if the 
built-in method that requires arguments is followed by (maybe whitespace 
and) newline, do we highlight it?

If yes, we'll have false positives when a local variable with that name 
is at a line by itself, maybe on the last line of a method, so that its 
value is returned.

If no, any such built-in won't be highlighted until the user types in 
the first argument, which is also suboptimal (if I made a typo, I'll 
have to go back a longer distance).