[BUG] super reuses the variable holding the method id in method_missing

I found this some time ago [ruby-talk:241088] but forgot to report it; it
might be related to Ara's [10851].

The problem seems to have been introduced somewhere between 1.8.4 and 1.8.5:

$ cat super_bug.rb 
def method_missing(m, *a, &b)
  m = :foo
  super
end
sdf 1, 2 do 1 end

$ ruby186 -v super_bug.rb 
ruby 1.8.6 (2007-03-13 patchlevel 0) [i686-linux]
super_bug.rb:3:in `method_missing': undefined method `foo' for main:Object (NoMethodError)
	from super_bug.rb:5
$ ruby185-p12 -v super_bug.rb 
ruby 1.8.5 (2006-12-25 patchlevel 12) [i686-linux]
super_bug.rb:3:in `method_missing': undefined method `foo' for main:Object (NoMethodError)
	from super_bug.rb:5
$ ruby -v super_bug.rb 
ruby 1.8.5 (2006-08-25) [i686-linux]
super_bug.rb:3:in `method_missing': undefined method `foo' for main:Object (NoMethodError)
	from super_bug.rb:5
$ ruby184 -v super_bug.rb 
ruby 1.8.4 (2005-12-24) [i686-linux]
super_bug.rb:3:in `method_missing': undefined method `sdf' for main:Object (NoMethodError)
	from super_bug.rb:5


-- 
Mauricio Fernandez  -   http://eigenclass.org   -  singular Ruby
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