An over enthusiastic warning ?

[Matthias Lang]

Roger Price writes:
 > The following code was produced by a compiler [1] which replaced unused 
 > variables U4 and U5 by wildcards,

Calling _U4 a 'wildcard' seems a bit misleading, because it leads to
the thought that _U4 is a wildcard in the same way as _ is a wildcard,
which is not the case. For example:

  f(_U, _U) -> same;
  f(_U, _V) -> different.

  5> roger:f(a,b).
  different
  6> roger:f(a,a).
  same

Matthias (aware that I've avoided most of your implied question and
quite probably told you something you already know)