Summary:
To meet the pure parts of formulas, the process was to (a) call Rename.extend
with variables occuring in similar places and (b) extract substitutions out of
those. Two matching primed vars would both be replaced by some fresh primed var.
However, equivalence classes of primed variables would *not* be replaced by
one fresh (primed) variable. Now, that should work.
Reviewed By: mbouaziz
Differential Revision: D14150192
fbshipit-source-id: 90ca9216c
Radu Grigore