Module Extract_projections

Identify projections from variables used in function bodies (free variables or specialised args, for example, according to which_variables below). Projections from variables that are also used boxed are not returned.

which_variables maps (existing) inner variables to (existing) outer variables in the manner of free_vars and specialised_args in Flambda.set_of_closures.

The returned projections are projecting_from (cf. projection.mli) the "existing inner vars".