A table used for freshening of identifiers in
Move_within_set_of_closures ("ids of closures"); and
Project_var ("bound vars of closures") expressions.
This information is propagated bottom up and populated when inlining a function containing a closure declaration.
let f x =
let g y = ... x ... in
... g.x ... (Project_var x)
... g 1 ... (Apply (Project_closure g ...))
If f is inlined, g is renamed. The approximation of g will carry this table such that later the access to the field x of g and selection of g in the closure can be substituted.
val empty : t
Freshen a closure ID based on the given renaming. The same ID is returned if the renaming does not affect it. If dealing with approximations, you probably want to use
Simple_value_approx.freshen_and_check_closure_id instead of this function.
apply_closure_id, but for variables within closures.