The `isRef` check being removed here used to be an optimization, because
this structure only tracked whether ref counting operations need to be
inserted at all. Now the structure also tracks whether the value needs
to be checked for being a scalar or not, which is something that can be
refined by a `cases` arm, since inductive types can have a mix of scalar
and non-scalar constructors.
This PR removes uses of `Lean.RBMap` in Lean itself.
Furthermore some massaging of the import graph is done in order to avoid
having `Std.Data.TreeMap.AdditionalOperations` (which is quite
expensive) be the critical path for a large chunk of Lean. In particular
we can build `Lean.Meta.Simp` and `Lean.Meta.Grind` without it thanks to
these changes.
We did previously not conduct this change as `Std.TreeMap` was not
outperforming `Lean.RBMap` yet, however this has changed with the new
code generator.
This is mostly a refactoring that replaces other analyses with type
information, but due to the introduction of `tagged` it also has the
side effect of eliminating ref counting ops entirely for types that
always have a tagged scalar representation, e.g. `Unit`.
This PR modifies the signature of the functions `Nat.fold`,
`Nat.foldRev`, `Nat.any`, `Nat.all`, so that the function is passed the
upper bound. This allows us to change runtime array bounds checks to
compile time checks in many places.
@Kha I was tired of writing `arbitrary _` :)
There 0 places in the stdlib where the type needs to be provided.
If in the future we need to specify the type we can use
`arbitrary (α := <type>)`
