* refactor: refactor concretize module
This commit primarily refactors the concretize module, breaking out the
local definitions for visit functions into top level functions that are
hopefully easier to change. I've also modified some monadic code in the
interest of terseness.
This commit adds some additional patterns for XObj forms as well.
* refactor: Only export called functions in Concretize
Adds an export list to Concretize so that the module encapsulates those
functions that are only used internally within the module.
* refactor: better names in concretize functions
Clarify the names of variables in visitor type functions.
* refactor: ensure findType returns a type
Adds an additional check to findType that ensures the retrieved binder
is in fact a type and not another object. This is necessary for certain
contexts like type concretization since modules may also be designated
by symbols that refer to types.
* fix: ensure nested polymorphic types are emitted
This commit fixes an issue whereby nested polymorphic types would not be
emitted by the compiler, even though their member functions were
emitted.
In order to support this, we need to update a couple of functions to
take the global environment (to find nested types, which live in
modules) in addition to the top level type environment. Additionally, we
had to update scoring to account for nested names.
fixes#1293
* test: add tests for nested polymorphic types
Adds regression tests to ensure nested polymorphic types are concretized
and emitted correctly.