Fix: Don't remove uncalled polymorphic constructors if they are matched upon

Previously the specialization would remove any polymorphic union
constructor that was never created anywhere in the
specification. While this wasn't usually problematic, it does leave an
edge case where such a constructor could be matched upon in a pattern,
and then the resulting match would fail to compile as it would be
matching on a constructor kind that doesn't exists.

This should fix that issue by chaging the V_ctor_kind value into an
F_ctor_kind fragment. Previously a polymorphic constructor-kind would
have been represented by its mangled name, e.g.

V_ctor_kind "zSome_unit"

would now be represented as

V_ctor_kind ("Some", unifiers, ty)

where ty is a monomorphic version of the original constructor's type
such that

ctyp_unify original_ty ty = unifiers

and the mangled name we generate is

zencode_string ("Some_" ^ string_of_list "_" string_of_ctyp unifiers)

1 files changed, 1 insertions, 0 deletions

diff --git a/language/jib.ott b/language/jib.ott
index 4f8eeacc..e26389ce 100644
--- a/language/jib.ott
+++ b/language/jib.ott
@@ -60,6 +60,7 @@ fragment :: 'F_' ::=
   | name                                   :: :: id
   | '&' name                               :: :: ref
   | value                                  :: :: lit
+  | kind id ( ctyp0 , ... , ctypn ) ctyp   :: :: ctor_kind
   | fragment op fragment'                  :: :: op
   | op fragment                            :: :: unary
   | string ( fragment0 , ... , fragmentn ) :: :: call