move solver_types to typesystem/ (because of dependencies. It should be merged with the AST really)

src/passes/8-typer-new/heuristic_break_ctor.ml

@@ -3,7 +3,7 @@
 
 open Ast_typed.Misc
 open Ast_typed.Types
-open Solver_types
+open Typesystem.Solver_types
 
 let selector :  (type_constraint_simpl, output_break_ctor) selector =
   (* find two rules with the shape x = k(var …) and x = k'(var' …) *)

src/passes/8-typer-new/heuristic_specialize1.ml

@@ -6,7 +6,7 @@
 module Core = Typesystem.Core
 open Ast_typed.Misc
 open Ast_typed.Types
-open Solver_types
+open Typesystem.Solver_types
 
 let selector : (type_constraint_simpl, output_specialize1) selector =
   (* find two rules with the shape (x = forall b, d) and x = k'(var' …) or vice versa *)

src/passes/8-typer-new/normalizer.ml

@@ -2,7 +2,7 @@ module Core = Typesystem.Core
 module Map = RedBlackTrees.PolyMap
 open Ast_typed.Misc
 open Ast_typed.Types
-open Solver_types
+open Typesystem.Solver_types
 
 (* sub-sub component: constraint normalizer: remove dupes and give structure
  * right now: union-find of unification vars

src/passes/8-typer-new/solver.ml

@@ -4,7 +4,7 @@ module Map = RedBlackTrees.PolyMap
 module Set = RedBlackTrees.PolySet
 module UF = UnionFind.Poly2
 open Ast_typed.Types
-open Solver_types
+open Typesystem.Solver_types
 
 (* sub-sub component: lazy selector (don't re-try all selectors every time)
  * For now: just re-try everytime *)

src/stages/typesystem/typesystem.ml

@@ -1,3 +1,4 @@
 module Core = Core
 module Shorthands = Shorthands
 module Misc = Misc
+module Solver_types = Solver_types