diff --git a/compiler/src/parsing/parser_header.re b/compiler/src/parsing/parser_header.re
index 789d6959d..435b625d6 100644
--- a/compiler/src/parsing/parser_header.re
+++ b/compiler/src/parsing/parser_header.re
@@ -34,33 +34,6 @@ let to_loc = ((loc_start, loc_end)) => {
   {loc_start, loc_end, loc_ghost: false};
 };
 
-let fix_tyvar_mapper = super => {
-  open Ast_mapper;
-  open Ast_helper;
-  let typ = (mapper, {ptyp_desc, ptyp_loc} as t) =>
-    switch (ptyp_desc) {
-    | PTyVar(v)
-        when
-          v != ""
-          && (
-            switch (v.[0]) {
-            | 'A' .. 'Z' => true
-            | _ => false
-            }
-          ) =>
-      let id = mkloc(IdentName(mkloc(v, ptyp_loc)), ptyp_loc);
-      {...t, ptyp_desc: PTyConstr(id, [])};
-    | _ => super.typ(mapper, t)
-    };
-  {...super, typ};
-};
-
-let fix_blocks = ({statements} as prog) => {
-  open Ast_mapper;
-  let mapper = default_mapper |> fix_tyvar_mapper;
-  {...prog, statements: List.map(mapper.toplevel(mapper), statements)};
-};
-
 let mkid = ns => {
   let help = ns => {
     let rec help = (ns, (acc_ident, acc_str)) => {
@@ -122,7 +95,7 @@ let make_program = (~loc, module_name, statements) => {
   let loc_start = {...loc.loc_start, pos_lnum: 1, pos_cnum: 0, pos_bol: 0};
   let prog_loc = {...loc, loc_start};
 
-  fix_blocks({module_name, statements, comments: [], prog_loc});
+  {module_name, statements, comments: [], prog_loc};
 };
 
 let parse_program = (program, token, lexbuf) => {