Fixed a bug where as patterns weren't binding their variable correctly

2 files changed, 8 insertions, 1 deletions

diff --git a/src/type_check.ml b/src/type_check.ml
index 0a2c0dcb..87f65dcc 100644
--- a/src/type_check.ml
+++ b/src/type_check.ml
@@ -1968,7 +1968,7 @@ and infer_pat env (P_aux (pat_aux, (l, ())) as pat) =
      annot_pat (P_vector_concat (inferred_pat :: inferred_pats)) (lvector_typ env len vtyp), env
   | P_as (pat, id) ->
      let (typed_pat, env) = infer_pat env pat in
-     annot_pat (P_as (typed_pat, id)) (pat_typ_of typed_pat), env
+     annot_pat (P_as (typed_pat, id)) (pat_typ_of typed_pat), Env.add_local id (Immutable, pat_typ_of typed_pat) env
   | _ -> typ_error l ("Couldn't infer type of pattern " ^ string_of_pat pat)
 
 and bind_assignment env (LEXP_aux (lexp_aux, _) as lexp) (E_aux (_, (l, ())) as exp) =
diff --git a/test/typecheck/pass/as_pattern.sail b/test/typecheck/pass/as_pattern.sail
new file mode 100644
index 00000000..a1cd9461
--- /dev/null
+++ b/test/typecheck/pass/as_pattern.sail
@@ -0,0 +1,7 @@
+
+val int -> int effect pure test
+
+function test ((int) _ as x) =
+{
+  x
+}