From 01d2b498ba47113f0d10fbd734c7dd99e3a39c76 Mon Sep 17 00:00:00 2001
From: Son Ho
Date: Sat, 7 Jan 2023 11:07:18 +0100
Subject: Improve PureMicroPasses.filter_useless and regenerate the betree code

---
 compiler/PureMicroPasses.ml | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'compiler/PureMicroPasses.ml')

diff --git a/compiler/PureMicroPasses.ml b/compiler/PureMicroPasses.ml
index 25d760fe..b9441397 100644
--- a/compiler/PureMicroPasses.ml
+++ b/compiler/PureMicroPasses.ml
@@ -828,6 +828,14 @@ let filter_useless (filter_monadic_calls : bool) (ctx : trans_ctx)
             let dont_filter () =
               let re, used_re = self#visit_texpression env re in
               let used = VarId.Set.union used (used_re ()) in
+              (* Simplify the left pattern if it only contains dummy variables *)
+              let lv =
+                if all_dummies then
+                  let ty = lv.ty in
+                  let value = PatDummy in
+                  { value; ty }
+                else lv
+              in
               (Let (monadic, lv, re, e), fun _ -> used)
             in
             (* Potentially filter the let-binding *)
-- 
cgit v1.2.3