From 01b061f0082a70f66016e78075a5952af8ed5431 Mon Sep 17 00:00:00 2001
From: Guillaume Melquiond
Date: Tue, 23 Mar 2021 10:20:10 +0100
Subject: Do not match on record types with mutable fields in function
 arguments.

This tends to confuse the OCaml compiler, for good reasons. Indeed, if
there are mutable fields, the generated code cannot wait for the function
to be fully applied. It needs to recover the value of the mutable fields
as early as possible, and thus to create a closure.

Example:

    let foo {bar} x = ...

is compiled as

    let foo y = match y with {bar} -> fun x -> ...
---
 plugins/extraction/mlutil.ml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

(limited to 'plugins/extraction')

diff --git a/plugins/extraction/mlutil.ml b/plugins/extraction/mlutil.ml
index da4a50b674..cfdaac710b 100644
--- a/plugins/extraction/mlutil.ml
+++ b/plugins/extraction/mlutil.ml
@@ -217,13 +217,13 @@ module Mlenv = struct
 
   (* Adding a type with no [Tvar], hence no generalization needed. *)
 
-  let push_type {env=e;free=f} t =
-    { env = (0,t) :: e; free = find_free f t}
+  let push_type mle t =
+    { env = (0,t) :: mle.env; free = find_free mle.free t}
 
   (* Adding a type with no [Tvar] nor [Tmeta]. *)
 
-  let push_std_type {env=e;free=f} t =
-    { env = (0,t) :: e; free = f}
+  let push_std_type mle t =
+    { env = (0,t) :: mle.env; free = mle.free}
 
 end
 
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