From: Mark Thom <markjordanthom@gmail.com>
Date: Fri, 13 Jan 2023 06:46:57 +0000 (-0700)
Subject: tighten deallocate truncation of stack (#1686)
X-Git-Tag: v0.9.2~237
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=3a4aa2a54127e2b633aadabf2f75930e6d0f1dbf;p=scryer-prolog.git

tighten deallocate truncation of stack (#1686)
---

diff --git a/src/machine/machine_state_impl.rs b/src/machine/machine_state_impl.rs
index 00e17649..a77fda72 100644
--- a/src/machine/machine_state_impl.rs
+++ b/src/machine/machine_state_impl.rs
@@ -2784,8 +2784,11 @@ impl MachineState {
         self.cp = frame.prelude.cp;
         self.e = frame.prelude.e;
 
-        if e > self.b {
-            self.stack.truncate(e);
+        if self.e > self.b {
+            let frame = self.stack.index_and_frame(self.e);
+            let size = AndFrame::size_of(frame.prelude.univ_prelude.num_cells);
+
+            self.stack.truncate(self.e + size);
         }
 
         self.p += 1;