From aa9cd4a395b84bc2f41152a28cd53bf80214f8fd Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Thu, 24 Oct 2019 19:39:34 +0200
Subject: [PATCH] core: formal_p: Prepare for M2-Planet.

* src/eval-apply.c (formal_p): Prepare for M2-Planet.
---
 src/eval-apply.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/eval-apply.c b/src/eval-apply.c
index 5f137e4e..33cd2d90 100644
--- a/src/eval-apply.c
+++ b/src/eval-apply.c
@@ -213,8 +213,12 @@ formal_p (SCM x, SCM formals)   /*:((internal)) */
       else
         return cell_f;
     }
-  while (TYPE (formals) == TPAIR && CAR (formals) != x)
-    formals = CDR (formals);
+  while (TYPE (formals) == TPAIR)
+    {
+      if (CAR (formals) == x)
+        break;
+      formals = CDR (formals);
+    }
   if (TYPE (formals) == TSYMBOL)
     return formals == x;
   return TYPE (formals) == TPAIR;