From c063641ab0c32ab19715342a4856ed040a1fde14 Mon Sep 17 00:00:00 2001
From: "Yukihiro \"Matz\" Matsumoto" <matz@ruby-lang.org>
Date: Mon, 10 Apr 2017 08:21:03 +0900
Subject: Clear local (but non-argument) variables in OP_ENTER.

Otherwise, the following script prints an uninitialized value.

def f(*a)
  if false
    b = 15
  end
  p b
end
f(1,2,3)
---
 src/vm.c | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'src')

diff --git a/src/vm.c b/src/vm.c
index 0fba22c2c..49f10c5a5 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -1637,6 +1637,10 @@ RETRY_TRY_BLOCK:
         }
         pc += o + 1;
       }
+      /* clear local (but non-argument) variables */
+      if (irep->nlocals-len-2 > 0) {
+        stack_clear(&regs[len+2], irep->nlocals-len-2);
+      }
       JUMP;
     }
 
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