1 files changed, 2 insertions, 1 deletions
diff --git a/src/main/java/org/zwobble/couscous/interpreter/Environment.java b/src/main/java/org/zwobble/couscous/interpreter/Environment.java
index ef91916..a3b3871 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Environment.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Environment.java
@@ -1,5 +1,6 @@
 package org.zwobble.couscous.interpreter;
 
+import java.util.HashMap;
 import java.util.Map;
 
 import org.zwobble.couscous.values.InterpreterValue;
@@ -8,7 +9,7 @@ public class Environment {
     private Map<Integer, InterpreterValue> stackFrame;
 
     public Environment(Map<Integer, InterpreterValue> stackFrame) {
-        this.stackFrame = stackFrame;
+        this.stackFrame = new HashMap<>(stackFrame);
     }
 
     public InterpreterValue get(int referentId) {