new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/ion/lexical-check-4.js
@@ -0,0 +1,15 @@
+var caught = false;
+try {
+    (function() {
+        let x = (function f(y) {
+            if (y == 0) {
+                x
+                return
+            }
+            return f(y - 1)
+        })(3)
+    })()
+} catch(e) {
+    caught = true;
+}
+assertEq(caught, true);

--- a/js/src/jit/MIR.h
+++ b/js/src/jit/MIR.h
@@ -7048,16 +7048,17 @@ class MLexicalCheck
     public BoxPolicy<0>::Data
 {
     explicit MLexicalCheck(MDefinition *input)
       : MUnaryInstruction(input)
     {
         setResultType(MIRType_Value);
         setResultTypeSet(input->resultTypeSet());
         setMovable();
+        setGuard();
     }
 
   public:
     INSTRUCTION_HEADER(LexicalCheck)
 
     static MLexicalCheck *New(TempAllocator &alloc, MDefinition *input) {
         return new(alloc) MLexicalCheck(input);
     }