diff --git a/poincare/include/poincare/tree_by_reference.h b/poincare/include/poincare/tree_by_reference.h
index 9060c54b0..0b785116c 100644
--- a/poincare/include/poincare/tree_by_reference.h
+++ b/poincare/include/poincare/tree_by_reference.h
@@ -83,11 +83,7 @@ public:
   // Replace
   void replaceWithInPlace(TreeByReference t);
   void replaceChildInPlace(TreeByReference oldChild, TreeByReference newChild);
-  void replaceChildAtIndexInPlace(int oldChildIndex, TreeByReference newChild) {
-    assert(oldChildIndex >= 0 && oldChildIndex < numberOfChildren());
-    TreeByReference oldChild = childAtIndex(oldChildIndex);
-    replaceChildInPlace(oldChild, newChild);
-  }
+  void replaceChildAtIndexInPlace(int oldChildIndex, TreeByReference newChild);
   void replaceWithAllocationFailureInPlace(int currentNumberOfChildren);
   void replaceChildWithGhostInPlace(TreeByReference t);
   // Merge
diff --git a/poincare/src/tree_by_reference.cpp b/poincare/src/tree_by_reference.cpp
index 45a3ad043..378c6fae0 100644
--- a/poincare/src/tree_by_reference.cpp
+++ b/poincare/src/tree_by_reference.cpp
@@ -86,6 +86,18 @@ void TreeByReference::replaceChildInPlace(TreeByReference oldChild, TreeByRefere
   oldChild.node()->release(oldChild.numberOfChildren());
 }
 
+void TreeByReference::replaceChildAtIndexInPlace(int oldChildIndex, TreeByReference newChild) {
+  if (oldChildIndex < 0 || oldChildIndex >= numberOfChildren()) {
+    /* The only case where the index might be out of range is when a tree has
+     * become an allocation failure, in which case we need to escape the invalid
+     * child removal. */
+    assert(isAllocationFailure());
+    return;
+  }
+  TreeByReference oldChild = childAtIndex(oldChildIndex);
+  replaceChildInPlace(oldChild, newChild);
+}
+
 void TreeByReference::replaceWithAllocationFailureInPlace(int currentNumberOfChildren) {
   if (isAllocationFailure()) {
     return;
@@ -219,7 +231,13 @@ void TreeByReference::addChildAtIndexInPlace(TreeByReference t, int index, int c
 
 void TreeByReference::removeChildAtIndexInPlace(int i) {
   assert(!isUninitialized());
-  assert(i >= 0 && i < numberOfChildren());
+  if (i < 0 || i >= numberOfChildren()) {
+    /* The only case where the index might be out of range is when a tree has
+     * become an allocation failure, in which case we need to escape the invalid
+     * child removal. */
+    assert(isAllocationFailure());
+    return;
+  }
   TreeByReference t = childAtIndex(i);
   removeChildInPlace(t, t.numberOfChildren());
 }