diff --git a/tests/lean/run/IO3.lean b/tests/lean/run/IO3.lean
index b9b42c1077..cb261641d0 100644
--- a/tests/lean/run/IO3.lean
+++ b/tests/lean/run/IO3.lean
@@ -1,5 +1,4 @@
 import system.IO
-open string
 
 definition main : IO unit :=
 do { l ← get_line,