diff --git a/src/test/codegen/internalize-closures.rs b/src/test/codegen/internalize-closures.rs
index 8d9192c6fa0..ab3dc3fba5e 100644
--- a/src/test/codegen/internalize-closures.rs
+++ b/src/test/codegen/internalize-closures.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Zmir-opt-level=0
 
 pub fn main() {