diff --git a/test-cargo-miri/subcrate/src/lib.rs b/test-cargo-miri/subcrate/src/lib.rs
index 07ed1acb7a05..2ccb6704b05e 100644
--- a/test-cargo-miri/subcrate/src/lib.rs
+++ b/test-cargo-miri/subcrate/src/lib.rs
@@ -1,5 +1,5 @@
 #[cfg(doctest)]
-use num_cpus as _;
+compile_error!("rustdoc should not touch me");
 
 #[cfg(test)]
 compile_error!("Miri should not touch me");