diff --git a/src/test/ui/auxiliary/rustc-rust-log-aux.rs b/src/test/ui/auxiliary/rustc-rust-log-aux.rs
new file mode 100644
index 00000000000..daa8e9f495e
--- /dev/null
+++ b/src/test/ui/auxiliary/rustc-rust-log-aux.rs
@@ -0,0 +1 @@
+// rustc-env:RUSTC_LOG=debug
diff --git a/src/test/ui/rustc-rust-log.rs b/src/test/ui/rustc-rust-log.rs
index 1c4252b23ea..8ceb24dd2af 100644
--- a/src/test/ui/rustc-rust-log.rs
+++ b/src/test/ui/rustc-rust-log.rs
@@ -8,7 +8,7 @@
 // dont-check-compiler-stdout
 // dont-check-compiler-stderr
 // compile-flags: --error-format human
-
+// aux-build: rustc-rust-log-aux.rs
 // rustc-env:RUSTC_LOG=debug
 
 fn main() {}