diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index c76cba824a373..759486a09502e 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -810,6 +810,7 @@ const DIAGNOSTICS_DIRECTIVE_NAMES: &[&str] = &[
     "only-sparc",
     "only-sparc64",
     "only-thumb",
+    "only-unix",
     "only-wasm32",
     "only-wasm32-bare",
     "only-windows",