diff --git a/Cargo.toml b/Cargo.toml
index 09604565..08d35a7a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -526,6 +526,7 @@ single_match_else = "warn"
 explicit_deref_methods = "warn"
 explicit_iter_loop = "warn"
 manual_let_else = "warn"
+trivially_copy_pass_by_ref = "warn"
 
 # some sadness
 missing_errors_doc = "allow"