lints: Warn rather than deny by default

We check with `-Dwarnings` in CI, so these still get checked. This
change serves to prevent failures to compile downstream if the lint
expectations are not met on untested targets.

Author: tgross35

src/lib.rs

@@ -22,8 +22,8 @@
 #![cfg_attr(feature = "rustc-dep-of-std", feature(link_cfg, no_core))]
 #![cfg_attr(feature = "rustc-dep-of-std", allow(internal_features))]
 // Enable extra lints:
-#![cfg_attr(feature = "extra_traits", deny(missing_debug_implementations))]
-#![deny(missing_copy_implementations, safe_packed_borrows)]
+#![cfg_attr(feature = "extra_traits", warn(missing_debug_implementations))]
+#![warn(missing_copy_implementations, safe_packed_borrows)]
 #![cfg_attr(not(feature = "rustc-dep-of-std"), no_std)]
 #![cfg_attr(feature = "rustc-dep-of-std", no_core)]