diff --git a/cranelift/src/clif-util.rs b/cranelift/src/clif-util.rs
index 86e892420a..7db013a023 100644
--- a/cranelift/src/clif-util.rs
+++ b/cranelift/src/clif-util.rs
@@ -1,5 +1,5 @@
-#![deny(trivial_numeric_casts)]
-#![warn(unused_import_braces, unstable_features, unused_extern_crates)]
+#![deny(trivial_numeric_casts, unused_extern_crates, unstable_features)]
+#![warn(unused_import_braces)]
 #![cfg_attr(
     feature = "cargo-clippy",
     warn(
diff --git a/lib/codegen/src/lib.rs b/lib/codegen/src/lib.rs
index 5ae6812a52..2d740668f6 100644
--- a/lib/codegen/src/lib.rs
+++ b/lib/codegen/src/lib.rs
@@ -2,7 +2,7 @@
 
 #![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
 #![warn(unused_import_braces)]
-#![cfg_attr(feature = "std", warn(unstable_features))]
+#![cfg_attr(feature = "std", deny(unstable_features))]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature="cargo-clippy", allow(
 // This requires Rust 1.27 or later.
diff --git a/lib/entity/src/lib.rs b/lib/entity/src/lib.rs
index cb1c248db1..dd666c6ac7 100644
--- a/lib/entity/src/lib.rs
+++ b/lib/entity/src/lib.rs
@@ -31,7 +31,7 @@
 
 #![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
 #![warn(unused_import_braces)]
-#![cfg_attr(feature = "std", warn(unstable_features))]
+#![cfg_attr(feature = "std", deny(unstable_features))]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
 #![cfg_attr(
diff --git a/lib/faerie/src/lib.rs b/lib/faerie/src/lib.rs
index 14397afbd0..078488a953 100644
--- a/lib/faerie/src/lib.rs
+++ b/lib/faerie/src/lib.rs
@@ -2,8 +2,8 @@
 //!
 //! Users of this module should not have to depend on faerie directly.
 
-#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
-#![warn(unused_import_braces, unstable_features)]
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates, unstable_features)]
+#![warn(unused_import_braces)]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
 #![cfg_attr(
diff --git a/lib/filetests/src/lib.rs b/lib/filetests/src/lib.rs
index b052253e67..da665a6f2b 100644
--- a/lib/filetests/src/lib.rs
+++ b/lib/filetests/src/lib.rs
@@ -3,8 +3,8 @@
 //! This crate contains the main test driver as well as implementations of the
 //! available filetest commands.
 
-#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
-#![warn(unused_import_braces, unstable_features)]
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates, unstable_features)]
+#![warn(unused_import_braces)]
 #![cfg_attr(feature = "cargo-clippy",
     allow(
           type_complexity,
diff --git a/lib/frontend/src/lib.rs b/lib/frontend/src/lib.rs
index be19ebc2be..7fca5ae122 100644
--- a/lib/frontend/src/lib.rs
+++ b/lib/frontend/src/lib.rs
@@ -129,7 +129,7 @@
 
 #![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
 #![warn(unused_import_braces)]
-#![cfg_attr(feature = "std", warn(unstable_features))]
+#![cfg_attr(feature = "std", deny(unstable_features))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default))]
 #![cfg_attr(
     feature = "cargo-clippy",
diff --git a/lib/module/src/lib.rs b/lib/module/src/lib.rs
index a7676c4a8c..45e3bd683e 100644
--- a/lib/module/src/lib.rs
+++ b/lib/module/src/lib.rs
@@ -2,7 +2,7 @@
 
 #![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
 #![warn(unused_import_braces)]
-#![cfg_attr(feature = "std", warn(unstable_features))]
+#![cfg_attr(feature = "std", deny(unstable_features))]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
 #![cfg_attr(
diff --git a/lib/native/src/lib.rs b/lib/native/src/lib.rs
index 5439d743cc..3d4e4bac2c 100644
--- a/lib/native/src/lib.rs
+++ b/lib/native/src/lib.rs
@@ -1,8 +1,8 @@
 //! Performs autodetection of the host for the purposes of running
 //! Cranelift to generate code to run on the same machine.
 
-#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
-#![warn(unused_import_braces, unstable_features)]
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates, unstable_features)]
+#![warn(unused_import_braces)]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
 #![cfg_attr(
diff --git a/lib/reader/src/lib.rs b/lib/reader/src/lib.rs
index edac07622f..2873a644ac 100644
--- a/lib/reader/src/lib.rs
+++ b/lib/reader/src/lib.rs
@@ -3,8 +3,8 @@
 //! The `cranelift_reader` library supports reading .clif files. This functionality is needed for
 //! testing Cranelift, but is not essential for a JIT compiler.
 
-#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
-#![warn(unused_import_braces, unstable_features)]
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates, unstable_features)]
+#![warn(unused_import_braces)]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
 #![cfg_attr(
diff --git a/lib/serde/src/clif-json.rs b/lib/serde/src/clif-json.rs
index 659bc818a8..9c3338e600 100644
--- a/lib/serde/src/clif-json.rs
+++ b/lib/serde/src/clif-json.rs
@@ -1,7 +1,7 @@
 //! Utility for `cranelift_serde`.
 
-#![deny(trivial_numeric_casts)]
-#![warn(unused_import_braces, unstable_features, unused_extern_crates)]
+#![deny(trivial_numeric_casts, unused_extern_crates, unstable_features)]
+#![warn(unused_import_braces)]
 #![cfg_attr(
     feature = "cargo-clippy",
     warn(
diff --git a/lib/simplejit/src/lib.rs b/lib/simplejit/src/lib.rs
index 01dd0938f0..99297f33b0 100644
--- a/lib/simplejit/src/lib.rs
+++ b/lib/simplejit/src/lib.rs
@@ -1,7 +1,7 @@
 //! Top-level lib.rs for `cranelift_simplejit`.
 
-#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
-#![warn(unused_import_braces, unstable_features)]
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates, unstable_features)]
+#![warn(unused_import_braces)]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
 #![cfg_attr(
diff --git a/lib/umbrella/src/lib.rs b/lib/umbrella/src/lib.rs
index ad241483e7..4faeabdd8a 100644
--- a/lib/umbrella/src/lib.rs
+++ b/lib/umbrella/src/lib.rs
@@ -1,7 +1,7 @@
 //! Cranelift umbrella crate, providing a convenient one-line dependency.
 
-#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
-#![warn(unused_import_braces, unstable_features)]
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates, unstable_features)]
+#![warn(unused_import_braces)]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
 #![cfg_attr(
diff --git a/lib/wasm/src/lib.rs b/lib/wasm/src/lib.rs
index 1711a351ab..a559ae941d 100644
--- a/lib/wasm/src/lib.rs
+++ b/lib/wasm/src/lib.rs
@@ -11,7 +11,7 @@
 
 #![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
 #![warn(unused_import_braces)]
-#![cfg_attr(feature = "std", warn(unstable_features))]
+#![cfg_attr(feature = "std", deny(unstable_features))]
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
 #![cfg_attr(