diff --git a/substrate/core/primitives/src/lib.rs b/substrate/core/primitives/src/lib.rs
index 09b4e9a49e..e52d7b9490 100644
--- a/substrate/core/primitives/src/lib.rs
+++ b/substrate/core/primitives/src/lib.rs
@@ -21,6 +21,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 #![cfg_attr(not(feature = "std"), feature(alloc))]
 
+/// Initalise a key-value collection from array.
+///
 /// Creates a vector of given pairs and calls `collect` on the iterator from it.
 /// Can be used to create a `HashMap`.
 #[macro_export]
diff --git a/substrate/core/sr-primitives/src/lib.rs b/substrate/core/sr-primitives/src/lib.rs
index cf820b3fbd..6621c693ae 100644
--- a/substrate/core/sr-primitives/src/lib.rs
+++ b/substrate/core/sr-primitives/src/lib.rs
@@ -62,6 +62,8 @@ pub type RuntimeString = &'static str;
 macro_rules! create_runtime_str {
 	( $y:expr ) => {{ ::std::borrow::Cow::Borrowed($y) }}
 }
+
+/// Create a const [RuntimeString].
 #[cfg(not(feature = "std"))]
 #[macro_export]
 macro_rules! create_runtime_str {
@@ -319,6 +321,7 @@ pub fn verify_encoded_lazy<V: Verify, T: codec::Encode>(sig: &V, item: &T, signe
 	)
 }
 
+/// Helper macro for `impl_outer_config`
 #[macro_export]
 macro_rules! __impl_outer_config_types {
 	(
diff --git a/substrate/srml/council/src/lib.rs b/substrate/srml/council/src/lib.rs
index c630c587d3..3eca2ffca0 100644
--- a/substrate/srml/council/src/lib.rs
+++ b/substrate/srml/council/src/lib.rs
@@ -26,7 +26,7 @@ extern crate serde;
 extern crate hex_literal;
 
 extern crate parity_codec as codec;
-#[macro_use] extern crate parity_codec_derive;
+extern crate parity_codec_derive;
 extern crate substrate_primitives;
 extern crate sr_std as rstd;
 extern crate sr_io as runtime_io;
diff --git a/substrate/srml/example/src/lib.rs b/substrate/srml/example/src/lib.rs
index cfad2f4997..3dae6d729b 100644
--- a/substrate/srml/example/src/lib.rs
+++ b/substrate/srml/example/src/lib.rs
@@ -36,7 +36,6 @@ extern crate substrate_primitives;
 extern crate sr_primitives;
 
 // Needed for deriving `Encode` and `Decode` for `RawEvent`.
-#[macro_use]
 extern crate parity_codec_derive;
 extern crate parity_codec as codec;
 
diff --git a/substrate/srml/executive/src/lib.rs b/substrate/srml/executive/src/lib.rs
index 6646b229b8..e9a46dfff3 100644
--- a/substrate/srml/executive/src/lib.rs
+++ b/substrate/srml/executive/src/lib.rs
@@ -19,7 +19,6 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #[cfg(test)]
-#[macro_use]
 extern crate parity_codec_derive;
 
 #[cfg_attr(test, macro_use)]
diff --git a/substrate/srml/session/src/lib.rs b/substrate/srml/session/src/lib.rs
index 032b3328a3..4e22a59dbe 100644
--- a/substrate/srml/session/src/lib.rs
+++ b/substrate/srml/session/src/lib.rs
@@ -24,7 +24,6 @@ extern crate sr_std as rstd;
 #[macro_use]
 extern crate srml_support as runtime_support;
 
-#[macro_use]
 extern crate parity_codec_derive;
 
 #[cfg(test)]
diff --git a/substrate/srml/sudo/src/lib.rs b/substrate/srml/sudo/src/lib.rs
index 63591aba88..3ea2dda8d7 100644
--- a/substrate/srml/sudo/src/lib.rs
+++ b/substrate/srml/sudo/src/lib.rs
@@ -25,7 +25,6 @@ extern crate sr_io;
 #[cfg(test)]
 extern crate substrate_primitives;
 extern crate sr_primitives;
-#[macro_use]
 extern crate parity_codec_derive;
 extern crate parity_codec as codec;
 #[macro_use]
diff --git a/substrate/srml/upgrade-key/src/lib.rs b/substrate/srml/upgrade-key/src/lib.rs
index 1b10d3a3d3..ab46321d8e 100644
--- a/substrate/srml/upgrade-key/src/lib.rs
+++ b/substrate/srml/upgrade-key/src/lib.rs
@@ -25,7 +25,6 @@ extern crate sr_io;
 #[cfg(test)]
 extern crate substrate_primitives;
 extern crate sr_primitives;
-#[macro_use]
 extern crate parity_codec_derive;
 extern crate parity_codec as codec;
 #[macro_use]