Use crate::prelude::* rather than specific imports

New rustc beta now warns on duplicate imports when one of the
imports is from a wildcard import or the default prelude. Thus, to
avoid this here we prefer to always use `crate::prelude::*` and let
it decide if we actually need to import anything.

Author: TheBlueMatt

lightning-invoice/src/de.rs

@@ -1,5 +1,6 @@
 #[cfg(feature = "std")]
 use std::error;
+#[cfg(not(feature = "std"))]
 use core::convert::TryFrom;
 use core::fmt;
 use core::fmt::{Display, Formatter};

lightning-invoice/src/utils.rs

@@ -19,6 +19,7 @@ use secp256k1::PublicKey;
 use alloc::collections::{btree_map, BTreeMap};
 use core::ops::Deref;
 use core::time::Duration;
+#[cfg(not(feature = "std"))]
 use core::iter::Iterator;
 
 /// Utility to create an invoice that can be paid to one of multiple nodes, or a "phantom invoice."

lightning/src/blinded_path/payment.rs

@@ -17,8 +17,6 @@ use crate::util::ser::{HighZeroBytesDroppedBigSize, Readable, Writeable, Writer}
 #[allow(unused_imports)]
 use crate::prelude::*;
 
-use core::convert::TryFrom;
-
 /// An intermediate node, its outbound channel, and relay parameters.
 #[derive(Clone, Debug)]
 pub struct ForwardNode {

lightning/src/chain/chaininterface.rs

@@ -14,7 +14,8 @@
 //! disconnections, transaction broadcasting, and feerate information requests.
 
 use core::{cmp, ops::Deref};
-use core::convert::TryInto;
+
+use crate::prelude::*;
 
 use bitcoin::blockdata::transaction::Transaction;
 

lightning/src/chain/channelmonitor.rs

@@ -58,7 +58,6 @@ use crate::prelude::*;
 
 use core::{cmp, mem};
 use crate::io::{self, Error};
-use core::convert::TryInto;
 use core::ops::Deref;
 use crate::sync::{Mutex, LockTestExt};
 

lightning/src/chain/package.rs

@@ -36,7 +36,6 @@ use crate::util::ser::{Readable, Writer, Writeable, RequiredWrapper};
 
 use crate::io;
 use core::cmp;
-use core::convert::TryInto;
 use core::mem;
 use core::ops::Deref;
 

lightning/src/crypto/chacha20.rs

@@ -12,7 +12,6 @@
 #[cfg(not(fuzzing))]
 mod real_chacha {
 	use core::cmp;
-	use core::convert::TryInto;
 
 	#[derive(Clone, Copy, PartialEq, Eq)]
 	#[allow(non_camel_case_types)]
@@ -335,11 +334,10 @@ pub use self::fuzzy_chacha::ChaCha20;
 
 #[cfg(test)]
 mod test {
-	use alloc::vec;
-	use alloc::vec::{Vec};
-	use core::convert::TryInto;
 	use core::iter::repeat;
 
+	use crate::prelude::*;
+
 	use super::ChaCha20;
 
 	#[test]

lightning/src/crypto/poly1305.rs

@@ -8,7 +8,8 @@
 // https://github.com/floodyberry/poly1305-donna
 
 use core::cmp::min;
-use core::convert::TryInto;
+
+use crate::prelude::*;
 
 #[derive(Clone, Copy)]
 pub struct Poly1305 {
@@ -206,7 +207,6 @@ impl Poly1305 {
 #[cfg(test)]
 mod test {
 	use core::iter::repeat;
-	use alloc::vec::Vec;
 
 	use super::Poly1305;
 

lightning/src/lib.rs

@@ -165,12 +165,15 @@ mod io_extras {
 }
 
 mod prelude {
+	#![allow(unused_imports)]
+
 	pub use alloc::{vec, vec::Vec, string::String, collections::VecDeque, boxed::Box};
 
 	pub use alloc::borrow::ToOwned;
 	pub use alloc::string::ToString;
 
-	pub use core::convert::{TryFrom, TryInto};
+	pub use core::convert::{AsMut, AsRef, TryFrom, TryInto};
+	pub use core::default::Default;
 	pub use core::marker::Sized;
 
 	pub(crate) use crate::util::hash_tables::*;

lightning/src/ln/channel.rs

@@ -50,7 +50,6 @@ use crate::util::scid_utils::scid_from_parts;
 use crate::io;
 use crate::prelude::*;
 use core::{cmp,mem,fmt};
-use core::convert::TryInto;
 use core::ops::Deref;
 #[cfg(any(test, fuzzing, debug_assertions))]
 use crate::sync::Mutex;