Voprf update (#255)

* Update to latest voprf

* Upgrade to Rust edition 2021

* Fix Clippy

* Remove all allocations

* Remove unnecessary `allow(type_alias_bounds)`

* Make all serialization infallible

* Remove self-dependency

* Update rustyline

src/hash.rs

@@ -7,11 +7,58 @@
 
 //! A convenience trait for digest bounds used throughout the library
 
-use digest::{BlockInput, FixedOutput, Reset, Update};
+use digest::block_buffer::Eager;
+use digest::core_api::{BlockSizeUser, BufferKindUser, CoreProxy, FixedOutputCore};
+use digest::{Digest, FixedOutputReset, HashMarker, OutputSizeUser};
+use generic_array::typenum::{IsLess, Le, NonZero, U256};
+
+pub(crate) type OutputSize<D> = <<D as CoreProxy>::Core as OutputSizeUser>::OutputSize;
+
+/// Trait to simplify requirements for [`Hash`].
+pub trait ProxyHash:
+    HashMarker + FixedOutputCore + BufferKindUser<BufferKind = Eager> + Default + Clone
+where
+    <Self as BlockSizeUser>::BlockSize: IsLess<U256>,
+    Le<<Self as BlockSizeUser>::BlockSize, U256>: NonZero,
+{
+}
+
+impl<T: HashMarker + FixedOutputCore + BufferKindUser<BufferKind = Eager> + Default + Clone>
+    ProxyHash for T
+where
+    <Self as BlockSizeUser>::BlockSize: IsLess<U256>,
+    Le<<Self as BlockSizeUser>::BlockSize, U256>: NonZero,
+{
+}
 
 /// Trait inheriting the requirements from digest::Digest for compatibility with HKDF and HMAC
 // Associated types could be simplified when they are made as defaults:
 // https://github.com/rust-lang/rust/issues/29661
-pub trait Hash: Update + BlockInput + FixedOutput + Reset + Default + Clone {}
+pub trait Hash:
+    Digest
+    + OutputSizeUser<OutputSize = OutputSize<Self>>
+    + BlockSizeUser
+    + FixedOutputReset
+    + CoreProxy
+    + Clone
+where
+    <Self as CoreProxy>::Core: ProxyHash,
+    <<Self as CoreProxy>::Core as BlockSizeUser>::BlockSize: IsLess<U256>,
+    Le<<<Self as CoreProxy>::Core as BlockSizeUser>::BlockSize, U256>: NonZero,
+{
+}
 
-impl<T: Update + BlockInput + FixedOutput + Reset + Default + Clone> Hash for T {}
+impl<
+        T: Digest
+            + OutputSizeUser<OutputSize = OutputSize<Self>>
+            + BlockSizeUser
+            + FixedOutputReset
+            + CoreProxy
+            + Clone,
+    > Hash for T
+where
+    <Self as CoreProxy>::Core: ProxyHash,
+    <<Self as CoreProxy>::Core as BlockSizeUser>::BlockSize: IsLess<U256>,
+    Le<<<Self as CoreProxy>::Core as BlockSizeUser>::BlockSize, U256>: NonZero,
+{
+}