chore: clippy lints (#737)

Fixes KILTprotocol/ticket#3325.

Add some basic lints (can always be expanded for either runtime-specific
code or all code via the configurable rustc flags in the new config
file). I updated the code to address all places in which the new lints
generate an error, including all weight files and weight templates. I
also updated the CI check step to check for the specific WASM-targeted,
no-std code that will be part of our runtime.

## How to test

To check runtime code against the new lint, just run the same command as
in the check workflow file:

`cargo clippy --locked --target wasm32-unknown-unknown
--no-default-features --workspace --exclude kilt-parachain --exclude
standalone-node --exclude xcm-integration-tests --exclude
'dip-provider*' --exclude 'dip-consumer*'`

Author: ntn-x2

.cargo/config.toml

@@ -0,0 +1,26 @@
+# Deployment runtime lints
+[target.'cfg(all(target_arch = "wasm32", not(test)))']
+rustflags = [
+  "-Dclippy::arithmetic_side_effects",
+  "-Dclippy::as_conversions",
+  "-Dclippy::assertions_on_result_states",
+  "-Dclippy::cast_possible_wrap",
+  "-Dclippy::dbg_macro",
+  "-Dclippy::expect_used",
+  "-Dclippy::float_arithmetic",
+  "-Dclippy::float_cmp_const",
+  "-Dclippy::index_refutable_slice",
+  "-Dclippy::indexing_slicing",
+  "-Dclippy::lossy_float_literal",
+  "-Dclippy::panic",
+  "-Dclippy::string_slice",
+  "-Dclippy::todo",
+  "-Dclippy::unimplemented",
+  "-Dclippy::unreachable",
+  "-Dclippy::unwrap_used",
+  "-Funsafe_code",
+  "-Wclippy::integer_division",
+  "-Wclippy::modulo_arithmetic",
+  "-Wclippy::print_stderr",
+  "-Wclippy::print_stdout",
+]

.github/workflows/check-code.yml

@@ -46,9 +46,13 @@ jobs:
 
     strategy:
       matrix:
-        features:
-          -
-          - --all-features
+        cargo-flags:
+          # Generic clippy checks for all features
+          - --all-targets --all-features
+          # Generic clippy checks for no features (catches some missing `no_std`-only lints)
+          - --all-targets
+          # Clippy lints specifically for all runtime code, excluding all test and binary crates
+          - --target wasm32-unknown-unknown --no-default-features --workspace --exclude kilt-parachain --exclude standalone-node --exclude xcm-integration-tests --exclude 'dip-provider*' --exclude 'dip-consumer*'
       fail-fast: false
 
     steps:
@@ -63,11 +67,11 @@ jobs:
             ${{ env.CARGO_HOME }}/registry/index/
             ${{ env.CARGO_HOME }}/registry/cache/
             ${{ env.CARGO_HOME }}/git/db/
-          key: ${{ github.job }}-${{ github.ref }}-${{ matrix.features }}-${{ hashFiles('**/Cargo.lock') }}
+          key: ${{ github.job }}-${{ github.ref }}-${{ matrix.cargo-flags }}-${{ hashFiles('**/Cargo.lock') }}
           save-always: true
 
       - name: Run `cargo clippy`
-        run: cargo clippy --all-targets --locked ${{ matrix.features }}
+        run: cargo clippy --locked ${{ matrix.cargo-flags }}
 
   cargo-fmt:
     name: Check formatting

.gitlab-ci.yml

@@ -20,6 +20,7 @@ build-production-wasm:
     - export PARACHAIN_PALLET_ID=0x50
     - export AUTHORIZE_UPGRADE_PREFIX=0x02
     - export AUTHORIZE_UPGRADE_CHECK_VERSION=true
+    - export VERBOSE=true
     - cp -r * /build
     - /srtool/build build
     - subwasm meta --format=json+scale /out/${RUNTIME}_runtime.compact.wasm > /out/${RUNTIME}-metadata.json

.maintain/runtime-weight-template.hbs

@@ -13,8 +13,8 @@
 {{/each}}
 
 #![cfg_attr(rustfmt, rustfmt_skip)]
-#![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::as_conversions)]
 
 use frame_support::{traits::Get, weights::Weight};
 use sp_std::marker::PhantomData;

.maintain/weight-template.hbs

@@ -14,8 +14,8 @@
 {{/each}}
 
 #![cfg_attr(rustfmt, rustfmt_skip)]
-#![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::as_conversions)]
 
 use frame_support::{traits::Get, weights::{Weight, constants::RocksDbWeight}};
 use sp_std::marker::PhantomData;

crates/assets/src/asset.rs

@@ -44,16 +44,19 @@ pub mod v1 {
 	pub const MINIMUM_ASSET_NAMESPACE_LENGTH: usize = 3;
 	/// The maximum length of a valid asset ID namespace.
 	pub const MAXIMUM_NAMESPACE_LENGTH: usize = 8;
+	#[allow(clippy::as_conversions)]
 	const MAXIMUM_ASSET_NAMESPACE_LENGTH_U32: u32 = MAXIMUM_NAMESPACE_LENGTH as u32;
 	/// The minimum length of a valid asset ID reference.
 	pub const MINIMUM_ASSET_REFERENCE_LENGTH: usize = 1;
 	/// The maximum length of a valid asset ID reference.
 	pub const MAXIMUM_ASSET_REFERENCE_LENGTH: usize = 128;
+	#[allow(clippy::as_conversions)]
 	const MAXIMUM_ASSET_REFERENCE_LENGTH_U32: u32 = MAXIMUM_ASSET_REFERENCE_LENGTH as u32;
 	/// The minimum length of a valid asset ID identifier.
 	pub const MINIMUM_ASSET_IDENTIFIER_LENGTH: usize = 1;
 	/// The maximum length of a valid asset ID reference.
 	pub const MAXIMUM_ASSET_IDENTIFIER_LENGTH: usize = 78;
+	#[allow(clippy::as_conversions)]
 	const MAXIMUM_ASSET_IDENTIFIER_LENGTH_U32: u32 = MAXIMUM_ASSET_IDENTIFIER_LENGTH as u32;
 
 	/// Separator between asset namespace and asset reference.
@@ -168,6 +171,7 @@ pub mod v1 {
 	}
 
 	impl Display for AssetId {
+		#[allow(clippy::expect_used)]
 		fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 			match self {
 				Self::Slip44(reference) => {
@@ -335,6 +339,7 @@ pub mod v1 {
 			// TODO: This could be enforced at compilation time once constraints on generics
 			// will be available.
 			// https://rust-lang.github.io/rfcs/2000-const-generics.html
+			#[allow(clippy::expect_used)]
 			if value
 				<= U256::from_str_radix("9999999999999999999999999999999999999999999999999999999999999999", 10)
 					.expect("Casting the maximum value for a Slip44 reference into a U256 should never fail.")
@@ -480,6 +485,7 @@ pub mod v1 {
 	}
 
 	impl Display for EvmSmartContractNonFungibleIdentifier {
+		#[allow(clippy::expect_used)]
 		fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 			// We checked when the type is created that all characters are valid digits.
 			write!(
@@ -578,6 +584,7 @@ pub mod v1 {
 	}
 
 	impl Display for GenericAssetNamespace {
+		#[allow(clippy::expect_used)]
 		fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 			// We checked when the type is created that all characters are valid UTF8
 			// (actually ASCII) characters.
@@ -627,6 +634,7 @@ pub mod v1 {
 	}
 
 	impl Display for GenericAssetReference {
+		#[allow(clippy::expect_used)]
 		fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 			// We checked when the type is created that all characters are valid UTF8
 			// (actually ASCII) characters.
@@ -676,6 +684,7 @@ pub mod v1 {
 	}
 
 	impl Display for GenericAssetIdentifier {
+		#[allow(clippy::expect_used)]
 		fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 			// We checked when the type is created that all characters are valid UTF8
 			// (actually ASCII) characters.

crates/assets/src/chain.rs

@@ -45,11 +45,13 @@ mod v1 {
 	pub const MINIMUM_CHAIN_NAMESPACE_LENGTH: usize = 3;
 	/// The maximum length of a valid chain ID namespace.
 	pub const MAXIMUM_CHAIN_NAMESPACE_LENGTH: usize = 8;
+	#[allow(clippy::as_conversions)]
 	const MAXIMUM_CHAIN_NAMESPACE_LENGTH_U32: u32 = MAXIMUM_CHAIN_NAMESPACE_LENGTH as u32;
 	/// The minimum length of a valid chain ID reference.
 	pub const MINIMUM_CHAIN_REFERENCE_LENGTH: usize = 1;
 	/// The maximum length of a valid chain ID reference.
 	pub const MAXIMUM_CHAIN_REFERENCE_LENGTH: usize = 32;
+	#[allow(clippy::as_conversions)]
 	const MAXIMUM_CHAIN_REFERENCE_LENGTH_U32: u32 = MAXIMUM_CHAIN_REFERENCE_LENGTH as u32;
 
 	/// Separator between chain namespace and chain reference.
@@ -192,6 +194,7 @@ mod v1 {
 	}
 
 	impl Display for ChainId {
+		#[allow(clippy::expect_used)]
 		fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 			match self {
 				Self::Bip122(reference) => {
@@ -438,6 +441,7 @@ mod v1 {
 
 	impl GenesisBase58Hash32Reference {
 		/// The CAIP-2 reference for the Solana mainnet.
+		#[allow(clippy::expect_used)]
 		pub fn solana_mainnet() -> Self {
 			// Base58 decoding of Solana genesis hash 4sGjMW1sUnHzSxGspuhpqLDx6wiyjNtZ
 			Self(
@@ -565,6 +569,7 @@ mod v1 {
 	}
 
 	impl Display for GenericChainNamespace {
+		#[allow(clippy::expect_used)]
 		fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 			// We checked when the type is created that all characters are valid UTF8
 			// (actually ASCII) characters.
@@ -614,6 +619,7 @@ mod v1 {
 	}
 
 	impl Display for GenericChainReference {
+		#[allow(clippy::expect_used)]
 		fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 			// We checked when the type is created that all characters are valid UTF8
 			// (actually ASCII) characters.

crates/assets/src/v1.rs

@@ -146,6 +146,7 @@ impl AssetDid {
 }
 
 impl Display for AssetDid {
+	#[allow(clippy::expect_used)]
 	fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 		write!(
 			f,

crates/kilt-dip-primitives/src/merkle_proofs/v0/provider_state/mod.rs

@@ -187,6 +187,7 @@ impl<
 				if input.len() < 2 {
 					return None;
 				}
+				#[allow(clippy::indexing_slicing)]
 				let mut trimmed_input = &input[2..];
 				ProviderHeader::decode(&mut trimmed_input).ok()
 			},

crates/kilt-dip-primitives/src/verifier/parachain/error.rs

@@ -32,6 +32,8 @@ impl<DidOriginError> From<DipParachainStateProofVerifierError<DidOriginError>> f
 where
 	DidOriginError: Into<u8>,
 {
+	#[allow(clippy::as_conversions)]
+	#[allow(clippy::arithmetic_side_effects)]
 	fn from(value: DipParachainStateProofVerifierError<DidOriginError>) -> Self {
 		match value {
 			// DO NOT USE 0