ci: Fail on cargo check warnings (#963)

Makes sure we are signaling `cargo check` lints, fixes some "confusing
lifetime" ones, and deletes an unused private struct.

drive-by: Re-update `uv.lock` to `revision 2`

Author: aborgna-q

.github/workflows/ci.yml

@@ -71,6 +71,9 @@ jobs:
     needs: [changes]
     if: ${{ needs.changes.outputs.rust == 'true' }}
     runs-on: ubuntu-latest
+    env:
+      # Fail on rust compiler warnings.
+      RUSTFLAGS: -D warnings
     steps:
       - uses: actions/checkout@v4
       - uses: mozilla-actions/sccache-action@v0.0.9

.pre-commit-config.yaml

@@ -65,7 +65,7 @@ repos:
       - id: cargo-check
         name: cargo check
         description: Check rust code with `cargo check`.
-        entry: uv run -- cargo check --all --all-features --workspace
+        entry: env RUSTFLAGS="-Dwarnings" uv run -- cargo check --all --all-features --workspace
         language: system
         files: \.rs$
         pass_filenames: false

tket2-hseries/src/llvm/futures.rs

@@ -58,7 +58,7 @@ impl CodegenExtension for FuturesCodegenExtension {
 }
 
 /// The LLVM type representing a future handle.
-pub fn future_type(context: &Context) -> BasicTypeEnum {
+pub fn future_type(context: &Context) -> BasicTypeEnum<'_> {
     // The runtime represent a future handle as an i64
     context.i64_type().into()
 }

tket2-hseries/src/llvm/random.rs

@@ -34,7 +34,7 @@ impl CodegenExtension for RandomCodegenExtension {
     }
 }
 
-fn rng_context_type(context: &Context) -> BasicTypeEnum {
+fn rng_context_type(context: &Context) -> BasicTypeEnum<'_> {
     context.struct_type(&[], false).into()
 }
 

tket2-py/src/circuit/tk2circuit.rs

@@ -236,7 +236,7 @@ impl Tk2Circuit {
         Ok(self.clone())
     }
 
-    fn node_op(&self, node: PyNode) -> PyResult<Cow<[u8]>> {
+    fn node_op(&self, node: PyNode) -> PyResult<Cow<'_, [u8]>> {
         let custom: ExtensionOp = self
             .circ
             .hugr()

tket2/src/circuit.rs

@@ -320,7 +320,7 @@ impl<T: HugrView<Node = Node>> Circuit<T> {
     ///
     ///   [`Tk2Op`]: crate::Tk2Op
     #[inline]
-    pub fn operations(&self) -> impl Iterator<Item = Command<T>> + '_
+    pub fn operations(&self) -> impl Iterator<Item = Command<'_, T>> + '_
     where
         Self: Sized,
     {

tket2/src/ops.rs

@@ -17,7 +17,7 @@ use hugr::{
     types::Signature,
 };
 
-use derive_more::{Display, Error};
+use derive_more::Display;
 use serde::{Deserialize, Serialize};
 use smol_str::ToSmolStr;
 use strum::{EnumIter, EnumString, IntoStaticStr};
@@ -97,13 +97,6 @@ pub enum Pauli {
     Z,
 }
 
-#[derive(Display, Debug, Error, PartialEq, Clone)]
-#[display("{} is not a Tk2Op.", op)]
-pub struct NotTk2Op {
-    /// The offending operation.
-    pub op: OpType,
-}
-
 impl Pauli {
     /// Check if this pauli commutes with another.
     pub fn commutes_with(&self, other: Self) -> bool {