fix(tvix/eval): address current clippy lints

Note that I've allowed `needless_lifetimes` for the attribute set
iterator, as I find the type easier to understand with these
annotations present.

Change-Id: I33abb17837ee4813076cdb9a87f54bac4a37044e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6373
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

tvix/eval/src/compiler/scope.rs

@@ -71,7 +71,7 @@ pub enum LocalPosition {
 
 /// Represents the different ways in which upvalues can be captured in
 /// closures or thunks.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum Upvalue {
     /// This upvalue captures a local from the stack.
     Local(LocalIdx),
@@ -95,7 +95,7 @@ pub enum Upvalue {
 /// is subtly different from its `StackIdx` (which excludes
 /// uninitialised values in between).
 #[repr(transparent)]
-#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd)]
 pub struct LocalIdx(usize);
 
 /// Represents a scope known during compilation, which can be resolved

tvix/eval/src/opcode.rs

@@ -13,12 +13,12 @@ pub struct CodeIdx(pub usize);
 
 /// Index of a value in the runtime stack.
 #[repr(transparent)]
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct StackIdx(pub usize);
 
 /// Index of an upvalue within a closure's upvalue list.
 #[repr(transparent)]
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct UpvalueIdx(pub usize);
 
 /// Offset by which an instruction pointer should change in a jump.

tvix/eval/src/value/attrs.rs

@@ -215,6 +215,7 @@ impl NixAttrs {
         self.0.contains(key)
     }
 
+    #[allow(clippy::needless_lifetimes)]
     pub fn iter<'a>(&'a self) -> Iter<KeyValue<'a>> {
         Iter(match &self.0 {
             AttrsRep::Map(map) => KeyValue::Map(map.iter()),

tvix/eval/src/vm.rs

@@ -527,7 +527,6 @@ impl VM {
     fn resolve_dynamic_upvalue(&mut self, ident_idx: ConstantIdx) -> EvalResult<Value> {
         let chunk = self.chunk();
         let ident = chunk.constant(ident_idx).as_str()?.to_string();
-        drop(chunk); // some lifetime trickery due to cell::Ref
 
         // Peek at the current instruction (note: IP has already
         // advanced!) to see if it is actually data indicating a