fix(tvix/eval): fix current clippy warnings

It's been a while since the last time, so quite a lot of stuff has
accumulated here.

Change-Id: I0762827c197b30a917ff470fd8ae8f220f6ba247
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7597
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

tvix/eval/src/value/attrs.rs

@@ -321,7 +321,6 @@ impl NixAttrs {
             }
         }
 
-        // TODO(tazjin): extend_reserve(count) (rust#72631)
         let mut attrs = NixAttrs(AttrsRep::Map(BTreeMap::new()));
 
         for _ in 0..count {

tvix/eval/src/value/function.rs

@@ -30,7 +30,7 @@ impl Formals {
         Q: ?Sized + Hash + Eq,
         NixString: std::borrow::Borrow<Q>,
     {
-        self.ellipsis || self.arguments.contains_key(&arg)
+        self.ellipsis || self.arguments.contains_key(arg)
     }
 }
 

tvix/eval/src/value/mod.rs

@@ -217,7 +217,7 @@ impl Value {
                         if let Value::Thunk(t) = f {
                             t.force(vm)?;
                             let guard = t.value();
-                            call_to_string(&*guard, vm)
+                            call_to_string(&guard, vm)
                         } else {
                             call_to_string(f, vm)
                         }
@@ -451,7 +451,7 @@ impl Value {
                 if let Some(name) = &f.lambda.name {
                     format!("the user-defined Nix function '{}'", name)
                 } else {
-                    format!("a user-defined Nix function")
+                    "a user-defined Nix function".to_string()
                 }
             }
 

tvix/eval/src/value/string.rs

@@ -172,7 +172,7 @@ fn is_valid_nix_identifier(s: &str) -> bool {
             _ => return false,
         }
     }
-    return true;
+    true
 }
 
 /// Escape a Nix string for display, as most user-visible representation

tvix/eval/src/value/thunk.rs

@@ -143,7 +143,7 @@ impl Thunk {
                 }) => vm.enter_frame(lambda, upvalues, arg_count)?,
             }
             match trampoline.continuation {
-                None => break (),
+                None => break,
                 Some(cont) => {
                     trampoline = cont(vm)?;
                     continue;
@@ -203,7 +203,7 @@ impl Thunk {
                         return Ok(Trampoline {
                             action: Some(TrampolineAction::EnterFrame {
                                 lambda,
-                                upvalues: upvalues.clone(),
+                                upvalues,
                                 arg_count: 0,
                                 light_span: light_span.clone(),
                             }),
@@ -212,10 +212,10 @@ impl Thunk {
                                     self_clone.0.replace(ThunkRepr::Evaluated(vm.pop()));
                                 assert!(matches!(should_be_blackhole, ThunkRepr::Blackhole));
                                 vm.push(Value::Thunk(self_clone));
-                                return Self::force_trampoline(vm).map_err(|kind| Error {
+                                Self::force_trampoline(vm).map_err(|kind| Error {
                                     kind,
                                     span: light_span.span(),
-                                });
+                                })
                             })),
                         });
                     }
@@ -268,7 +268,7 @@ impl Thunk {
                     panic!("Thunk::value called on an unfinalised closure");
                 }
                 */
-                return value;
+                value
             }
             ThunkRepr::Blackhole => panic!("Thunk::value called on a black-holed thunk"),
             ThunkRepr::Suspended { .. } => panic!("Thunk::value called on a suspended thunk"),