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deserialize_individually macro fails clippy due to unnecessary mut

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Assessment

Difficulty
1/5
Estimated time
Under an hour
Newbie friendliness
45/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Stale
Tech stack
rust
Domain
tooling

Research direction

Open src/arena/saveload.rs and inspect the deserialize_individually macro, especially the entities argument passed to DeserializeComponents::deserialize. Run Clippy to confirm the unnecessary mutable-reference warning, then verify that the warning is gone while deserialization still works.

Written by the indexing model from the issue text.

Description

Here https://bfnightly.bracketproductions.com/rustbook/chapter_11.html#actually-loading-the-game

This code:


macro_rules! deserialize_individually {
    ($ecs:expr, $de:expr, $data:expr, $( $type:ty),*) => {
        $(
        DeserializeComponents::<NoError, _>::deserialize(
            &mut ( &mut $ecs.write_storage::<$type>(), ),
            &mut $data.0, // entities

can be


macro_rules! deserialize_individually {
    ($ecs:expr, $de:expr, $data:expr, $( $type:ty),*) => {
        $(
        DeserializeComponents::<NoError, _>::deserialize(
            &mut ( &mut $ecs.write_storage::<$type>(), ),
            &$data.0, // entities

to prevent this clippy warning:

warning: The function/method `DeserializeComponents<NoError, _>::deserialize` doesn't need a mutable reference
   --> src/arena/saveload.rs:35:13
    |
35  |               &mut $data.0, // entities
    |               ^^^^^^^^^^^^
...
115 | /         deserialize_individually!(
116 | |             ecs,
117 | |             de,
118 | |             d,
...   |
135 | |             SerializationHelper
136 | |         );
    | |__________- in this macro invocation
    |
    = note: `#[warn(clippy::unnecessary_mut_passed)]` on by default
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed
    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

warning: The function/method `DeserializeComponents<NoError, _>::deserialize` doesn't need a mutable reference
   --> src/arena/saveload.rs:35:13
    |
35  |               &mut $data.0, // entities
    |               ^^^^^^^^^^^^
...
115 | /         deserialize_individually!(
116 | |             ecs,
117 | |             de,
118 | |             d,
...   |
135 | |             SerializationHelper
136 | |         );
    | |__________- in this macro invocation
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed
    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
Dominant language
Rust
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