Error with Deserialize trait bound with the serde crate

[brunbjerg]

I tried this code:

#[derive(Deserialize, Debug)]
pub struct WeightParams {
    order_type_weights: HashMap<String, u32>,
    status_weights: HashMap<String, u32>,
    vis_priority_map: HashMap<String, u32>,
    wdf_priority_map: HashMap<String, u32>,
    wgn_priority_map: HashMap<String, u32>,
    wpm_priority_map: HashMap<String, u32>,
}

impl WeightParams {
    pub fn read_config() -> Result<Self, Box<dyn std::error::Error>> {
        let default_path = "scheduling_system/parameters/work_order_weight_parameters.json";
        let config_path = env::var("CONFIG_PATH").unwrap_or_else(|_| default_path.to_string());
        let config_contents = fs::read_to_string(config_path).expect("Could not read config file");

        let config: WeightParams = serde_json::from_str(&config_contents)?;

        Ok(config)
    }
}

I expected to see this happen: The code compiling correctly, and initializing the configuration struct WeightParams from the JSON string.

Instead, this happened: It says that the trait bound (Deserialize) is not satisfied when it clearly.

Meta

rustc --version --verbose:

rustc 1.77.2 (25ef9e3d8 2024-04-09)
binary: rustc
commit-hash: 25ef9e3d85d934b27d9dada2f9dd52b1dc63bb04
commit-date: 2024-04-09
host: x86_64-unknown-linux-gnu
release: 1.77.2
LLVM version: 17.0.6

Backtrace

error[E0277]: the trait bound `WeightParams: serde::de::Deserialize` is not satisfied
    --> shared_messages/src/models/work_order/mod.rs:222:36
     |
222  | ...Params = serde_json::from_str(&config_contents)?;
     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `serde::de::Deserialize` is not implemented for `WeightParams`
     |
     = help: the following other types implement trait `serde::de::Deserialize`:
               bool
               char
               isize
               i8
               i16
               i32
               i64
               usize
             and 95 others
note: required by a bound in `serde_json::from_str`
    --> /home/scipo/.cargo/registry/src/index.crates.io-6f17d22bba15001f/serde_json-0.9.10/src/de.rs:1088:14
     |
1087 | pub fn from_str<T>(s: &str) -> Result<T>
     |        -------- required by a bound in this function
1088 |     where T: de::Deserialize,
     |              ^^^^^^^^^^^^^^^ required by this bound in `from_str`

[ChayimFriedman2]

Can't reproduce.