Invalid type with serde(flatten) and u32

[nanocryk]

with dotenv = "0.15.0"

#[derive(Deserialize)]
pub struct Config {
    pub var: u32
}

works, but

#[derive(Deserialize)]
pub struct Config {
    #[serde(flatten)]
    pub sub: Sub,
}

#[derive(Deserialize)]
pub struct Sub {
    pub var: u32
}

gives an error at runtime :

Error: Custom("invalid type: string \"0\", expected u32")

[ZoeyR]

I'm confused, are you saying that merely having dotenv as a dependency is breaking serde?

[nanocryk]

No, I deserialize my .env file with dotenv::dotenv()?.
With a flat structure it works, but using [serde(flatten)] it no longer works.

EDIT: Oops, I though dotenv was responsible for der variables into a struct while it's the envy crate. Sorry.

softprops/envy#26