[][src]Trait serde::de::Expected

pub trait Expected {
    fn fmt(&self, formatter: &mut Formatter) -> Result;

Expected represents an explanation of what data a Visitor was expecting to receive.

This is used as an argument to the invalid_type, invalid_value, and invalid_length methods of the Error trait to build error messages. The message should be a noun or noun phrase that completes the sentence "This Visitor expects to receive ...", for example the message could be "an integer between 0 and 64". The message should not be capitalized and should not end with a period.

Within the context of a Visitor implementation, the Visitor itself (&self) is an implementation of this trait.

This code runs with edition 2018
fn visit_bool<E>(self, v: bool) -> Result<Self::Value, E>
    E: de::Error,
    Err(de::Error::invalid_type(Unexpected::Bool(v), &self))

Outside of a Visitor, &"..." can be used.

This code runs with edition 2018
return Err(de::Error::invalid_type(Unexpected::Bool(v), &"a negative integer"));

Required methods

fn fmt(&self, formatter: &mut Formatter) -> Result

Format an explanation of what data was being expected. Same signature as the Display and Debug traits.

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Trait Implementations

impl<'a> Display for dyn Expected + 'a[src]

Implementations on Foreign Types

impl<'a> Expected for &'a str[src]

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impl<'de, T> Expected for T where
    T: Visitor<'de>, 

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