Trait Context 

pub trait Context: Sealed {
    // Required methods
    fn module<D>(self, name: D) -> Self
       where D: Display,
             Self: Sized;
    fn with_module<D>(self, f: impl FnOnce() -> D) -> Self
       where D: Display;
    fn trace(self, trace: Trace) -> Self;
    fn with_trace(self, f: impl FnOnce() -> Trace) -> Self;
    fn value<D>(self, name: D) -> Self
       where D: Display,
             Self: Sized;
    fn with_value<D>(self, f: impl FnOnce() -> D) -> Self
       where D: Display,
             Self: Sized;
}

Extension trait for Result.

Adds methods for adding context to an Error.

This trait is sealed and cannot be implemented for any other types.

Required Methods

fn module<D>(self, name: D) -> Self

where D: Display, Self: Sized,

Add the name of this module to the context of the error.

This method adds context to the Error so that it knows in which module the error occurred. It is perfectly fine to never use it, as long as you don’t mind cryptic errors.

Modules should be added in the following order, from the module where the error occured and then its parent module up until the root module.

fn with_module<D>(self, f: impl FnOnce() -> D) -> Self

where D: Display,

The same as Context::module but lazily-evaluated.

fn trace(self, trace: Trace) -> Self

Set the trace of the error.

This method overwrites the module trace completely with trace.

fn with_trace(self, f: impl FnOnce() -> Trace) -> Self

Set the trace of the error.

The same as Context::trace but lazily-evaluated.

fn value<D>(self, name: D) -> Self

where D: Display, Self: Sized,

Add the name of the value to the context of the error.

This method adds context to the Error so that it knows in which value the error occurred. It is perfectly fine to never use it, as long as you don’t mind cryptic errors.

fn with_value<D>(self, f: impl FnOnce() -> D) -> Self

where D: Display, Self: Sized,

The same as Context::value but lazily-evaluated.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<T> Context for Result<T, Error>

fn module<D>(self, name: D) -> Self

where D: Display, Self: Sized,

fn with_module<D>(self, f: impl FnOnce() -> D) -> Self

where D: Display,

fn trace(self, trace: Trace) -> Self

fn with_trace(self, f: impl FnOnce() -> Trace) -> Self

fn value<D>(self, name: D) -> Self

where D: Display, Self: Sized,

fn with_value<D>(self, f: impl FnOnce() -> D) -> Self

where D: Display, Self: Sized,

Implementors