Trait SpanRanged

pub trait SpanRanged {
    // Required method
    fn span_range(&self) -> Range<Span> ;

    // Provided method
    fn span_joined(&self) -> Option<Span> { ... }
}

Returns the Range<Span> from the start to the end of multi-token structures.

start and end can be the same when called on single Tokens or Span.

Due to compiler limitations, it is currently not possible to implement SpanRanged for T: ToTokens, therefor there is to_tokens_span_range().

For types that either implement SpanRanged or ToTokens (but NOT both) the span_range! macro can be used as well.

Motivation

This is superior to a normal Span (at least until Span::join works on stable), because it leads to better error messages:

Given the following expression

let a = |something: usize| something;

ErrorMessage::new(first_pipe_span, "error message") would result in something like

error: error message

let a = |something: usize| something;
        ^

While ErrorMessage::new(first_pipe_span..something_span, "error message") would improve the error message to:

error: error message

let a = |something: usize| something;
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Required Methods

fn span_range(&self) -> Range<Span>

Returns the Range<Span> fully encompasing self

Provided Methods

fn span_joined(&self) -> Option<Span>

Returns Self::span_range as a single span if possible, currently only possible on nightly. more

Implementations on Foreign Types

impl SpanRanged for Span

fn span_range(&self) -> Range<Span>

impl SpanRanged for TokenStream

fn span_range(&self) -> Range<Span>

impl SpanRanged for Span

fn span_range(&self) -> Range<Span>

impl<A: SpanRanged, B: SpanRanged> SpanRanged for (A, B)

fn span_range(&self) -> Range<Span>

impl<T: SpanRanged> SpanRanged for Option<T>

fn span_range(&self) -> Range<Span>

impl<T: SpanRanged> SpanRanged for &T

fn span_range(&self) -> Range<Span>

impl<T: SpanRanged> SpanRanged for Range<T>

fn span_range(&self) -> Range<Span>

Implementors