Struct Label 

pub struct Label {
    pub span: Span,
    pub file: Option<FileId>,
    pub message: String,
}

A span with something to say about it.

The file is None for the ordinary case, which is a label about the file the diagnostic was filed against, and that is most of them: 23 of the 31 places this compiler builds one can only ever have a span from their own file in hand. Some is for the rest, where the thing worth pointing at is somewhere else, and until it existed those producers had to choose between drawing a caret over whatever happened to sit at those byte offsets in the wrong file and saying nothing. They all chose to say nothing, which is the right call and is still a label a reader does not get.

Fields

span: Span

file: Option<FileId>

Where span is an offset into. None means the diagnostic’s own file.

message: String

Implementations

impl Label

pub fn new(span: Span, message: impl Into<String>) -> Self

pub fn in_file(file: FileId, span: Span, message: impl Into<String>) -> Self

A label about a file other than the one the diagnostic is filed against.

pub fn file_or(&self, diagnostic: FileId) -> FileId

The file this label is about, given the diagnostic it belongs to.

Trait Implementations

impl Clone for Label

fn clone(&self) -> Label

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Label

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.