Trait rustc_middle::ty::layout::LayoutOfHelpers[−][src]

pub trait LayoutOfHelpers<'tcx>: HasDataLayout + HasTyCtxt<'tcx> + HasParamEnv<'tcx> {
    type LayoutOfResult: MaybeResult<TyAndLayout<'tcx>>;
    fn handle_layout_err(
        &self, 
        err: LayoutError<'tcx>, 
        span: Span, 
        ty: Ty<'tcx>
    ) -> <Self::LayoutOfResult as MaybeResult<TyAndLayout<'tcx, &'tcx TyS<'tcx>>>>::Error;

    fn layout_tcx_at_span(&self) -> Span { ... }
}

Expand description

Trait for contexts that want to be able to compute layouts of types. This automatically gives access to LayoutOf, through a blanket impl.

Associated Types

[src]

type LayoutOfResult: MaybeResult<TyAndLayout<'tcx>>

The TyAndLayout-wrapping type (or TyAndLayout itself), which will be returned from layout_of (see also handle_layout_err).

Required methods

[src]

fn handle_layout_err(
    &self,
    err: LayoutError<'tcx>,
    span: Span,
    ty: Ty<'tcx>
) -> <Self::LayoutOfResult as MaybeResult<TyAndLayout<'tcx, &'tcx TyS<'tcx>>>>::Error

Helper used for layout_of, to adapt tcx.layout_of(...) into a Self::LayoutOfResult (which does not need to be a Result<...>).

Most impls, which propagate LayoutErrors, should simply return err, but this hook allows e.g. codegen to return only TyAndLayout from its cx.layout_of(...), without any Result<...> around it to deal with (and any LayoutErrors are turned into fatal errors or ICEs).