Struct FormatArgs 

pub struct FormatArgs<'tcx> {
    pub this: String,
    pub trait_sugared: TraitRefPrintSugared<'tcx>,
    pub item_context: &'static str,
    pub generic_args: Vec<(Symbol, String)>,
}

Arguments to fill a FormatString with.

For example, given a

#[rustc_on_unimplemented(
    on(all(from_desugaring = "QuestionMark"),
        message = "the `?` operator can only be used in {ItemContext} \
                    that returns `Result` or `Option` \
                    (or another type that implements `{FromResidual}`)",
        label = "cannot use the `?` operator in {ItemContext} that returns `{Self}`",
        parent_label = "this function should return `Result` or `Option` to accept `?`"
    ),
)]
pub trait FromResidual<R = <Self as Try>::Residual> {
   ...
}

async fn an_async_function() -> u32 {
    let x: Option<u32> = None;
    x?; //~ ERROR the `?` operator
    22
}

it will look like this:

FormatArgs {
    this: "FromResidual",
    trait_sugared: "FromResidual<Option<Infallible>>",
    item_context: "an async function",
    generic_args: [("Self", "u32"), ("R", "Option<Infallible>")],
}

Fields

this: String

trait_sugared: TraitRefPrintSugared<'tcx>

item_context: &'static str

generic_args: Vec<(Symbol, String)>

Trait Implementations

impl<'tcx> Debug for FormatArgs<'tcx>

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

Formats the value using the given formatter.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 80 bytes