Enum ItemError 

pub enum ItemError {
    UnsupportedReceiver,
    UnsupportedParamPattern {
        pattern: String,
    },
    ParamType {
        param: Ident,
        source: UnsupportedType,
    },
    ReturnType {
        source: UnsupportedType,
    },
    FieldType {
        field: Ident,
        source: UnsupportedType,
    },
    VariantFieldType {
        variant: Ident,
        field: String,
        source: UnsupportedType,
    },
    ConstType {
        source: UnsupportedType,
    },
    UnsupportedAsync,
    UnsupportedVariadic,
    UnsupportedGenericParam {
        param: String,
        kind: &'static str,
    },
    UnresolvedType {
        name: String,
    },
    UnsupportedItemKind {
        kind: &'static str,
    },
}

Why one item could not be expressed in the language.

Carried by Element::Unsupported rather than raised at parse time: see the module docs on where acceptance is enforced.

Variants

UnsupportedReceiver

A self receiver. #[prebindgen] captures free functions only.

UnsupportedParamPattern

A parameter pattern that is not a plain name — (a, b): (u8, u8).

Fields

pattern: String

ParamType

A parameter’s type is not in the language.

Fields

param: Ident

source: UnsupportedType

ReturnType

A return type is not in the language.

Fields

source: UnsupportedType

FieldType

A named struct field’s type is not in the language.

Fields

field: Ident

source: UnsupportedType

VariantFieldType

A variant payload’s type is not in the language.

Fields

variant: Ident

field: String

The field’s name, or its position for a tuple variant.

source: UnsupportedType

ConstType

A const’s type is not in the language.

Fields

source: UnsupportedType

UnsupportedAsync

An async fn.

The most dangerous shape to accept quietly: Function has a direct return, so an async fn ping() lowers as one returning (), and a generated wrapper calls it, drops the future and exports a function whose body never runs.

UnsupportedVariadic

A C-variadic tail — fn f(a: u8, ...).

Function holds ordinary parameters only, so the tail would simply be dropped from the signature.

UnsupportedGenericParam

A type or const generic parameter on the item.

The elements have no generic binder, so a T in a field or parameter would lower as TypeKind::Named — an ordinary nominal reference into the flat namespace, indistinguishable from a real item called T. That loses the scoping every downstream resolver needs, and no destination language can express an uninstantiated parameter anyway.

A lifetime parameter is not this: lifetimes are spelling and already travel in the syntax.

Fields

param: String

kind: &'static str

a type parameter / a const generic parameter.

UnresolvedType

The item names a type the flat API does not declare.

The flat API is closed over its own names: a handle enters it through #[prebindgen] pub type X = .., so a name with no declaration is either a missing marker or a typo. Reporting it here replaces discovering it much later as an unresolved converter, from whichever adapter looked first.

Fields

name: String

UnsupportedItemKind

A whole item kind the language does not model — a union, a type alias.

The proc-macro refuses to mark a use, mod, impl or macro_rules! at all, so only the kinds it accepts can reach here.

Fields

kind: &'static str

Trait Implementations

impl Clone for ItemError

fn clone(&self) -> ItemError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ItemError

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

Formats the value using the given formatter.

impl Display for ItemError

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

Formats the value using the given formatter.

impl Error for ItemError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.