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//! Definitions used in derived implementations of [`core::ops`] traits.
use core::fmt;
/// Error returned by the derived implementations when an arithmetic or logic
/// operation is invoked on a unit-like variant of an enum.
#[derive(Clone, Copy, Debug)]
pub struct UnitError {
operation_name: &'static str,
}
impl UnitError {
#[doc(hidden)]
#[must_use]
#[inline]
pub const fn new(operation_name: &'static str) -> Self {
Self { operation_name }
}
}
impl fmt::Display for UnitError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Cannot {}() unit variants", self.operation_name)
}
}
#[cfg(feature = "std")]
impl std::error::Error for UnitError {}
#[cfg(feature = "add")]
/// Error returned by the derived implementations when an arithmetic or logic
/// operation is invoked on mismatched enum variants.
#[derive(Clone, Copy, Debug)]
pub struct WrongVariantError {
operation_name: &'static str,
}
#[cfg(feature = "add")]
impl WrongVariantError {
#[doc(hidden)]
#[must_use]
#[inline]
pub const fn new(operation_name: &'static str) -> Self {
Self { operation_name }
}
}
#[cfg(feature = "add")]
impl fmt::Display for WrongVariantError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"Trying to {}() mismatched enum variants",
self.operation_name
)
}
}
#[cfg(all(feature = "add", feature = "std"))]
impl std::error::Error for WrongVariantError {}
#[cfg(feature = "add")]
/// Possible errors returned by the derived implementations of binary
/// arithmetic or logic operations.
#[derive(Clone, Copy, Debug)]
pub enum BinaryError {
/// Operation is attempted between mismatched enum variants.
Mismatch(WrongVariantError),
/// Operation is attempted on unit-like enum variants.
Unit(UnitError),
}
#[cfg(feature = "add")]
impl fmt::Display for BinaryError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::Mismatch(e) => write!(f, "{e}"),
Self::Unit(e) => write!(f, "{e}"),
}
}
}
#[cfg(all(feature = "add", feature = "std"))]
impl std::error::Error for BinaryError {
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
match self {
Self::Mismatch(e) => e.source(),
Self::Unit(e) => e.source(),
}
}
}