# Struct rustc_builtin_macros::deriving::generic::MethodDef

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    pub(crate) struct MethodDef<'a> {
        pub name: Symbol,
        pub generics: Bounds,
        pub explicit_self: bool,
        pub nonself_args: Vec<(Ty, Symbol)>,
        pub ret_ty: Ty,
        pub attributes: AttrVec,
        pub fieldless_variants_strategy: FieldlessVariantsStrategy,
        pub combine_substructure: RefCell<Box<dyn FnMut(&ExtCtxt<'_>, Span, &Substructure<'_>) -> BlockOrExpr + 'a>>,
    }

## Fields§

§`name: Symbol`

name of the method

§`generics: Bounds`

List of generics, e.g., `R: rand::Rng`

§`explicit_self: bool`

Is there is a `&self` argument? If not, it is a static function.

§`nonself_args: Vec<(Ty, Symbol)>`

Arguments other than the self argument.

§`ret_ty: Ty`

Returns type

§`attributes: AttrVec`§`fieldless_variants_strategy: FieldlessVariantsStrategy`§`combine_substructure: RefCell<Box<dyn FnMut(&ExtCtxt<'_>, Span, &Substructure<'_>) -> BlockOrExpr + 'a>>`

## Implementations§

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### impl<'a> MethodDef<'a>

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#### fn call_substructure_method( &self, cx: &ExtCtxt<'_>, trait_: &TraitDef<'_>, type_ident: Ident, nonselflike_args: &[P<Expr>], fields: &SubstructureFields<'_>, ) -> BlockOrExpr

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#### fn get_ret_ty( &self, cx: &ExtCtxt<'_>, trait_: &TraitDef<'_>, generics: &Generics, type_ident: Ident, ) -> P<Ty>

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#### fn is_static(&self) -> bool

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#### fn extract_arg_details( &self, cx: &ExtCtxt<'_>, trait_: &TraitDef<'_>, type_ident: Ident, generics: &Generics, ) -> (Option<ExplicitSelf>, ThinVec<P<Expr>>, Vec<P<Expr>>, Vec<(Ident, P<Ty>)>)

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#### fn create_method( &self, cx: &ExtCtxt<'_>, trait_: &TraitDef<'_>, type_ident: Ident, generics: &Generics, explicit_self: Option<ExplicitSelf>, nonself_arg_tys: Vec<(Ident, P<Ty>)>, body: BlockOrExpr, ) -> P<AssocItem>

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#### fn expand_struct_method_body<'b>( &self, cx: &ExtCtxt<'_>, trait_: &TraitDef<'b>, struct_def: &'b VariantData, type_ident: Ident, selflike_args: &[P<Expr>], nonselflike_args: &[P<Expr>], is_packed: bool, ) -> BlockOrExpr

The normal case uses field access.

    #[derive(PartialEq)]
    struct A { x: u8, y: u8 }

    // equivalent to:
    impl PartialEq for A {
        fn eq(&self, other: &A) -> bool {
            self.x == other.x && self.y == other.y
        }
    }

But if the struct is `repr(packed)`, we can’t use something like `&self.x` because that might cause an unaligned ref. So for any trait method that takes a reference, we use a local block to force a copy. This requires that the field impl `Copy`.

ⓘ

    impl PartialEq for A {
        fn eq(&self, other: &A) -> bool {
            // Desugars to `{ self.x }.eq(&{ other.y }) && ...`
            { self.x } == { other.y } && { self.y } == { other.y }
        }
    }
    impl Hash for A {
        fn hash<__H: ::core::hash::Hasher>(&self, state: &mut __H) -> () {
            ::core::hash::Hash::hash(&{ self.x }, state);
            ::core::hash::Hash::hash(&{ self.y }, state);
        }
    }

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#### fn expand_static_struct_method_body( &self, cx: &ExtCtxt<'_>, trait_: &TraitDef<'_>, struct_def: &VariantData, type_ident: Ident, nonselflike_args: &[P<Expr>], ) -> BlockOrExpr

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#### fn expand_enum_method_body<'b>( &self, cx: &ExtCtxt<'_>, trait_: &TraitDef<'b>, enum_def: &'b EnumDef, type_ident: Ident, selflike_args: ThinVec<P<Expr>>, nonselflike_args: &[P<Expr>], ) -> BlockOrExpr

    #[derive(PartialEq)]
    enum A {
        A1,
        A2(i32)
    }

is equivalent to:

    #![feature(core_intrinsics)]
    enum A {
        A1,
        A2(i32)
    }
    impl ::core::cmp::PartialEq for A {
        #[inline]
        fn eq(&self, other: &A) -> bool {
            let __self_discr = ::core::intrinsics::discriminant_value(self);
            let __arg1_discr = ::core::intrinsics::discriminant_value(other);
            __self_discr == __arg1_discr
                && match (self, other) {
                    (A::A2(__self_0), A::A2(__arg1_0)) => *__self_0 == *__arg1_0,
                    _ => true,
                }
        }
    }

Creates a discriminant check combined with a match for a tuple of all `selflike_args`, with an arm for each variant with fields, possibly an arm for each fieldless variant (if `unify_fieldless_variants` is not `Unify`), and possibly a default arm.

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#### fn expand_static_enum_method_body( &self, cx: &ExtCtxt<'_>, trait_: &TraitDef<'_>, enum_def: &EnumDef, type_ident: Ident, nonselflike_args: &[P<Expr>], ) -> BlockOrExpr

## Auto Trait Implementations§

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### impl<'a> !DynSend for MethodDef<'a>

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### impl<'a> !DynSync for MethodDef<'a>

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### impl<'a> !Freeze for MethodDef<'a>

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### impl<'a> !RefUnwindSafe for MethodDef<'a>

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### impl<'a> !Send for MethodDef<'a>

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### impl<'a> !Sync for MethodDef<'a>

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### impl<'a> Unpin for MethodDef<'a>

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### impl<'a> !UnwindSafe for MethodDef<'a>

## Blanket Implementations§

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### impl<T> Aligned for T

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#### const ALIGN: Alignment = _

Alignment of `Self`.
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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T, R> CollectAndApply<T, R> for T

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#### fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to `f(&iter.collect::<Vec<_>>())`.

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#### type Output = R

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### impl<T> Filterable for T

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#### fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T> Instrument for T

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#### fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided `Span`, returning an `Instrumented` wrapper. Read more
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#### fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current `Span`, returning an `Instrumented` wrapper. Read more
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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> IntoEither for T

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#### fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts `self` into a `Left` variant of `Either<Self, Self>` if `into_left` is `true`. Converts `self` into a `Right` variant of `Either<Self, Self>` otherwise. Read more
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#### fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts `self` into a `Left` variant of `Either<Self, Self>` if `into_left(&self)` returns `true`. Converts `self` into a `Right` variant of `Either<Self, Self>` otherwise. Read more
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### impl<T> Pointable for T

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#### const ALIGN: usize = _

The alignment of pointer.
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#### type Init = T

The type for initializers.
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#### unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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#### unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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#### unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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#### unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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### impl<T> Same for T

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#### type Output = T

Should always be `Self`
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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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### impl<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

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#### fn upcast(self, interner: I) -> U

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### impl<I, T> UpcastFrom<I, T> for T

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#### fn upcast_from(from: T, _tcx: I) -> T

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### impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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#### fn vzip(self) -> V

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### impl<T> WithSubscriber for T

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#### fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided `Subscriber` to this type, returning a `WithDispatch` wrapper. Read more
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#### fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default `Subscriber` to this type, returning a `WithDispatch` wrapper. Read more
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### impl<'a, T> Captures<'a> for T
where T: ?Sized,

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### impl<T> ErasedDestructor for T
where T: 'static,

## 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: 144 bytes