Struct rustc_builtin_macros::deriving::generic::MethodDef

pub 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

impl<'a> MethodDef<'a>

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

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

fn is_static(&self) -> bool

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>)>)

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>

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);
    }
}

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

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.

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

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