Enum rustc_builtin_macros::deriving::generic::SubstructureFields

pub(crate) enum SubstructureFields<'a> {
    Struct(&'a VariantData, Vec<FieldInfo>),
    AllFieldlessEnum(&'a EnumDef),
    EnumMatching(usize, &'a Variant, Vec<FieldInfo>),
    EnumDiscr(FieldInfo, Option<P<Expr>>),
    StaticStruct(&'a VariantData, StaticFields),
    StaticEnum(&'a EnumDef, Vec<(Ident, Span, StaticFields)>),
}

A summary of the possible sets of fields.

Variants

Struct(&'a VariantData, Vec<FieldInfo>)

A non-static method where Self is a struct.

AllFieldlessEnum(&'a EnumDef)

A non-static method handling the entire enum at once (after it has been determined that none of the enum variants has any fields).

EnumMatching(usize, &'a Variant, Vec<FieldInfo>)

Matching variants of the enum: variant index, ast::Variant, fields: the field name is only non-None in the case of a struct variant.

EnumDiscr(FieldInfo, Option<P<Expr>>)

The discriminant of an enum. The first field is a FieldInfo for the discriminants, as if they were fields. The second field is the expression to combine the discriminant expression with; it will be None if no match is necessary.

StaticStruct(&'a VariantData, StaticFields)

A static method where Self is a struct.

StaticEnum(&'a EnumDef, Vec<(Ident, Span, StaticFields)>)

A static method where Self is an enum.

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: 64 bytes

Size for each variant:

• Struct: 40 bytes
• AllFieldlessEnum: 16 bytes
• EnumMatching: 48 bytes
• EnumDiscr: 64 bytes
• StaticStruct: 48 bytes
• StaticEnum: 40 bytes