Struct TraitDecl

pub struct TraitDecl {
    pub def_id: TraitDeclId,
    pub item_meta: ItemMeta,
    pub generics: GenericParams,
    pub parent_clauses: Vector<TraitClauseId, TraitClause>,
    pub consts: Vec<TraitAssocConst>,
    pub types: Vec<Binder<TraitAssocTy>>,
    pub methods: Vec<Binder<TraitMethod>>,
    pub vtable: Option<TypeDeclRef>,
}

A trait declaration.

For instance:

trait Foo {
  type Bar;

  fn baz(...); // required method (see below)

  fn test() -> bool { true } // provided method (see below)
}

In case of a trait declaration, we don’t include the provided methods (the methods with a default implementation): they will be translated on a per-need basis. This is important for two reasons:

• this makes the trait definitions a lot smaller (the Iterator trait has one declared function and more than 70 provided functions)
• this is important for the external traits, whose provided methods often use features we don’t support yet

Remark: In Aeneas, we still translate the provided methods on an individual basis, and in such a way thay they take as input a trait instance. This means that we can use default methods but:

• implementations of required methods shoudln’t call default methods
• trait implementations shouldn’t redefine required methods The use case we have in mind is std::iter::Iterator: it declares one required method (next) that should be implemented for every iterator, and defines many helpers like all, map, etc. that shouldn’t be re-implemented. Of course, this forbids other useful use cases such as visitors implemented by means of traits.

Fields

def_id: TraitDeclId

item_meta: ItemMeta

generics: GenericParams

parent_clauses: Vector<TraitClauseId, TraitClause>

The “parent” clauses: the supertraits.

Supertraits are actually regular where clauses, but we decided to have a custom treatment.

trait Foo : Bar {
            ^^^
        supertrait, that we treat as a parent predicate
}

TODO: actually, as of today, we consider that all trait clauses of trait declarations are parent clauses.

consts: Vec<TraitAssocConst>

The associated constants declared in the trait.

types: Vec<Binder<TraitAssocTy>>

The associated types declared in the trait. The binder binds the generic parameters of the type if it is a GAT (Generic Associated Type). For a plain associated type the binder binds nothing.

methods: Vec<Binder<TraitMethod>>

The methods declared by the trait. The binder binds the generic parameters of the method.

trait Trait<T> {
  // The `Binder` for this method binds `'a` and `U`.
  fn method<'a, U>(x: &'a U);
}

vtable: Option<TypeDeclRef>

The virtual table struct for this trait, if it has one. It is guaranteed that the trait has a vtable iff it is dyn-compatible.

Implementations

impl TraitDecl

pub fn methods(&self) -> impl Iterator<Item = &Binder<TraitMethod>>

Trait Implementations

impl AstVisitable for TraitDecl

fn drive<V: VisitAst>(&self, v: &mut V) -> ControlFlow<V::Break>

Recursively visit this type with the provided visitor. This calls the visitor’s visit_$any method if it exists, otherwise visit_inner.

fn drive_mut<V: VisitAstMut>(&mut self, v: &mut V) -> ControlFlow<V::Break>

Recursively visit this type with the provided visitor. This calls the visitor’s visit_$any method if it exists, otherwise visit_inner.

fn name(&self) -> &'static str

The name of the type, used for debug logging.

fn dyn_visit<T: AstVisitable>(&self, f: impl FnMut(&T))

Visit all occurrences of that type inside self, in pre-order traversal.

fn dyn_visit_mut<T: AstVisitable>(&mut self, f: impl FnMut(&mut T))

Visit all occurrences of that type inside self, in pre-order traversal.

impl Clone for TraitDecl

fn clone(&self) -> TraitDecl

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TraitDecl

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TraitDecl

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'s, V> Drive<'s, V> for TraitDecl

where V: Visitor + Visit<'s, ItemMeta> + Visit<'s, GenericParams> + Visit<'s, Vector<TraitClauseId, TraitClause>> + Visit<'s, Vec<TraitAssocConst>> + Visit<'s, Vec<Binder<TraitAssocTy>>> + Visit<'s, Vec<Binder<TraitMethod>>> + Visit<'s, Option<TypeDeclRef>>,

fn drive_inner(&'s self, visitor: &mut V) -> ControlFlow<V::Break>

Call v.visit() on the immediate contents of self.

impl<'s, V> DriveMut<'s, V> for TraitDecl

where V: Visitor + VisitMut<'s, ItemMeta> + VisitMut<'s, GenericParams> + VisitMut<'s, Vector<TraitClauseId, TraitClause>> + VisitMut<'s, Vec<TraitAssocConst>> + VisitMut<'s, Vec<Binder<TraitAssocTy>>> + VisitMut<'s, Vec<Binder<TraitMethod>>> + VisitMut<'s, Option<TypeDeclRef>>,

fn drive_inner_mut(&'s mut self, visitor: &mut V) -> ControlFlow<V::Break>

Call v.visit() on the immediate contents of self.

impl<C: AstFormatter> FmtWithCtx<C> for TraitDecl

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

fn with_ctx<'a>(&'a self, ctx: &'a C) -> WithCtx<'a, C, Self>

Returns a struct that implements Display. This allows the following:

fn to_string_with_ctx(&self, ctx: &C) -> String

impl Serialize for TraitDecl

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.