rust/compiler/rustc_hir/src/def.rs

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use crate::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
use crate::hir;
use rustc_ast as ast;
use rustc_ast::NodeId;
use rustc_macros::HashStable_Generic;
use rustc_span::hygiene::MacroKind;
use std::array::IntoIter;
use std::fmt::Debug;
/// Encodes if a `DefKind::Ctor` is the constructor of an enum variant or a struct.
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum CtorOf {
/// This `DefKind::Ctor` is a synthesized constructor of a tuple or unit struct.
Struct,
/// This `DefKind::Ctor` is a synthesized constructor of a tuple or unit variant.
Variant,
}
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum CtorKind {
/// Constructor function automatically created by a tuple struct/variant.
Fn,
/// Constructor constant automatically created by a unit struct/variant.
Const,
/// Unusable name in value namespace created by a struct variant.
Fictive,
}
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum NonMacroAttrKind {
/// Single-segment attribute defined by the language (`#[inline]`)
Builtin,
/// Multi-segment custom attribute living in a "tool module" (`#[rustfmt::skip]`).
Tool,
/// Single-segment custom attribute registered by a derive macro (`#[serde(default)]`).
DeriveHelper,
/// Single-segment custom attribute registered by a derive macro
/// but used before that derive macro was expanded (deprecated).
DeriveHelperCompat,
/// Single-segment custom attribute registered with `#[register_attr]`.
Registered,
}
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum DefKind {
// Type namespace
Mod,
/// Refers to the struct itself, `DefKind::Ctor` refers to its constructor if it exists.
Struct,
Union,
Enum,
/// Refers to the variant itself, `DefKind::Ctor` refers to its constructor if it exists.
Variant,
Trait,
/// `type Foo = Bar;`
TyAlias,
ForeignTy,
TraitAlias,
AssocTy,
TyParam,
// Value namespace
Fn,
Const,
ConstParam,
Static,
/// Refers to the struct or enum variant's constructor.
Ctor(CtorOf, CtorKind),
AssocFn,
AssocConst,
// Macro namespace
Macro(MacroKind),
// Not namespaced (or they are, but we don't treat them so)
ExternCrate,
Use,
ForeignMod,
AnonConst,
OpaqueTy,
Field,
LifetimeParam,
GlobalAsm,
Impl,
Closure,
Generator,
}
impl DefKind {
pub fn descr(self, def_id: DefId) -> &'static str {
match self {
DefKind::Fn => "function",
DefKind::Mod if def_id.index == CRATE_DEF_INDEX && def_id.krate != LOCAL_CRATE => {
"crate"
}
DefKind::Mod => "module",
DefKind::Static => "static",
DefKind::Enum => "enum",
DefKind::Variant => "variant",
DefKind::Ctor(CtorOf::Variant, CtorKind::Fn) => "tuple variant",
DefKind::Ctor(CtorOf::Variant, CtorKind::Const) => "unit variant",
DefKind::Ctor(CtorOf::Variant, CtorKind::Fictive) => "struct variant",
DefKind::Struct => "struct",
DefKind::Ctor(CtorOf::Struct, CtorKind::Fn) => "tuple struct",
DefKind::Ctor(CtorOf::Struct, CtorKind::Const) => "unit struct",
DefKind::Ctor(CtorOf::Struct, CtorKind::Fictive) => {
panic!("impossible struct constructor")
}
DefKind::OpaqueTy => "opaque type",
DefKind::TyAlias => "type alias",
DefKind::TraitAlias => "trait alias",
DefKind::AssocTy => "associated type",
DefKind::Union => "union",
DefKind::Trait => "trait",
DefKind::ForeignTy => "foreign type",
DefKind::AssocFn => "associated function",
DefKind::Const => "constant",
DefKind::AssocConst => "associated constant",
DefKind::TyParam => "type parameter",
DefKind::ConstParam => "const parameter",
DefKind::Macro(macro_kind) => macro_kind.descr(),
DefKind::LifetimeParam => "lifetime parameter",
DefKind::Use => "import",
DefKind::ForeignMod => "foreign module",
DefKind::AnonConst => "constant expression",
DefKind::Field => "field",
DefKind::Impl => "implementation",
DefKind::Closure => "closure",
DefKind::Generator => "generator",
DefKind::ExternCrate => "extern crate",
DefKind::GlobalAsm => "global assembly block",
}
}
/// Gets an English article for the definition.
pub fn article(&self) -> &'static str {
match *self {
DefKind::AssocTy
| DefKind::AssocConst
| DefKind::AssocFn
| DefKind::Enum
| DefKind::OpaqueTy
| DefKind::Impl
| DefKind::Use
| DefKind::ExternCrate => "an",
DefKind::Macro(macro_kind) => macro_kind.article(),
_ => "a",
}
}
pub fn ns(&self) -> Option<Namespace> {
match self {
DefKind::Mod
| DefKind::Struct
| DefKind::Union
| DefKind::Enum
| DefKind::Variant
| DefKind::Trait
| DefKind::OpaqueTy
| DefKind::TyAlias
| DefKind::ForeignTy
| DefKind::TraitAlias
| DefKind::AssocTy
| DefKind::TyParam => Some(Namespace::TypeNS),
DefKind::Fn
| DefKind::Const
| DefKind::ConstParam
| DefKind::Static
| DefKind::Ctor(..)
| DefKind::AssocFn
| DefKind::AssocConst => Some(Namespace::ValueNS),
DefKind::Macro(..) => Some(Namespace::MacroNS),
// Not namespaced.
DefKind::AnonConst
| DefKind::Field
| DefKind::LifetimeParam
| DefKind::ExternCrate
| DefKind::Closure
| DefKind::Generator
| DefKind::Use
| DefKind::ForeignMod
| DefKind::GlobalAsm
| DefKind::Impl => None,
}
}
}
/// The resolution of a path or export.
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum Res<Id = hir::HirId> {
Def(DefKind, DefId),
// Type namespace
PrimTy(hir::PrimTy),
/// `Self`, with both an optional trait and impl `DefId`.
///
/// HACK(min_const_generics): impl self types also have an optional requirement to not mention
/// any generic parameters to allow the following with `min_const_generics`:
/// ```rust
/// impl Foo { fn test() -> [u8; std::mem::size_of::<Self>()] {} }
/// ```
/// We do however allow `Self` in repeat expression even if it is generic to not break code
/// which already works on stable while causing the `const_evaluatable_unchecked` future compat lint.
///
/// FIXME(lazy_normalization_consts): Remove this bodge once that feature is stable.
SelfTy(Option<DefId> /* trait */, Option<(DefId, bool)> /* impl */),
ToolMod, // e.g., `rustfmt` in `#[rustfmt::skip]`
// Value namespace
SelfCtor(DefId /* impl */), // `DefId` refers to the impl
Local(Id),
// Macro namespace
NonMacroAttr(NonMacroAttrKind), // e.g., `#[inline]` or `#[rustfmt::skip]`
// All namespaces
Err,
}
/// The result of resolving a path before lowering to HIR,
/// with "module" segments resolved and associated item
/// segments deferred to type checking.
/// `base_res` is the resolution of the resolved part of the
/// path, `unresolved_segments` is the number of unresolved
/// segments.
///
/// ```text
/// module::Type::AssocX::AssocY::MethodOrAssocType
/// ^~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/// base_res unresolved_segments = 3
///
/// <T as Trait>::AssocX::AssocY::MethodOrAssocType
/// ^~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~
/// base_res unresolved_segments = 2
/// ```
#[derive(Copy, Clone, Debug)]
pub struct PartialRes {
base_res: Res<NodeId>,
unresolved_segments: usize,
}
impl PartialRes {
#[inline]
pub fn new(base_res: Res<NodeId>) -> Self {
PartialRes { base_res, unresolved_segments: 0 }
}
#[inline]
pub fn with_unresolved_segments(base_res: Res<NodeId>, mut unresolved_segments: usize) -> Self {
if base_res == Res::Err {
unresolved_segments = 0
}
PartialRes { base_res, unresolved_segments }
}
#[inline]
pub fn base_res(&self) -> Res<NodeId> {
self.base_res
}
#[inline]
pub fn unresolved_segments(&self) -> usize {
self.unresolved_segments
}
}
/// Different kinds of symbols don't influence each other.
///
/// Therefore, they have a separate universe (namespace).
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
pub enum Namespace {
TypeNS,
ValueNS,
MacroNS,
}
impl Namespace {
pub fn descr(self) -> &'static str {
match self {
Self::TypeNS => "type",
Self::ValueNS => "value",
Self::MacroNS => "macro",
}
}
}
/// Just a helper separate structure for each namespace.
#[derive(Copy, Clone, Default, Debug)]
pub struct PerNS<T> {
pub value_ns: T,
pub type_ns: T,
pub macro_ns: T,
}
impl<T> PerNS<T> {
pub fn map<U, F: FnMut(T) -> U>(self, mut f: F) -> PerNS<U> {
PerNS { value_ns: f(self.value_ns), type_ns: f(self.type_ns), macro_ns: f(self.macro_ns) }
}
pub fn into_iter(self) -> IntoIter<T, 3> {
IntoIter::new([self.value_ns, self.type_ns, self.macro_ns])
}
pub fn iter(&self) -> IntoIter<&T, 3> {
IntoIter::new([&self.value_ns, &self.type_ns, &self.macro_ns])
}
}
impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
type Output = T;
fn index(&self, ns: Namespace) -> &T {
match ns {
Namespace::ValueNS => &self.value_ns,
Namespace::TypeNS => &self.type_ns,
Namespace::MacroNS => &self.macro_ns,
}
}
}
impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
fn index_mut(&mut self, ns: Namespace) -> &mut T {
match ns {
Namespace::ValueNS => &mut self.value_ns,
Namespace::TypeNS => &mut self.type_ns,
Namespace::MacroNS => &mut self.macro_ns,
}
}
}
impl<T> PerNS<Option<T>> {
/// Returns `true` if all the items in this collection are `None`.
pub fn is_empty(&self) -> bool {
self.type_ns.is_none() && self.value_ns.is_none() && self.macro_ns.is_none()
}
/// Returns an iterator over the items which are `Some`.
pub fn present_items(self) -> impl Iterator<Item = T> {
IntoIter::new([self.type_ns, self.value_ns, self.macro_ns]).filter_map(|it| it)
}
}
impl CtorKind {
pub fn from_ast(vdata: &ast::VariantData) -> CtorKind {
match *vdata {
ast::VariantData::Tuple(..) => CtorKind::Fn,
ast::VariantData::Unit(..) => CtorKind::Const,
ast::VariantData::Struct(..) => CtorKind::Fictive,
}
}
pub fn from_hir(vdata: &hir::VariantData<'_>) -> CtorKind {
match *vdata {
hir::VariantData::Tuple(..) => CtorKind::Fn,
hir::VariantData::Unit(..) => CtorKind::Const,
hir::VariantData::Struct(..) => CtorKind::Fictive,
}
}
}
impl NonMacroAttrKind {
pub fn descr(self) -> &'static str {
match self {
NonMacroAttrKind::Builtin => "built-in attribute",
NonMacroAttrKind::Tool => "tool attribute",
NonMacroAttrKind::DeriveHelper | NonMacroAttrKind::DeriveHelperCompat => {
"derive helper attribute"
}
NonMacroAttrKind::Registered => "explicitly registered attribute",
}
}
pub fn article(self) -> &'static str {
match self {
NonMacroAttrKind::Registered => "an",
_ => "a",
}
}
/// Users of some attributes cannot mark them as used, so they are considered always used.
pub fn is_used(self) -> bool {
match self {
NonMacroAttrKind::Tool
| NonMacroAttrKind::DeriveHelper
| NonMacroAttrKind::DeriveHelperCompat => true,
NonMacroAttrKind::Builtin | NonMacroAttrKind::Registered => false,
}
}
}
impl<Id> Res<Id> {
/// Return the `DefId` of this `Def` if it has an ID, else panic.
pub fn def_id(&self) -> DefId
where
Id: Debug,
{
self.opt_def_id()
.unwrap_or_else(|| panic!("attempted .def_id() on invalid res: {:?}", self))
}
/// Return `Some(..)` with the `DefId` of this `Res` if it has a ID, else `None`.
pub fn opt_def_id(&self) -> Option<DefId> {
match *self {
Res::Def(_, id) => Some(id),
Res::Local(..)
| Res::PrimTy(..)
| Res::SelfTy(..)
| Res::SelfCtor(..)
| Res::ToolMod
| Res::NonMacroAttr(..)
| Res::Err => None,
}
}
/// Return the `DefId` of this `Res` if it represents a module.
pub fn mod_def_id(&self) -> Option<DefId> {
match *self {
Res::Def(DefKind::Mod, id) => Some(id),
_ => None,
}
}
/// A human readable name for the res kind ("function", "module", etc.).
pub fn descr(&self) -> &'static str {
match *self {
Res::Def(kind, def_id) => kind.descr(def_id),
Res::SelfCtor(..) => "self constructor",
Res::PrimTy(..) => "builtin type",
Res::Local(..) => "local variable",
Res::SelfTy(..) => "self type",
Res::ToolMod => "tool module",
Res::NonMacroAttr(attr_kind) => attr_kind.descr(),
Res::Err => "unresolved item",
}
}
/// Gets an English article for the `Res`.
pub fn article(&self) -> &'static str {
match *self {
Res::Def(kind, _) => kind.article(),
Res::NonMacroAttr(kind) => kind.article(),
Res::Err => "an",
_ => "a",
}
}
pub fn map_id<R>(self, mut map: impl FnMut(Id) -> R) -> Res<R> {
match self {
Res::Def(kind, id) => Res::Def(kind, id),
Res::SelfCtor(id) => Res::SelfCtor(id),
Res::PrimTy(id) => Res::PrimTy(id),
Res::Local(id) => Res::Local(map(id)),
Res::SelfTy(a, b) => Res::SelfTy(a, b),
Res::ToolMod => Res::ToolMod,
Res::NonMacroAttr(attr_kind) => Res::NonMacroAttr(attr_kind),
Res::Err => Res::Err,
}
}
pub fn macro_kind(self) -> Option<MacroKind> {
match self {
Res::Def(DefKind::Macro(kind), _) => Some(kind),
Res::NonMacroAttr(..) => Some(MacroKind::Attr),
_ => None,
}
}
/// Returns `None` if this is `Res::Err`
pub fn ns(&self) -> Option<Namespace> {
match self {
Res::Def(kind, ..) => kind.ns(),
Res::PrimTy(..) | Res::SelfTy(..) | Res::ToolMod => Some(Namespace::TypeNS),
Res::SelfCtor(..) | Res::Local(..) => Some(Namespace::ValueNS),
Res::NonMacroAttr(..) => Some(Namespace::MacroNS),
Res::Err => None,
}
}
/// Always returns `true` if `self` is `Res::Err`
pub fn matches_ns(&self, ns: Namespace) -> bool {
self.ns().map_or(true, |actual_ns| actual_ns == ns)
}
/// Returns whether such a resolved path can occur in a tuple struct/variant pattern
pub fn expected_in_tuple_struct_pat(&self) -> bool {
matches!(self, Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) | Res::SelfCtor(..))
}
}