rust/src/librustc/hir/def.rs
2018-12-07 23:53:34 +00:00

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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use hir::def_id::DefId;
use util::nodemap::{NodeMap, DefIdMap};
use syntax::ast;
use syntax::ext::base::MacroKind;
use syntax_pos::Span;
use hir;
use ty;
use self::Namespace::*;
#[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
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, RustcEncodable, RustcDecodable, Hash, Debug)]
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 legacy plugin (`register_attribute`).
LegacyPluginHelper,
/// Single-segment custom attribute not registered in any way (`#[my_attr]`).
Custom,
}
#[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
pub enum Def {
// Type namespace
Mod(DefId),
Struct(DefId), // `DefId` refers to `NodeId` of the struct itself
Union(DefId),
Enum(DefId),
Variant(DefId),
Trait(DefId),
/// `existential type Foo: Bar;`
Existential(DefId),
/// `type Foo = Bar;`
TyAlias(DefId),
ForeignTy(DefId),
TraitAlias(DefId),
AssociatedTy(DefId),
/// `existential type Foo: Bar;`
AssociatedExistential(DefId),
PrimTy(hir::PrimTy),
TyParam(DefId),
SelfTy(Option<DefId> /* trait */, Option<DefId> /* impl */),
ToolMod, // e.g., `rustfmt` in `#[rustfmt::skip]`
// Value namespace
Fn(DefId),
Const(DefId),
Static(DefId, bool /* is_mutbl */),
StructCtor(DefId, CtorKind), // `DefId` refers to `NodeId` of the struct's constructor
VariantCtor(DefId, CtorKind), // `DefId` refers to the enum variant
SelfCtor(DefId /* impl */), // `DefId` refers to the impl
Method(DefId),
AssociatedConst(DefId),
Local(ast::NodeId),
Upvar(ast::NodeId, // `NodeId` of closed over local
usize, // index in the `freevars` list of the closure
ast::NodeId), // expr node that creates the closure
Label(ast::NodeId),
// Macro namespace
Macro(DefId, MacroKind),
NonMacroAttr(NonMacroAttrKind), // e.g., `#[inline]` or `#[rustfmt::skip]`
// Both namespaces
Err,
}
/// The result of resolving a path before lowering to HIR.
/// `base_def` is definition of resolved part of the
/// path, `unresolved_segments` is the number of unresolved
/// segments.
///
/// ```text
/// module::Type::AssocX::AssocY::MethodOrAssocType
/// ^~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/// base_def unresolved_segments = 3
///
/// <T as Trait>::AssocX::AssocY::MethodOrAssocType
/// ^~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~
/// base_def unresolved_segments = 2
/// ```
#[derive(Copy, Clone, Debug)]
pub struct PathResolution {
base_def: Def,
unresolved_segments: usize,
}
impl PathResolution {
pub fn new(def: Def) -> Self {
PathResolution { base_def: def, unresolved_segments: 0 }
}
pub fn with_unresolved_segments(def: Def, mut unresolved_segments: usize) -> Self {
if def == Def::Err { unresolved_segments = 0 }
PathResolution { base_def: def, unresolved_segments: unresolved_segments }
}
#[inline]
pub fn base_def(&self) -> Def {
self.base_def
}
#[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 {
TypeNS => "type",
ValueNS => "value",
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),
}
}
}
impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
type Output = T;
fn index(&self, ns: Namespace) -> &T {
match ns {
ValueNS => &self.value_ns,
TypeNS => &self.type_ns,
MacroNS => &self.macro_ns,
}
}
}
impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
fn index_mut(&mut self, ns: Namespace) -> &mut T {
match ns {
ValueNS => &mut self.value_ns,
TypeNS => &mut self.type_ns,
MacroNS => &mut self.macro_ns,
}
}
}
impl<T> PerNS<Option<T>> {
/// Returns whether 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> {
use std::iter::once;
once(self.type_ns)
.chain(once(self.value_ns))
.chain(once(self.macro_ns))
.filter_map(|it| it)
}
}
/// Definition mapping
pub type DefMap = NodeMap<PathResolution>;
/// This is the replacement export map. It maps a module to all of the exports
/// within.
pub type ExportMap = DefIdMap<Vec<Export>>;
/// Map used to track the `use` statements within a scope, matching it with all the items in every
/// namespace.
pub type ImportMap = NodeMap<PerNS<Option<PathResolution>>>;
#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
pub struct Export {
/// The name of the target.
pub ident: ast::Ident,
/// The definition of the target.
pub def: Def,
/// The span of the target definition.
pub span: Span,
/// The visibility of the export.
/// We include non-`pub` exports for hygienic macros that get used from extern crates.
pub vis: ty::Visibility,
}
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 {
fn descr(self) -> &'static str {
match self {
NonMacroAttrKind::Builtin => "built-in attribute",
NonMacroAttrKind::Tool => "tool attribute",
NonMacroAttrKind::DeriveHelper => "derive helper attribute",
NonMacroAttrKind::LegacyPluginHelper => "legacy plugin helper attribute",
NonMacroAttrKind::Custom => "custom attribute",
}
}
}
impl Def {
pub fn def_id(&self) -> DefId {
self.opt_def_id().unwrap_or_else(|| {
bug!("attempted .def_id() on invalid def: {:?}", self)
})
}
pub fn opt_def_id(&self) -> Option<DefId> {
match *self {
Def::Fn(id) | Def::Mod(id) | Def::Static(id, _) |
Def::Variant(id) | Def::VariantCtor(id, ..) | Def::Enum(id) |
Def::TyAlias(id) | Def::TraitAlias(id) |
Def::AssociatedTy(id) | Def::TyParam(id) | Def::Struct(id) | Def::StructCtor(id, ..) |
Def::Union(id) | Def::Trait(id) | Def::Method(id) | Def::Const(id) |
Def::AssociatedConst(id) | Def::Macro(id, ..) |
Def::Existential(id) | Def::AssociatedExistential(id) | Def::ForeignTy(id) => {
Some(id)
}
Def::Local(..) |
Def::Upvar(..) |
Def::Label(..) |
Def::PrimTy(..) |
Def::SelfTy(..) |
Def::SelfCtor(..) |
Def::ToolMod |
Def::NonMacroAttr(..) |
Def::Err => {
None
}
}
}
/// A human readable kind name
pub fn kind_name(&self) -> &'static str {
match *self {
Def::Fn(..) => "function",
Def::Mod(..) => "module",
Def::Static(..) => "static",
Def::Variant(..) => "variant",
Def::VariantCtor(.., CtorKind::Fn) => "tuple variant",
Def::VariantCtor(.., CtorKind::Const) => "unit variant",
Def::VariantCtor(.., CtorKind::Fictive) => "struct variant",
Def::Enum(..) => "enum",
Def::Existential(..) => "existential type",
Def::TyAlias(..) => "type alias",
Def::TraitAlias(..) => "trait alias",
Def::AssociatedTy(..) => "associated type",
Def::AssociatedExistential(..) => "associated existential type",
Def::Struct(..) => "struct",
Def::StructCtor(.., CtorKind::Fn) => "tuple struct",
Def::StructCtor(.., CtorKind::Const) => "unit struct",
Def::StructCtor(.., CtorKind::Fictive) => bug!("impossible struct constructor"),
Def::SelfCtor(..) => "self constructor",
Def::Union(..) => "union",
Def::Trait(..) => "trait",
Def::ForeignTy(..) => "foreign type",
Def::Method(..) => "method",
Def::Const(..) => "constant",
Def::AssociatedConst(..) => "associated constant",
Def::TyParam(..) => "type parameter",
Def::PrimTy(..) => "builtin type",
Def::Local(..) => "local variable",
Def::Upvar(..) => "closure capture",
Def::Label(..) => "label",
Def::SelfTy(..) => "self type",
Def::Macro(.., macro_kind) => macro_kind.descr(),
Def::ToolMod => "tool module",
Def::NonMacroAttr(attr_kind) => attr_kind.descr(),
Def::Err => "unresolved item",
}
}
pub fn article(&self) -> &'static str {
match *self {
Def::AssociatedTy(..) | Def::AssociatedConst(..) | Def::AssociatedExistential(..) |
Def::Enum(..) | Def::Existential(..) | Def::Err => "an",
Def::Macro(.., macro_kind) => macro_kind.article(),
_ => "a",
}
}
}