1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
pub use self::AssocItemContainer::*;

use crate::ty;
use rustc_data_structures::sorted_map::SortedIndexMultiMap;
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Namespace};
use rustc_hir::def_id::DefId;
use rustc_span::symbol::{Ident, Symbol};

use super::{TyCtxt, Visibility};

#[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable, Hash, Encodable, Decodable)]
pub enum AssocItemContainer {
    TraitContainer(DefId),
    ImplContainer(DefId),
}

impl AssocItemContainer {
    pub fn impl_def_id(&self) -> Option<DefId> {
        match *self {
            ImplContainer(id) => Some(id),
            _ => None,
        }
    }

    /// Asserts that this is the `DefId` of an associated item declared
    /// in a trait, and returns the trait `DefId`.
    pub fn assert_trait(&self) -> DefId {
        match *self {
            TraitContainer(id) => id,
            _ => bug!("associated item has wrong container type: {:?}", self),
        }
    }

    pub fn id(&self) -> DefId {
        match *self {
            TraitContainer(id) => id,
            ImplContainer(id) => id,
        }
    }
}

/// Information about an associated item
#[derive(Copy, Clone, Debug, PartialEq, HashStable, Eq, Hash, Encodable, Decodable)]
pub struct AssocItem {
    pub def_id: DefId,
    pub name: Symbol,
    pub kind: AssocKind,
    pub vis: Visibility,
    pub defaultness: hir::Defaultness,
    pub container: AssocItemContainer,

    /// If this is an item in an impl of a trait then this is the `DefId` of
    /// the associated item on the trait that this implements.
    pub trait_item_def_id: Option<DefId>,

    /// Whether this is a method with an explicit self
    /// as its first parameter, allowing method calls.
    pub fn_has_self_parameter: bool,
}

impl AssocItem {
    pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
        Ident::new(self.name, tcx.def_ident_span(self.def_id).unwrap())
    }

    pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
        match self.kind {
            ty::AssocKind::Fn => {
                // We skip the binder here because the binder would deanonymize all
                // late-bound regions, and we don't want method signatures to show up
                // `as for<'r> fn(&'r MyType)`.  Pretty-printing handles late-bound
                // regions just fine, showing `fn(&MyType)`.
                tcx.fn_sig(self.def_id).skip_binder().to_string()
            }
            ty::AssocKind::Type => format!("type {};", self.name),
            ty::AssocKind::Const => {
                format!("const {}: {:?};", self.name, tcx.type_of(self.def_id))
            }
        }
    }
}

#[derive(Copy, Clone, PartialEq, Debug, HashStable, Eq, Hash, Encodable, Decodable)]
pub enum AssocKind {
    Const,
    Fn,
    Type,
}

impl AssocKind {
    pub fn namespace(&self) -> Namespace {
        match *self {
            ty::AssocKind::Type => Namespace::TypeNS,
            ty::AssocKind::Const | ty::AssocKind::Fn => Namespace::ValueNS,
        }
    }

    pub fn as_def_kind(&self) -> DefKind {
        match self {
            AssocKind::Const => DefKind::AssocConst,
            AssocKind::Fn => DefKind::AssocFn,
            AssocKind::Type => DefKind::AssocTy,
        }
    }
}

/// A list of `ty::AssocItem`s in definition order that allows for efficient lookup by name.
///
/// When doing lookup by name, we try to postpone hygienic comparison for as long as possible since
/// it is relatively expensive. Instead, items are indexed by `Symbol` and hygienic comparison is
/// done only on items with the same name.
#[derive(Debug, Clone, PartialEq, HashStable)]
pub struct AssocItems<'tcx> {
    pub(super) items: SortedIndexMultiMap<u32, Symbol, &'tcx ty::AssocItem>,
}

impl<'tcx> AssocItems<'tcx> {
    /// Constructs an `AssociatedItems` map from a series of `ty::AssocItem`s in definition order.
    pub fn new(items_in_def_order: impl IntoIterator<Item = &'tcx ty::AssocItem>) -> Self {
        let items = items_in_def_order.into_iter().map(|item| (item.name, item)).collect();
        AssocItems { items }
    }

    /// Returns a slice of associated items in the order they were defined.
    ///
    /// New code should avoid relying on definition order. If you need a particular associated item
    /// for a known trait, make that trait a lang item instead of indexing this array.
    pub fn in_definition_order(&self) -> impl '_ + Iterator<Item = &ty::AssocItem> {
        self.items.iter().map(|(_, v)| *v)
    }

    pub fn len(&self) -> usize {
        self.items.len()
    }

    /// Returns an iterator over all associated items with the given name, ignoring hygiene.
    pub fn filter_by_name_unhygienic(
        &self,
        name: Symbol,
    ) -> impl '_ + Iterator<Item = &ty::AssocItem> {
        self.items.get_by_key(name).copied()
    }

    /// Returns the associated item with the given name and `AssocKind`, if one exists.
    pub fn find_by_name_and_kind(
        &self,
        tcx: TyCtxt<'_>,
        ident: Ident,
        kind: AssocKind,
        parent_def_id: DefId,
    ) -> Option<&ty::AssocItem> {
        self.filter_by_name_unhygienic(ident.name)
            .filter(|item| item.kind == kind)
            .find(|item| tcx.hygienic_eq(ident, item.ident(tcx), parent_def_id))
    }

    /// Returns the associated item with the given name and any of `AssocKind`, if one exists.
    pub fn find_by_name_and_kinds(
        &self,
        tcx: TyCtxt<'_>,
        ident: Ident,
        // Sorted in order of what kinds to look at
        kinds: &[AssocKind],
        parent_def_id: DefId,
    ) -> Option<&ty::AssocItem> {
        kinds.iter().find_map(|kind| self.find_by_name_and_kind(tcx, ident, *kind, parent_def_id))
    }

    /// Returns the associated item with the given name in the given `Namespace`, if one exists.
    pub fn find_by_name_and_namespace(
        &self,
        tcx: TyCtxt<'_>,
        ident: Ident,
        ns: Namespace,
        parent_def_id: DefId,
    ) -> Option<&ty::AssocItem> {
        self.filter_by_name_unhygienic(ident.name)
            .filter(|item| item.kind.namespace() == ns)
            .find(|item| tcx.hygienic_eq(ident, item.ident(tcx), parent_def_id))
    }
}