aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_hir_def/src/generics.rs
blob: 0e06a0b12e809be9ac6d6881341400a3f2ec7395 (plain)
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
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
//! Many kinds of items or constructs can have generic parameters: functions,
//! structs, impls, traits, etc. This module provides a common HIR for these
//! generic parameters. See also the `Generics` type and the `generics_of` query
//! in rustc.
use std::sync::Arc;

use arena::{map::ArenaMap, Arena};
use either::Either;
use hir_expand::{
    name::{name, AsName, Name},
    InFile,
};
use ra_db::FileId;
use ra_syntax::ast::{self, GenericParamsOwner, NameOwner, TypeBoundsOwner};

use crate::{
    body::LowerCtx,
    child_by_source::ChildBySource,
    db::DefDatabase,
    dyn_map::DynMap,
    keys,
    src::HasChildSource,
    src::HasSource,
    type_ref::{TypeBound, TypeRef},
    AdtId, GenericDefId, LocalTypeParamId, Lookup, TypeParamId,
};

/// Data about a generic parameter (to a function, struct, impl, ...).
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct TypeParamData {
    pub name: Option<Name>,
    pub default: Option<TypeRef>,
    pub provenance: TypeParamProvenance,
}

#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum TypeParamProvenance {
    TypeParamList,
    TraitSelf,
    ArgumentImplTrait,
}

/// Data about the generic parameters of a function, struct, impl, etc.
#[derive(Clone, PartialEq, Eq, Debug, Default)]
pub struct GenericParams {
    pub types: Arena<TypeParamData>,
    // lifetimes: Arena<LocalLifetimeParamId, LifetimeParamData>,
    pub where_predicates: Vec<WherePredicate>,
}

/// A single predicate from a where clause, i.e. `where Type: Trait`. Combined
/// where clauses like `where T: Foo + Bar` are turned into multiple of these.
/// It might still result in multiple actual predicates though, because of
/// associated type bindings like `Iterator<Item = u32>`.
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct WherePredicate {
    pub target: WherePredicateTarget,
    pub bound: TypeBound,
}

#[derive(Clone, PartialEq, Eq, Debug)]
pub enum WherePredicateTarget {
    TypeRef(TypeRef),
    /// For desugared where predicates that can directly refer to a type param.
    TypeParam(LocalTypeParamId),
}

type SourceMap = ArenaMap<LocalTypeParamId, Either<ast::Trait, ast::TypeParam>>;

impl GenericParams {
    pub(crate) fn generic_params_query(
        db: &dyn DefDatabase,
        def: GenericDefId,
    ) -> Arc<GenericParams> {
        let _p = profile::span("generic_params_query");

        let generics = match def {
            GenericDefId::FunctionId(id) => {
                let id = id.lookup(db).id;
                let tree = db.item_tree(id.file_id);
                let item = &tree[id.value];
                tree[item.generic_params].clone()
            }
            GenericDefId::AdtId(AdtId::StructId(id)) => {
                let id = id.lookup(db).id;
                let tree = db.item_tree(id.file_id);
                let item = &tree[id.value];
                tree[item.generic_params].clone()
            }
            GenericDefId::AdtId(AdtId::EnumId(id)) => {
                let id = id.lookup(db).id;
                let tree = db.item_tree(id.file_id);
                let item = &tree[id.value];
                tree[item.generic_params].clone()
            }
            GenericDefId::AdtId(AdtId::UnionId(id)) => {
                let id = id.lookup(db).id;
                let tree = db.item_tree(id.file_id);
                let item = &tree[id.value];
                tree[item.generic_params].clone()
            }
            GenericDefId::TraitId(id) => {
                let id = id.lookup(db).id;
                let tree = db.item_tree(id.file_id);
                let item = &tree[id.value];
                tree[item.generic_params].clone()
            }
            GenericDefId::TypeAliasId(id) => {
                let id = id.lookup(db).id;
                let tree = db.item_tree(id.file_id);
                let item = &tree[id.value];
                tree[item.generic_params].clone()
            }
            GenericDefId::ImplId(id) => {
                let id = id.lookup(db).id;
                let tree = db.item_tree(id.file_id);
                let item = &tree[id.value];
                tree[item.generic_params].clone()
            }
            GenericDefId::EnumVariantId(_) | GenericDefId::ConstId(_) => GenericParams::default(),
        };
        Arc::new(generics)
    }

    fn new(db: &dyn DefDatabase, def: GenericDefId) -> (GenericParams, InFile<SourceMap>) {
        let mut generics = GenericParams { types: Arena::default(), where_predicates: Vec::new() };
        let mut sm = ArenaMap::default();

        // FIXME: add `: Sized` bound for everything except for `Self` in traits
        let file_id = match def {
            GenericDefId::FunctionId(it) => {
                let src = it.lookup(db).source(db);
                let lower_ctx = LowerCtx::new(db, src.file_id);
                generics.fill(&lower_ctx, &mut sm, &src.value);
                // lower `impl Trait` in arguments
                let data = db.function_data(it);
                for param in &data.params {
                    generics.fill_implicit_impl_trait_args(param);
                }
                src.file_id
            }
            GenericDefId::AdtId(AdtId::StructId(it)) => {
                let src = it.lookup(db).source(db);
                let lower_ctx = LowerCtx::new(db, src.file_id);
                generics.fill(&lower_ctx, &mut sm, &src.value);
                src.file_id
            }
            GenericDefId::AdtId(AdtId::UnionId(it)) => {
                let src = it.lookup(db).source(db);
                let lower_ctx = LowerCtx::new(db, src.file_id);
                generics.fill(&lower_ctx, &mut sm, &src.value);
                src.file_id
            }
            GenericDefId::AdtId(AdtId::EnumId(it)) => {
                let src = it.lookup(db).source(db);
                let lower_ctx = LowerCtx::new(db, src.file_id);
                generics.fill(&lower_ctx, &mut sm, &src.value);
                src.file_id
            }
            GenericDefId::TraitId(it) => {
                let src = it.lookup(db).source(db);
                let lower_ctx = LowerCtx::new(db, src.file_id);

                // traits get the Self type as an implicit first type parameter
                let self_param_id = generics.types.alloc(TypeParamData {
                    name: Some(name![Self]),
                    default: None,
                    provenance: TypeParamProvenance::TraitSelf,
                });
                sm.insert(self_param_id, Either::Left(src.value.clone()));
                // add super traits as bounds on Self
                // i.e., trait Foo: Bar is equivalent to trait Foo where Self: Bar
                let self_param = TypeRef::Path(name![Self].into());
                generics.fill_bounds(&lower_ctx, &src.value, self_param);

                generics.fill(&lower_ctx, &mut sm, &src.value);
                src.file_id
            }
            GenericDefId::TypeAliasId(it) => {
                let src = it.lookup(db).source(db);
                let lower_ctx = LowerCtx::new(db, src.file_id);

                generics.fill(&lower_ctx, &mut sm, &src.value);
                src.file_id
            }
            // Note that we don't add `Self` here: in `impl`s, `Self` is not a
            // type-parameter, but rather is a type-alias for impl's target
            // type, so this is handled by the resolver.
            GenericDefId::ImplId(it) => {
                let src = it.lookup(db).source(db);
                let lower_ctx = LowerCtx::new(db, src.file_id);

                generics.fill(&lower_ctx, &mut sm, &src.value);
                src.file_id
            }
            // We won't be using this ID anyway
            GenericDefId::EnumVariantId(_) | GenericDefId::ConstId(_) => FileId(!0).into(),
        };

        (generics, InFile::new(file_id, sm))
    }

    pub(crate) fn fill(
        &mut self,
        lower_ctx: &LowerCtx,
        sm: &mut SourceMap,
        node: &dyn GenericParamsOwner,
    ) {
        if let Some(params) = node.generic_param_list() {
            self.fill_params(lower_ctx, sm, params)
        }
        if let Some(where_clause) = node.where_clause() {
            self.fill_where_predicates(lower_ctx, where_clause);
        }
    }

    pub(crate) fn fill_bounds(
        &mut self,
        lower_ctx: &LowerCtx,
        node: &dyn ast::TypeBoundsOwner,
        type_ref: TypeRef,
    ) {
        for bound in
            node.type_bound_list().iter().flat_map(|type_bound_list| type_bound_list.bounds())
        {
            self.add_where_predicate_from_bound(lower_ctx, bound, type_ref.clone());
        }
    }

    fn fill_params(
        &mut self,
        lower_ctx: &LowerCtx,
        sm: &mut SourceMap,
        params: ast::GenericParamList,
    ) {
        for type_param in params.type_params() {
            let name = type_param.name().map_or_else(Name::missing, |it| it.as_name());
            // FIXME: Use `Path::from_src`
            let default = type_param.default_type().map(|it| TypeRef::from_ast(lower_ctx, it));
            let param = TypeParamData {
                name: Some(name.clone()),
                default,
                provenance: TypeParamProvenance::TypeParamList,
            };
            let param_id = self.types.alloc(param);
            sm.insert(param_id, Either::Right(type_param.clone()));

            let type_ref = TypeRef::Path(name.into());
            self.fill_bounds(&lower_ctx, &type_param, type_ref);
        }
    }

    fn fill_where_predicates(&mut self, lower_ctx: &LowerCtx, where_clause: ast::WhereClause) {
        for pred in where_clause.predicates() {
            let type_ref = match pred.ty() {
                Some(type_ref) => type_ref,
                None => continue,
            };
            let type_ref = TypeRef::from_ast(lower_ctx, type_ref);
            for bound in pred.type_bound_list().iter().flat_map(|l| l.bounds()) {
                self.add_where_predicate_from_bound(lower_ctx, bound, type_ref.clone());
            }
        }
    }

    fn add_where_predicate_from_bound(
        &mut self,
        lower_ctx: &LowerCtx,
        bound: ast::TypeBound,
        type_ref: TypeRef,
    ) {
        if bound.question_mark_token().is_some() {
            // FIXME: remove this bound
            return;
        }
        let bound = TypeBound::from_ast(lower_ctx, bound);
        self.where_predicates
            .push(WherePredicate { target: WherePredicateTarget::TypeRef(type_ref), bound });
    }

    pub(crate) fn fill_implicit_impl_trait_args(&mut self, type_ref: &TypeRef) {
        type_ref.walk(&mut |type_ref| {
            if let TypeRef::ImplTrait(bounds) = type_ref {
                let param = TypeParamData {
                    name: None,
                    default: None,
                    provenance: TypeParamProvenance::ArgumentImplTrait,
                };
                let param_id = self.types.alloc(param);
                for bound in bounds {
                    self.where_predicates.push(WherePredicate {
                        target: WherePredicateTarget::TypeParam(param_id),
                        bound: bound.clone(),
                    });
                }
            }
        });
    }

    pub fn find_by_name(&self, name: &Name) -> Option<LocalTypeParamId> {
        self.types
            .iter()
            .find_map(|(id, p)| if p.name.as_ref() == Some(name) { Some(id) } else { None })
    }

    pub fn find_trait_self_param(&self) -> Option<LocalTypeParamId> {
        self.types.iter().find_map(|(id, p)| {
            if p.provenance == TypeParamProvenance::TraitSelf {
                Some(id)
            } else {
                None
            }
        })
    }
}

impl HasChildSource for GenericDefId {
    type ChildId = LocalTypeParamId;
    type Value = Either<ast::Trait, ast::TypeParam>;
    fn child_source(&self, db: &dyn DefDatabase) -> InFile<SourceMap> {
        let (_, sm) = GenericParams::new(db, *self);
        sm
    }
}

impl ChildBySource for GenericDefId {
    fn child_by_source(&self, db: &dyn DefDatabase) -> DynMap {
        let mut res = DynMap::default();
        let arena_map = self.child_source(db);
        let arena_map = arena_map.as_ref();
        for (local_id, src) in arena_map.value.iter() {
            let id = TypeParamId { parent: *self, local_id };
            if let Either::Right(type_param) = src {
                res[keys::TYPE_PARAM].insert(arena_map.with_value(type_param.clone()), id)
            }
        }
        res
    }
}