summaryrefslogtreecommitdiffstats
path: root/compiler/rustc_resolve/src/def_collector.rs
blob: 3f88f44ff21a331a1b3233001ac4e21d91021997 (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
340
341
342
343
344
345
346
347
348
349
350
351
352
353
use crate::{ImplTraitContext, Resolver};
use rustc_ast::visit::{self, FnKind};
use rustc_ast::walk_list;
use rustc_ast::*;
use rustc_expand::expand::AstFragment;
use rustc_hir::def_id::LocalDefId;
use rustc_hir::definitions::*;
use rustc_span::hygiene::LocalExpnId;
use rustc_span::symbol::sym;
use rustc_span::Span;

pub(crate) fn collect_definitions(
    resolver: &mut Resolver<'_>,
    fragment: &AstFragment,
    expansion: LocalExpnId,
) {
    let (parent_def, impl_trait_context) = resolver.invocation_parents[&expansion];
    fragment.visit_with(&mut DefCollector { resolver, parent_def, expansion, impl_trait_context });
}

/// Creates `DefId`s for nodes in the AST.
struct DefCollector<'a, 'b> {
    resolver: &'a mut Resolver<'b>,
    parent_def: LocalDefId,
    impl_trait_context: ImplTraitContext,
    expansion: LocalExpnId,
}

impl<'a, 'b> DefCollector<'a, 'b> {
    fn create_def(&mut self, node_id: NodeId, data: DefPathData, span: Span) -> LocalDefId {
        let parent_def = self.parent_def;
        debug!("create_def(node_id={:?}, data={:?}, parent_def={:?})", node_id, data, parent_def);
        self.resolver.create_def(
            parent_def,
            node_id,
            data,
            self.expansion.to_expn_id(),
            span.with_parent(None),
        )
    }

    fn with_parent<F: FnOnce(&mut Self)>(&mut self, parent_def: LocalDefId, f: F) {
        let orig_parent_def = std::mem::replace(&mut self.parent_def, parent_def);
        f(self);
        self.parent_def = orig_parent_def;
    }

    fn with_impl_trait<F: FnOnce(&mut Self)>(
        &mut self,
        impl_trait_context: ImplTraitContext,
        f: F,
    ) {
        let orig_itc = std::mem::replace(&mut self.impl_trait_context, impl_trait_context);
        f(self);
        self.impl_trait_context = orig_itc;
    }

    fn collect_field(&mut self, field: &'a FieldDef, index: Option<usize>) {
        let index = |this: &Self| {
            index.unwrap_or_else(|| {
                let node_id = NodeId::placeholder_from_expn_id(this.expansion);
                this.resolver.placeholder_field_indices[&node_id]
            })
        };

        if field.is_placeholder {
            let old_index = self.resolver.placeholder_field_indices.insert(field.id, index(self));
            assert!(old_index.is_none(), "placeholder field index is reset for a node ID");
            self.visit_macro_invoc(field.id);
        } else {
            let name = field.ident.map_or_else(|| sym::integer(index(self)), |ident| ident.name);
            let def = self.create_def(field.id, DefPathData::ValueNs(name), field.span);
            self.with_parent(def, |this| visit::walk_field_def(this, field));
        }
    }

    fn visit_macro_invoc(&mut self, id: NodeId) {
        let id = id.placeholder_to_expn_id();
        let old_parent =
            self.resolver.invocation_parents.insert(id, (self.parent_def, self.impl_trait_context));
        assert!(old_parent.is_none(), "parent `LocalDefId` is reset for an invocation");
    }
}

impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
    fn visit_item(&mut self, i: &'a Item) {
        debug!("visit_item: {:?}", i);

        // Pick the def data. This need not be unique, but the more
        // information we encapsulate into, the better
        let def_data = match &i.kind {
            ItemKind::Impl { .. } => DefPathData::Impl,
            ItemKind::ForeignMod(..) => DefPathData::ForeignMod,
            ItemKind::Mod(..)
            | ItemKind::Trait(..)
            | ItemKind::TraitAlias(..)
            | ItemKind::Enum(..)
            | ItemKind::Struct(..)
            | ItemKind::Union(..)
            | ItemKind::ExternCrate(..)
            | ItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
            ItemKind::Static(..) | ItemKind::Const(..) | ItemKind::Fn(..) => {
                DefPathData::ValueNs(i.ident.name)
            }
            ItemKind::MacroDef(..) => DefPathData::MacroNs(i.ident.name),
            ItemKind::MacCall(..) => {
                visit::walk_item(self, i);
                return self.visit_macro_invoc(i.id);
            }
            ItemKind::GlobalAsm(..) => DefPathData::GlobalAsm,
            ItemKind::Use(..) => {
                return visit::walk_item(self, i);
            }
        };
        let def = self.create_def(i.id, def_data, i.span);

        self.with_parent(def, |this| {
            this.with_impl_trait(ImplTraitContext::Existential, |this| {
                match i.kind {
                    ItemKind::Struct(ref struct_def, _) | ItemKind::Union(ref struct_def, _) => {
                        // If this is a unit or tuple-like struct, register the constructor.
                        if let Some(ctor_hir_id) = struct_def.ctor_id() {
                            this.create_def(ctor_hir_id, DefPathData::Ctor, i.span);
                        }
                    }
                    _ => {}
                }
                visit::walk_item(this, i);
            })
        });
    }

    fn visit_fn(&mut self, fn_kind: FnKind<'a>, span: Span, _: NodeId) {
        if let FnKind::Fn(_, _, sig, _, generics, body) = fn_kind {
            if let Async::Yes { closure_id, return_impl_trait_id, .. } = sig.header.asyncness {
                self.visit_generics(generics);

                let return_impl_trait_id =
                    self.create_def(return_impl_trait_id, DefPathData::ImplTrait, span);

                // For async functions, we need to create their inner defs inside of a
                // closure to match their desugared representation. Besides that,
                // we must mirror everything that `visit::walk_fn` below does.
                self.visit_fn_header(&sig.header);
                for param in &sig.decl.inputs {
                    self.visit_param(param);
                }
                self.with_parent(return_impl_trait_id, |this| {
                    this.visit_fn_ret_ty(&sig.decl.output)
                });
                let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
                self.with_parent(closure_def, |this| walk_list!(this, visit_block, body));
                return;
            }
        }

        visit::walk_fn(self, fn_kind);
    }

    fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
        self.create_def(id, DefPathData::Use, use_tree.span);
        match use_tree.kind {
            UseTreeKind::Simple(_, id1, id2) => {
                self.create_def(id1, DefPathData::Use, use_tree.prefix.span);
                self.create_def(id2, DefPathData::Use, use_tree.prefix.span);
            }
            UseTreeKind::Glob => (),
            UseTreeKind::Nested(..) => {}
        }
        visit::walk_use_tree(self, use_tree, id);
    }

    fn visit_foreign_item(&mut self, foreign_item: &'a ForeignItem) {
        if let ForeignItemKind::MacCall(_) = foreign_item.kind {
            return self.visit_macro_invoc(foreign_item.id);
        }

        let def = self.create_def(
            foreign_item.id,
            DefPathData::ValueNs(foreign_item.ident.name),
            foreign_item.span,
        );

        self.with_parent(def, |this| {
            visit::walk_foreign_item(this, foreign_item);
        });
    }

    fn visit_variant(&mut self, v: &'a Variant) {
        if v.is_placeholder {
            return self.visit_macro_invoc(v.id);
        }
        let def = self.create_def(v.id, DefPathData::TypeNs(v.ident.name), v.span);
        self.with_parent(def, |this| {
            if let Some(ctor_hir_id) = v.data.ctor_id() {
                this.create_def(ctor_hir_id, DefPathData::Ctor, v.span);
            }
            visit::walk_variant(this, v)
        });
    }

    fn visit_variant_data(&mut self, data: &'a VariantData) {
        // The assumption here is that non-`cfg` macro expansion cannot change field indices.
        // It currently holds because only inert attributes are accepted on fields,
        // and every such attribute expands into a single field after it's resolved.
        for (index, field) in data.fields().iter().enumerate() {
            self.collect_field(field, Some(index));
        }
    }

    fn visit_generic_param(&mut self, param: &'a GenericParam) {
        if param.is_placeholder {
            self.visit_macro_invoc(param.id);
            return;
        }
        let name = param.ident.name;
        let def_path_data = match param.kind {
            GenericParamKind::Lifetime { .. } => DefPathData::LifetimeNs(name),
            GenericParamKind::Type { .. } => DefPathData::TypeNs(name),
            GenericParamKind::Const { .. } => DefPathData::ValueNs(name),
        };
        self.create_def(param.id, def_path_data, param.ident.span);

        // impl-Trait can happen inside generic parameters, like
        // ```
        // fn foo<U: Iterator<Item = impl Clone>>() {}
        // ```
        //
        // In that case, the impl-trait is lowered as an additional generic parameter.
        self.with_impl_trait(ImplTraitContext::Universal(self.parent_def), |this| {
            visit::walk_generic_param(this, param)
        });
    }

    fn visit_assoc_item(&mut self, i: &'a AssocItem, ctxt: visit::AssocCtxt) {
        let def_data = match &i.kind {
            AssocItemKind::Fn(..) | AssocItemKind::Const(..) => DefPathData::ValueNs(i.ident.name),
            AssocItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
            AssocItemKind::MacCall(..) => return self.visit_macro_invoc(i.id),
        };

        let def = self.create_def(i.id, def_data, i.span);
        self.with_parent(def, |this| visit::walk_assoc_item(this, i, ctxt));
    }

    fn visit_pat(&mut self, pat: &'a Pat) {
        match pat.kind {
            PatKind::MacCall(..) => self.visit_macro_invoc(pat.id),
            _ => visit::walk_pat(self, pat),
        }
    }

    fn visit_anon_const(&mut self, constant: &'a AnonConst) {
        let def = self.create_def(constant.id, DefPathData::AnonConst, constant.value.span);
        self.with_parent(def, |this| visit::walk_anon_const(this, constant));
    }

    fn visit_expr(&mut self, expr: &'a Expr) {
        let parent_def = match expr.kind {
            ExprKind::MacCall(..) => return self.visit_macro_invoc(expr.id),
            ExprKind::Closure(_, _, asyncness, ..) => {
                // Async closures desugar to closures inside of closures, so
                // we must create two defs.
                let closure_def = self.create_def(expr.id, DefPathData::ClosureExpr, expr.span);
                match asyncness {
                    Async::Yes { closure_id, .. } => {
                        self.create_def(closure_id, DefPathData::ClosureExpr, expr.span)
                    }
                    Async::No => closure_def,
                }
            }
            ExprKind::Async(_, async_id, _) => {
                self.create_def(async_id, DefPathData::ClosureExpr, expr.span)
            }
            _ => self.parent_def,
        };

        self.with_parent(parent_def, |this| visit::walk_expr(this, expr));
    }

    fn visit_ty(&mut self, ty: &'a Ty) {
        match ty.kind {
            TyKind::MacCall(..) => self.visit_macro_invoc(ty.id),
            TyKind::ImplTrait(node_id, _) => {
                let parent_def = match self.impl_trait_context {
                    ImplTraitContext::Universal(item_def) => self.resolver.create_def(
                        item_def,
                        node_id,
                        DefPathData::ImplTrait,
                        self.expansion.to_expn_id(),
                        ty.span,
                    ),
                    ImplTraitContext::Existential => {
                        self.create_def(node_id, DefPathData::ImplTrait, ty.span)
                    }
                };
                self.with_parent(parent_def, |this| visit::walk_ty(this, ty))
            }
            _ => visit::walk_ty(self, ty),
        }
    }

    fn visit_stmt(&mut self, stmt: &'a Stmt) {
        match stmt.kind {
            StmtKind::MacCall(..) => self.visit_macro_invoc(stmt.id),
            _ => visit::walk_stmt(self, stmt),
        }
    }

    fn visit_arm(&mut self, arm: &'a Arm) {
        if arm.is_placeholder { self.visit_macro_invoc(arm.id) } else { visit::walk_arm(self, arm) }
    }

    fn visit_expr_field(&mut self, f: &'a ExprField) {
        if f.is_placeholder {
            self.visit_macro_invoc(f.id)
        } else {
            visit::walk_expr_field(self, f)
        }
    }

    fn visit_pat_field(&mut self, fp: &'a PatField) {
        if fp.is_placeholder {
            self.visit_macro_invoc(fp.id)
        } else {
            visit::walk_pat_field(self, fp)
        }
    }

    fn visit_param(&mut self, p: &'a Param) {
        if p.is_placeholder {
            self.visit_macro_invoc(p.id)
        } else {
            self.with_impl_trait(ImplTraitContext::Universal(self.parent_def), |this| {
                visit::walk_param(this, p)
            })
        }
    }

    // This method is called only when we are visiting an individual field
    // after expanding an attribute on it.
    fn visit_field_def(&mut self, field: &'a FieldDef) {
        self.collect_field(field, None);
    }

    fn visit_crate(&mut self, krate: &'a Crate) {
        if krate.is_placeholder {
            self.visit_macro_invoc(krate.id)
        } else {
            visit::walk_crate(self, krate)
        }
    }
}