hir_def/
lower.rs

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1//! Context for lowering paths.
2use std::{cell::OnceCell, mem};
3
4use hir_expand::{AstId, HirFileId, InFile, span_map::SpanMap};
5use span::{AstIdMap, AstIdNode, Edition, EditionedFileId, FileId, RealSpanMap};
6use syntax::ast;
7use thin_vec::ThinVec;
8use triomphe::Arc;
9
10use crate::{
11    db::DefDatabase,
12    path::Path,
13    type_ref::{PathId, TypeBound, TypePtr, TypeRef, TypeRefId, TypesMap, TypesSourceMap},
14};
15
16pub struct LowerCtx<'a> {
17    pub db: &'a dyn DefDatabase,
18    file_id: HirFileId,
19    span_map: OnceCell<SpanMap>,
20    ast_id_map: OnceCell<Arc<AstIdMap>>,
21    impl_trait_bounds: Vec<ThinVec<TypeBound>>,
22    // Prevent nested impl traits like `impl Foo<impl Bar>`.
23    outer_impl_trait: bool,
24    types_map: &'a mut TypesMap,
25    types_source_map: &'a mut TypesSourceMap,
26}
27
28impl<'a> LowerCtx<'a> {
29    pub fn new(
30        db: &'a dyn DefDatabase,
31        file_id: HirFileId,
32        types_map: &'a mut TypesMap,
33        types_source_map: &'a mut TypesSourceMap,
34    ) -> Self {
35        LowerCtx {
36            db,
37            file_id,
38            span_map: OnceCell::new(),
39            ast_id_map: OnceCell::new(),
40            impl_trait_bounds: Vec::new(),
41            outer_impl_trait: false,
42            types_map,
43            types_source_map,
44        }
45    }
46
47    pub fn with_span_map_cell(
48        db: &'a dyn DefDatabase,
49        file_id: HirFileId,
50        span_map: OnceCell<SpanMap>,
51        types_map: &'a mut TypesMap,
52        types_source_map: &'a mut TypesSourceMap,
53    ) -> Self {
54        LowerCtx {
55            db,
56            file_id,
57            span_map,
58            ast_id_map: OnceCell::new(),
59            impl_trait_bounds: Vec::new(),
60            outer_impl_trait: false,
61            types_map,
62            types_source_map,
63        }
64    }
65
66    /// Prepares a `LowerCtx` for synthetic AST that needs to be lowered. This is intended for IDE things.
67    pub fn for_synthetic_ast(
68        db: &'a dyn DefDatabase,
69        ast_id_map: Arc<AstIdMap>,
70        types_map: &'a mut TypesMap,
71        types_source_map: &'a mut TypesSourceMap,
72    ) -> Self {
73        let file_id = EditionedFileId::new(
74            FileId::from_raw(EditionedFileId::MAX_FILE_ID),
75            Edition::Edition2015,
76        );
77        LowerCtx {
78            db,
79            // Make up an invalid file id, so that if we will try to actually access it salsa will panic.
80            file_id: file_id.into(),
81            span_map: SpanMap::RealSpanMap(Arc::new(RealSpanMap::absolute(file_id))).into(),
82            ast_id_map: ast_id_map.into(),
83            impl_trait_bounds: Vec::new(),
84            outer_impl_trait: false,
85            types_map,
86            types_source_map,
87        }
88    }
89
90    pub(crate) fn span_map(&self) -> &SpanMap {
91        self.span_map.get_or_init(|| self.db.span_map(self.file_id))
92    }
93
94    pub(crate) fn lower_path(&mut self, ast: ast::Path) -> Option<Path> {
95        Path::from_src(self, ast)
96    }
97
98    pub(crate) fn ast_id<N: AstIdNode>(&self, item: &N) -> AstId<N> {
99        InFile::new(
100            self.file_id,
101            self.ast_id_map.get_or_init(|| self.db.ast_id_map(self.file_id)).ast_id(item),
102        )
103    }
104
105    pub fn update_impl_traits_bounds_from_type_ref(&mut self, type_ref: TypeRefId) {
106        TypeRef::walk(type_ref, self.types_map, &mut |tr| {
107            if let TypeRef::ImplTrait(bounds) = tr {
108                self.impl_trait_bounds.push(bounds.clone());
109            }
110        });
111    }
112
113    pub fn take_impl_traits_bounds(&mut self) -> Vec<ThinVec<TypeBound>> {
114        mem::take(&mut self.impl_trait_bounds)
115    }
116
117    pub(crate) fn outer_impl_trait(&self) -> bool {
118        self.outer_impl_trait
119    }
120
121    pub(crate) fn with_outer_impl_trait_scope<R>(
122        &mut self,
123        impl_trait: bool,
124        f: impl FnOnce(&mut Self) -> R,
125    ) -> R {
126        let old = mem::replace(&mut self.outer_impl_trait, impl_trait);
127        let result = f(self);
128        self.outer_impl_trait = old;
129        result
130    }
131
132    pub(crate) fn alloc_type_ref(&mut self, type_ref: TypeRef, node: TypePtr) -> TypeRefId {
133        let id = self.types_map.types.alloc(type_ref);
134        self.types_source_map.types_map_back.insert(id, InFile::new(self.file_id, node));
135        id
136    }
137
138    pub(crate) fn alloc_type_ref_desugared(&mut self, type_ref: TypeRef) -> TypeRefId {
139        self.types_map.types.alloc(type_ref)
140    }
141
142    pub(crate) fn alloc_error_type(&mut self) -> TypeRefId {
143        self.types_map.types.alloc(TypeRef::Error)
144    }
145
146    pub(crate) fn alloc_path(&mut self, path: Path, node: TypePtr) -> PathId {
147        PathId::from_type_ref_unchecked(self.alloc_type_ref(TypeRef::Path(path), node))
148    }
149}
hir_def/lower.rs

hir_def/
lower.rs
