hir_ty/infer/
diagnostics.rs

1//! This file contains the [`Diagnostics`] type used during inference,
2//! and a wrapper around [`TyLoweringContext`] ([`InferenceTyLoweringContext`]) that replaces
3//! it and takes care of diagnostics in inference.
4
5use std::cell::{OnceCell, RefCell};
6use std::ops::{Deref, DerefMut};
7
8use either::Either;
9use hir_def::expr_store::path::Path;
10use hir_def::{ExpressionStoreOwnerId, GenericDefId};
11use hir_def::{expr_store::ExpressionStore, type_ref::TypeRefId};
12use hir_def::{
13    hir::{ExprId, ExprOrPatIdPacked},
14    resolver::Resolver,
15};
16use la_arena::RawIdx;
17use rustc_hash::FxHashMap;
18use thin_vec::ThinVec;
19
20use crate::lower::LifetimeLoweringMode;
21use crate::{
22    InferenceDiagnostic, InferenceTyDiagnosticSource, Span, TyLoweringDiagnostic,
23    db::{AnonConstId, HirDatabase},
24    generics::Generics,
25    infer::unify::InferenceTable,
26    lower::{
27        ForbidParamsAfterReason, LifetimeElisionKind, TyLoweringContext, TyLoweringInferVarsCtx,
28        path::{PathDiagnosticCallback, PathLoweringContext},
29    },
30    next_solver::{Const, Region, StoredTy, Ty},
31};
32
33// Unfortunately, this struct needs to use interior mutability (but we encapsulate it)
34// because when lowering types and paths we hold a `TyLoweringContext` that holds a reference
35// to our resolver and so we cannot have mutable reference, but we really want to have
36// ability to dispatch diagnostics during this work otherwise the code becomes a complete mess.
37#[derive(Debug, Default, Clone)]
38pub(super) struct Diagnostics(RefCell<ThinVec<InferenceDiagnostic>>);
39
40impl Diagnostics {
41    pub(super) fn push(&self, diagnostic: InferenceDiagnostic) {
42        self.0.borrow_mut().push(diagnostic);
43    }
44
45    fn push_ty_diagnostics(
46        &self,
47        source: InferenceTyDiagnosticSource,
48        diagnostics: ThinVec<TyLoweringDiagnostic>,
49    ) {
50        self.0.borrow_mut().extend(
51            diagnostics.into_iter().map(|diag| InferenceDiagnostic::TyDiagnostic { source, diag }),
52        );
53    }
54
55    pub(super) fn finish(self) -> ThinVec<InferenceDiagnostic> {
56        self.0.into_inner()
57    }
58}
59
60pub(crate) struct PathDiagnosticCallbackData<'a> {
61    node: ExprOrPatIdPacked,
62    diagnostics: &'a Diagnostics,
63}
64
65pub(super) struct InferenceTyLoweringVarsCtx<'a, 'db> {
66    pub(super) table: &'a mut InferenceTable<'db>,
67    pub(super) type_of_type_placeholder: &'a mut FxHashMap<TypeRefId, StoredTy>,
68}
69
70impl<'db> TyLoweringInferVarsCtx<'db> for InferenceTyLoweringVarsCtx<'_, 'db> {
71    fn next_ty_var(&mut self, span: Span) -> Ty<'db> {
72        let ty = self.table.infer_ctxt.next_ty_var(span);
73
74        if let Span::TypeRefId(type_ref) = span {
75            self.type_of_type_placeholder.insert(type_ref, ty.store());
76        }
77
78        ty
79    }
80    fn next_const_var(&mut self, span: Span) -> Const<'db> {
81        self.table.infer_ctxt.next_const_var(span)
82    }
83    fn next_region_var(&mut self, span: Span) -> Region<'db> {
84        self.table.infer_ctxt.next_region_var(span)
85    }
86
87    fn as_table(&mut self) -> Option<&mut InferenceTable<'db>> {
88        Some(self.table)
89    }
90}
91
92pub(super) struct InferenceTyLoweringContext<'db, 'a> {
93    ctx: TyLoweringContext<'db, 'a>,
94    diagnostics: &'a Diagnostics,
95    source: InferenceTyDiagnosticSource,
96    defined_anon_consts: &'a RefCell<ThinVec<AnonConstId<'db>>>,
97}
98
99impl<'db, 'a> InferenceTyLoweringContext<'db, 'a> {
100    #[inline]
101    pub(super) fn new(
102        db: &'db dyn HirDatabase,
103        resolver: &'a Resolver<'db>,
104        store: &'db ExpressionStore,
105        diagnostics: &'a Diagnostics,
106        source: InferenceTyDiagnosticSource,
107        def: ExpressionStoreOwnerId,
108        generic_def: GenericDefId,
109        generics: &'a OnceCell<Generics<'db>>,
110        lifetime_elision: LifetimeElisionKind<'db>,
111        allow_using_generic_params: bool,
112        infer_vars: Option<&'a mut dyn TyLoweringInferVarsCtx<'db>>,
113        defined_anon_consts: &'a RefCell<ThinVec<AnonConstId<'db>>>,
114        lifetime_lowering_mode: LifetimeLoweringMode,
115    ) -> Self {
116        let mut ctx = TyLoweringContext::new(
117            db,
118            resolver,
119            store,
120            def,
121            generic_def,
122            generics,
123            lifetime_elision,
124            lifetime_lowering_mode,
125        )
126        .with_infer_vars_behavior(infer_vars);
127        if !allow_using_generic_params {
128            ctx.forbid_params_after(0, ForbidParamsAfterReason::AnonConst);
129        }
130        Self { ctx, diagnostics, source, defined_anon_consts }
131    }
132
133    #[inline]
134    pub(super) fn at_path<'b>(
135        &'b mut self,
136        path: &'b Path,
137        node: ExprOrPatIdPacked,
138    ) -> PathLoweringContext<'b, 'a, 'db> {
139        let on_diagnostic = PathDiagnosticCallback {
140            data: Either::Right(PathDiagnosticCallbackData { diagnostics: self.diagnostics, node }),
141            callback: |data, _, diag| {
142                let data = data.as_ref().right().unwrap();
143                data.diagnostics
144                    .push(InferenceDiagnostic::PathDiagnostic { node: data.node, diag });
145            },
146        };
147        PathLoweringContext::new(&mut self.ctx, on_diagnostic, path)
148    }
149
150    #[inline]
151    pub(super) fn at_path_forget_diagnostics<'b>(
152        &'b mut self,
153        path: &'b Path,
154    ) -> PathLoweringContext<'b, 'a, 'db> {
155        let on_diagnostic = PathDiagnosticCallback {
156            data: Either::Right(PathDiagnosticCallbackData {
157                diagnostics: self.diagnostics,
158                node: ExprOrPatIdPacked::from(ExprId::from_raw(RawIdx::from_u32(0))),
159            }),
160            callback: |_data, _, _diag| {},
161        };
162        PathLoweringContext::new(&mut self.ctx, on_diagnostic, path)
163    }
164
165    #[inline]
166    pub(super) fn forget_diagnostics(&mut self) {
167        self.ctx.diagnostics.clear();
168    }
169}
170
171impl<'db, 'a> Deref for InferenceTyLoweringContext<'db, 'a> {
172    type Target = TyLoweringContext<'db, 'a>;
173
174    #[inline]
175    fn deref(&self) -> &Self::Target {
176        &self.ctx
177    }
178}
179
180impl DerefMut for InferenceTyLoweringContext<'_, '_> {
181    #[inline]
182    fn deref_mut(&mut self) -> &mut Self::Target {
183        &mut self.ctx
184    }
185}
186
187impl Drop for InferenceTyLoweringContext<'_, '_> {
188    #[inline]
189    fn drop(&mut self) {
190        self.diagnostics
191            .push_ty_diagnostics(self.source, std::mem::take(&mut self.ctx.diagnostics));
192        self.defined_anon_consts.borrow_mut().extend(self.ctx.defined_anon_consts.iter().copied());
193    }
194}
hir_ty/infer/diagnostics.rs

hir_ty/infer/
diagnostics.rs
