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
|
//! FIXME: write short doc here
use std::sync::Arc;
use hir_def::{
path::{path, Path},
resolver::HasResolver,
AdtId, FunctionId,
};
use hir_expand::{diagnostics::DiagnosticSink, name::Name};
use ra_syntax::ast;
use ra_syntax::AstPtr;
use rustc_hash::FxHashSet;
use crate::{
db::HirDatabase,
diagnostics::{MissingFields, MissingMatchArms, MissingOkInTailExpr},
utils::variant_data,
ApplicationTy, InferenceResult, Ty, TypeCtor,
_match::{is_useful, MatchCheckCtx, Matrix, PatStack, Usefulness},
};
pub use hir_def::{
body::{
scope::{ExprScopes, ScopeEntry, ScopeId},
Body, BodySourceMap, ExprPtr, ExprSource, PatPtr, PatSource,
},
expr::{
ArithOp, Array, BinaryOp, BindingAnnotation, CmpOp, Expr, ExprId, Literal, LogicOp,
MatchArm, Ordering, Pat, PatId, RecordFieldPat, RecordLitField, Statement, UnaryOp,
},
VariantId,
};
pub struct ExprValidator<'a, 'b: 'a> {
func: FunctionId,
infer: Arc<InferenceResult>,
sink: &'a mut DiagnosticSink<'b>,
}
impl<'a, 'b> ExprValidator<'a, 'b> {
pub fn new(
func: FunctionId,
infer: Arc<InferenceResult>,
sink: &'a mut DiagnosticSink<'b>,
) -> ExprValidator<'a, 'b> {
ExprValidator { func, infer, sink }
}
pub fn validate_body(&mut self, db: &dyn HirDatabase) {
let body = db.body(self.func.into());
for e in body.exprs.iter() {
if let (id, Expr::RecordLit { path, fields, spread }) = e {
self.validate_record_literal(id, path, fields, *spread, db);
} else if let (id, Expr::Match { expr, arms }) = e {
self.validate_match(id, *expr, arms, db, self.infer.clone());
}
}
let body_expr = &body[body.body_expr];
if let Expr::Block { tail: Some(t), .. } = body_expr {
self.validate_results_in_tail_expr(body.body_expr, *t, db);
}
}
fn validate_match(
&mut self,
id: ExprId,
match_expr: ExprId,
arms: &[MatchArm],
db: &dyn HirDatabase,
infer: Arc<InferenceResult>,
) {
let (body, source_map): (Arc<Body>, Arc<BodySourceMap>) =
db.body_with_source_map(self.func.into());
let match_expr_ty = match infer.type_of_expr.get(match_expr) {
Some(ty) => ty,
// If we can't resolve the type of the match expression
// we cannot perform exhaustiveness checks.
None => return,
};
let cx = MatchCheckCtx { body, infer: infer.clone(), db };
let pats = arms.iter().map(|arm| arm.pat);
let mut seen = Matrix::empty();
for pat in pats {
// We skip any patterns whose type we cannot resolve.
//
// This could lead to false positives in this diagnostic, so
// it might be better to skip the entire diagnostic if we either
// cannot resolve a match arm or determine that the match arm has
// the wrong type.
if let Some(pat_ty) = infer.type_of_pat.get(pat) {
// We only include patterns whose type matches the type
// of the match expression. If we had a InvalidMatchArmPattern
// diagnostic or similar we could raise that in an else
// block here.
//
// When comparing the types, we also have to consider that rustc
// will automatically de-reference the match expression type if
// necessary.
//
// FIXME we should use the type checker for this.
if pat_ty == match_expr_ty
|| match_expr_ty
.as_reference()
.map(|(match_expr_ty, _)| match_expr_ty == pat_ty)
.unwrap_or(false)
{
// If we had a NotUsefulMatchArm diagnostic, we could
// check the usefulness of each pattern as we added it
// to the matrix here.
let v = PatStack::from_pattern(pat);
seen.push(&cx, v);
}
}
}
match is_useful(&cx, &seen, &PatStack::from_wild()) {
Ok(Usefulness::Useful) => (),
// if a wildcard pattern is not useful, then all patterns are covered
Ok(Usefulness::NotUseful) => return,
// this path is for unimplemented checks, so we err on the side of not
// reporting any errors
_ => return,
}
if let Ok(source_ptr) = source_map.expr_syntax(id) {
if let Some(expr) = source_ptr.value.left() {
let root = source_ptr.file_syntax(db.upcast());
if let ast::Expr::MatchExpr(match_expr) = expr.to_node(&root) {
if let (Some(match_expr), Some(arms)) =
(match_expr.expr(), match_expr.match_arm_list())
{
self.sink.push(MissingMatchArms {
file: source_ptr.file_id,
match_expr: AstPtr::new(&match_expr),
arms: AstPtr::new(&arms),
})
}
}
}
}
}
fn validate_record_literal(
&mut self,
id: ExprId,
_path: &Option<Path>,
fields: &[RecordLitField],
spread: Option<ExprId>,
db: &dyn HirDatabase,
) {
if spread.is_some() {
return;
};
let variant_def: VariantId = match self.infer.variant_resolution_for_expr(id) {
Some(VariantId::UnionId(_)) | None => return,
Some(it) => it,
};
if let VariantId::UnionId(_) = variant_def {
return;
}
let variant_data = variant_data(db.upcast(), variant_def);
let lit_fields: FxHashSet<_> = fields.iter().map(|f| &f.name).collect();
let missed_fields: Vec<Name> = variant_data
.fields()
.iter()
.filter_map(|(_f, d)| {
let name = d.name.clone();
if lit_fields.contains(&name) {
None
} else {
Some(name)
}
})
.collect();
if missed_fields.is_empty() {
return;
}
let (_, source_map) = db.body_with_source_map(self.func.into());
if let Ok(source_ptr) = source_map.expr_syntax(id) {
if let Some(expr) = source_ptr.value.left() {
let root = source_ptr.file_syntax(db.upcast());
if let ast::Expr::RecordLit(record_lit) = expr.to_node(&root) {
if let Some(field_list) = record_lit.record_field_list() {
self.sink.push(MissingFields {
file: source_ptr.file_id,
field_list: AstPtr::new(&field_list),
missed_fields,
})
}
}
}
}
}
fn validate_results_in_tail_expr(&mut self, body_id: ExprId, id: ExprId, db: &dyn HirDatabase) {
// the mismatch will be on the whole block currently
let mismatch = match self.infer.type_mismatch_for_expr(body_id) {
Some(m) => m,
None => return,
};
let std_result_path = path![std::result::Result];
let resolver = self.func.resolver(db.upcast());
let std_result_enum = match resolver.resolve_known_enum(db.upcast(), &std_result_path) {
Some(it) => it,
_ => return,
};
let std_result_ctor = TypeCtor::Adt(AdtId::EnumId(std_result_enum));
let params = match &mismatch.expected {
Ty::Apply(ApplicationTy { ctor, parameters }) if ctor == &std_result_ctor => parameters,
_ => return,
};
if params.len() == 2 && params[0] == mismatch.actual {
let (_, source_map) = db.body_with_source_map(self.func.into());
if let Ok(source_ptr) = source_map.expr_syntax(id) {
if let Some(expr) = source_ptr.value.left() {
self.sink.push(MissingOkInTailExpr { file: source_ptr.file_id, expr });
}
}
}
}
}
|
