diff options
author | bors[bot] <26634292+bors[bot]@users.noreply.github.com> | 2020-07-14 09:30:07 +0100 |
---|---|---|
committer | GitHub <[email protected]> | 2020-07-14 09:30:07 +0100 |
commit | 612112a2c26ec61bf341f99e9e7753bb41873fc4 (patch) | |
tree | c2becab63418e6ffd88af4bfdd1b129b305cff6d /crates/ra_hir_ty/src/diagnostics | |
parent | a34f79b17412f83242283fae6e7a6275b4056611 (diff) | |
parent | 19450534cf308eff30ea7de1a40ab77dca4e6014 (diff) |
Merge #5358
5358: Cleanup hir diagnostics API r=matklad a=matklad
bors r+
🤖
Co-authored-by: Aleksey Kladov <[email protected]>
Diffstat (limited to 'crates/ra_hir_ty/src/diagnostics')
-rw-r--r-- | crates/ra_hir_ty/src/diagnostics/expr.rs | 521 | ||||
-rw-r--r-- | crates/ra_hir_ty/src/diagnostics/match_check.rs | 2158 | ||||
-rw-r--r-- | crates/ra_hir_ty/src/diagnostics/unsafe_check.rs | 123 |
3 files changed, 2802 insertions, 0 deletions
diff --git a/crates/ra_hir_ty/src/diagnostics/expr.rs b/crates/ra_hir_ty/src/diagnostics/expr.rs new file mode 100644 index 000000000..239be779f --- /dev/null +++ b/crates/ra_hir_ty/src/diagnostics/expr.rs | |||
@@ -0,0 +1,521 @@ | |||
1 | //! FIXME: write short doc here | ||
2 | |||
3 | use std::sync::Arc; | ||
4 | |||
5 | use hir_def::{path::path, resolver::HasResolver, AdtId, DefWithBodyId}; | ||
6 | use hir_expand::diagnostics::DiagnosticSink; | ||
7 | use ra_syntax::{ast, AstPtr}; | ||
8 | use rustc_hash::FxHashSet; | ||
9 | |||
10 | use crate::{ | ||
11 | db::HirDatabase, | ||
12 | diagnostics::{ | ||
13 | match_check::{is_useful, MatchCheckCtx, Matrix, PatStack, Usefulness}, | ||
14 | MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkInTailExpr, MissingPatFields, | ||
15 | }, | ||
16 | utils::variant_data, | ||
17 | ApplicationTy, InferenceResult, Ty, TypeCtor, | ||
18 | }; | ||
19 | |||
20 | pub use hir_def::{ | ||
21 | body::{ | ||
22 | scope::{ExprScopes, ScopeEntry, ScopeId}, | ||
23 | Body, BodySourceMap, ExprPtr, ExprSource, PatPtr, PatSource, | ||
24 | }, | ||
25 | expr::{ | ||
26 | ArithOp, Array, BinaryOp, BindingAnnotation, CmpOp, Expr, ExprId, Literal, LogicOp, | ||
27 | MatchArm, Ordering, Pat, PatId, RecordFieldPat, RecordLitField, Statement, UnaryOp, | ||
28 | }, | ||
29 | src::HasSource, | ||
30 | LocalFieldId, Lookup, VariantId, | ||
31 | }; | ||
32 | |||
33 | pub(super) struct ExprValidator<'a, 'b: 'a> { | ||
34 | owner: DefWithBodyId, | ||
35 | infer: Arc<InferenceResult>, | ||
36 | sink: &'a mut DiagnosticSink<'b>, | ||
37 | } | ||
38 | |||
39 | impl<'a, 'b> ExprValidator<'a, 'b> { | ||
40 | pub(super) fn new( | ||
41 | owner: DefWithBodyId, | ||
42 | infer: Arc<InferenceResult>, | ||
43 | sink: &'a mut DiagnosticSink<'b>, | ||
44 | ) -> ExprValidator<'a, 'b> { | ||
45 | ExprValidator { owner, infer, sink } | ||
46 | } | ||
47 | |||
48 | pub(super) fn validate_body(&mut self, db: &dyn HirDatabase) { | ||
49 | let body = db.body(self.owner.into()); | ||
50 | |||
51 | for (id, expr) in body.exprs.iter() { | ||
52 | if let Some((variant_def, missed_fields, true)) = | ||
53 | record_literal_missing_fields(db, &self.infer, id, expr) | ||
54 | { | ||
55 | self.create_record_literal_missing_fields_diagnostic( | ||
56 | id, | ||
57 | db, | ||
58 | variant_def, | ||
59 | missed_fields, | ||
60 | ); | ||
61 | } | ||
62 | |||
63 | match expr { | ||
64 | Expr::Match { expr, arms } => { | ||
65 | self.validate_match(id, *expr, arms, db, self.infer.clone()); | ||
66 | } | ||
67 | Expr::Call { .. } | Expr::MethodCall { .. } => { | ||
68 | self.validate_call(db, id, expr); | ||
69 | } | ||
70 | _ => {} | ||
71 | } | ||
72 | } | ||
73 | for (id, pat) in body.pats.iter() { | ||
74 | if let Some((variant_def, missed_fields, true)) = | ||
75 | record_pattern_missing_fields(db, &self.infer, id, pat) | ||
76 | { | ||
77 | self.create_record_pattern_missing_fields_diagnostic( | ||
78 | id, | ||
79 | db, | ||
80 | variant_def, | ||
81 | missed_fields, | ||
82 | ); | ||
83 | } | ||
84 | } | ||
85 | let body_expr = &body[body.body_expr]; | ||
86 | if let Expr::Block { tail: Some(t), .. } = body_expr { | ||
87 | self.validate_results_in_tail_expr(body.body_expr, *t, db); | ||
88 | } | ||
89 | } | ||
90 | |||
91 | fn create_record_literal_missing_fields_diagnostic( | ||
92 | &mut self, | ||
93 | id: ExprId, | ||
94 | db: &dyn HirDatabase, | ||
95 | variant_def: VariantId, | ||
96 | missed_fields: Vec<LocalFieldId>, | ||
97 | ) { | ||
98 | // XXX: only look at source_map if we do have missing fields | ||
99 | let (_, source_map) = db.body_with_source_map(self.owner.into()); | ||
100 | |||
101 | if let Ok(source_ptr) = source_map.expr_syntax(id) { | ||
102 | let root = source_ptr.file_syntax(db.upcast()); | ||
103 | if let ast::Expr::RecordLit(record_lit) = &source_ptr.value.to_node(&root) { | ||
104 | if let Some(field_list) = record_lit.record_field_list() { | ||
105 | let variant_data = variant_data(db.upcast(), variant_def); | ||
106 | let missed_fields = missed_fields | ||
107 | .into_iter() | ||
108 | .map(|idx| variant_data.fields()[idx].name.clone()) | ||
109 | .collect(); | ||
110 | self.sink.push(MissingFields { | ||
111 | file: source_ptr.file_id, | ||
112 | field_list: AstPtr::new(&field_list), | ||
113 | missed_fields, | ||
114 | }) | ||
115 | } | ||
116 | } | ||
117 | } | ||
118 | } | ||
119 | |||
120 | fn create_record_pattern_missing_fields_diagnostic( | ||
121 | &mut self, | ||
122 | id: PatId, | ||
123 | db: &dyn HirDatabase, | ||
124 | variant_def: VariantId, | ||
125 | missed_fields: Vec<LocalFieldId>, | ||
126 | ) { | ||
127 | // XXX: only look at source_map if we do have missing fields | ||
128 | let (_, source_map) = db.body_with_source_map(self.owner.into()); | ||
129 | |||
130 | if let Ok(source_ptr) = source_map.pat_syntax(id) { | ||
131 | if let Some(expr) = source_ptr.value.as_ref().left() { | ||
132 | let root = source_ptr.file_syntax(db.upcast()); | ||
133 | if let ast::Pat::RecordPat(record_pat) = expr.to_node(&root) { | ||
134 | if let Some(field_list) = record_pat.record_field_pat_list() { | ||
135 | let variant_data = variant_data(db.upcast(), variant_def); | ||
136 | let missed_fields = missed_fields | ||
137 | .into_iter() | ||
138 | .map(|idx| variant_data.fields()[idx].name.clone()) | ||
139 | .collect(); | ||
140 | self.sink.push(MissingPatFields { | ||
141 | file: source_ptr.file_id, | ||
142 | field_list: AstPtr::new(&field_list), | ||
143 | missed_fields, | ||
144 | }) | ||
145 | } | ||
146 | } | ||
147 | } | ||
148 | } | ||
149 | } | ||
150 | |||
151 | fn validate_call(&mut self, db: &dyn HirDatabase, call_id: ExprId, expr: &Expr) -> Option<()> { | ||
152 | // Check that the number of arguments matches the number of parameters. | ||
153 | |||
154 | // FIXME: Due to shortcomings in the current type system implementation, only emit this | ||
155 | // diagnostic if there are no type mismatches in the containing function. | ||
156 | if self.infer.type_mismatches.iter().next().is_some() { | ||
157 | return Some(()); | ||
158 | } | ||
159 | |||
160 | let is_method_call = matches!(expr, Expr::MethodCall { .. }); | ||
161 | let (callee, args) = match expr { | ||
162 | Expr::Call { callee, args } => { | ||
163 | let callee = &self.infer.type_of_expr[*callee]; | ||
164 | let (callable, _) = callee.as_callable()?; | ||
165 | |||
166 | (callable, args.clone()) | ||
167 | } | ||
168 | Expr::MethodCall { receiver, args, .. } => { | ||
169 | let callee = self.infer.method_resolution(call_id)?; | ||
170 | let mut args = args.clone(); | ||
171 | args.insert(0, *receiver); | ||
172 | (callee.into(), args) | ||
173 | } | ||
174 | _ => return None, | ||
175 | }; | ||
176 | |||
177 | let sig = db.callable_item_signature(callee); | ||
178 | let params = sig.value.params(); | ||
179 | |||
180 | let mut param_count = params.len(); | ||
181 | let mut arg_count = args.len(); | ||
182 | |||
183 | if arg_count != param_count { | ||
184 | let (_, source_map) = db.body_with_source_map(self.owner.into()); | ||
185 | if let Ok(source_ptr) = source_map.expr_syntax(call_id) { | ||
186 | if is_method_call { | ||
187 | param_count -= 1; | ||
188 | arg_count -= 1; | ||
189 | } | ||
190 | self.sink.push(MismatchedArgCount { | ||
191 | file: source_ptr.file_id, | ||
192 | call_expr: source_ptr.value, | ||
193 | expected: param_count, | ||
194 | found: arg_count, | ||
195 | }); | ||
196 | } | ||
197 | } | ||
198 | |||
199 | None | ||
200 | } | ||
201 | |||
202 | fn validate_match( | ||
203 | &mut self, | ||
204 | id: ExprId, | ||
205 | match_expr: ExprId, | ||
206 | arms: &[MatchArm], | ||
207 | db: &dyn HirDatabase, | ||
208 | infer: Arc<InferenceResult>, | ||
209 | ) { | ||
210 | let (body, source_map): (Arc<Body>, Arc<BodySourceMap>) = | ||
211 | db.body_with_source_map(self.owner.into()); | ||
212 | |||
213 | let match_expr_ty = match infer.type_of_expr.get(match_expr) { | ||
214 | Some(ty) => ty, | ||
215 | // If we can't resolve the type of the match expression | ||
216 | // we cannot perform exhaustiveness checks. | ||
217 | None => return, | ||
218 | }; | ||
219 | |||
220 | let cx = MatchCheckCtx { match_expr, body, infer: infer.clone(), db }; | ||
221 | let pats = arms.iter().map(|arm| arm.pat); | ||
222 | |||
223 | let mut seen = Matrix::empty(); | ||
224 | for pat in pats { | ||
225 | if let Some(pat_ty) = infer.type_of_pat.get(pat) { | ||
226 | // We only include patterns whose type matches the type | ||
227 | // of the match expression. If we had a InvalidMatchArmPattern | ||
228 | // diagnostic or similar we could raise that in an else | ||
229 | // block here. | ||
230 | // | ||
231 | // When comparing the types, we also have to consider that rustc | ||
232 | // will automatically de-reference the match expression type if | ||
233 | // necessary. | ||
234 | // | ||
235 | // FIXME we should use the type checker for this. | ||
236 | if pat_ty == match_expr_ty | ||
237 | || match_expr_ty | ||
238 | .as_reference() | ||
239 | .map(|(match_expr_ty, _)| match_expr_ty == pat_ty) | ||
240 | .unwrap_or(false) | ||
241 | { | ||
242 | // If we had a NotUsefulMatchArm diagnostic, we could | ||
243 | // check the usefulness of each pattern as we added it | ||
244 | // to the matrix here. | ||
245 | let v = PatStack::from_pattern(pat); | ||
246 | seen.push(&cx, v); | ||
247 | continue; | ||
248 | } | ||
249 | } | ||
250 | |||
251 | // If we can't resolve the type of a pattern, or the pattern type doesn't | ||
252 | // fit the match expression, we skip this diagnostic. Skipping the entire | ||
253 | // diagnostic rather than just not including this match arm is preferred | ||
254 | // to avoid the chance of false positives. | ||
255 | return; | ||
256 | } | ||
257 | |||
258 | match is_useful(&cx, &seen, &PatStack::from_wild()) { | ||
259 | Ok(Usefulness::Useful) => (), | ||
260 | // if a wildcard pattern is not useful, then all patterns are covered | ||
261 | Ok(Usefulness::NotUseful) => return, | ||
262 | // this path is for unimplemented checks, so we err on the side of not | ||
263 | // reporting any errors | ||
264 | _ => return, | ||
265 | } | ||
266 | |||
267 | if let Ok(source_ptr) = source_map.expr_syntax(id) { | ||
268 | let root = source_ptr.file_syntax(db.upcast()); | ||
269 | if let ast::Expr::MatchExpr(match_expr) = &source_ptr.value.to_node(&root) { | ||
270 | if let (Some(match_expr), Some(arms)) = | ||
271 | (match_expr.expr(), match_expr.match_arm_list()) | ||
272 | { | ||
273 | self.sink.push(MissingMatchArms { | ||
274 | file: source_ptr.file_id, | ||
275 | match_expr: AstPtr::new(&match_expr), | ||
276 | arms: AstPtr::new(&arms), | ||
277 | }) | ||
278 | } | ||
279 | } | ||
280 | } | ||
281 | } | ||
282 | |||
283 | fn validate_results_in_tail_expr(&mut self, body_id: ExprId, id: ExprId, db: &dyn HirDatabase) { | ||
284 | // the mismatch will be on the whole block currently | ||
285 | let mismatch = match self.infer.type_mismatch_for_expr(body_id) { | ||
286 | Some(m) => m, | ||
287 | None => return, | ||
288 | }; | ||
289 | |||
290 | let core_result_path = path![core::result::Result]; | ||
291 | |||
292 | let resolver = self.owner.resolver(db.upcast()); | ||
293 | let core_result_enum = match resolver.resolve_known_enum(db.upcast(), &core_result_path) { | ||
294 | Some(it) => it, | ||
295 | _ => return, | ||
296 | }; | ||
297 | |||
298 | let core_result_ctor = TypeCtor::Adt(AdtId::EnumId(core_result_enum)); | ||
299 | let params = match &mismatch.expected { | ||
300 | Ty::Apply(ApplicationTy { ctor, parameters }) if ctor == &core_result_ctor => { | ||
301 | parameters | ||
302 | } | ||
303 | _ => return, | ||
304 | }; | ||
305 | |||
306 | if params.len() == 2 && params[0] == mismatch.actual { | ||
307 | let (_, source_map) = db.body_with_source_map(self.owner.into()); | ||
308 | |||
309 | if let Ok(source_ptr) = source_map.expr_syntax(id) { | ||
310 | self.sink | ||
311 | .push(MissingOkInTailExpr { file: source_ptr.file_id, expr: source_ptr.value }); | ||
312 | } | ||
313 | } | ||
314 | } | ||
315 | } | ||
316 | |||
317 | pub fn record_literal_missing_fields( | ||
318 | db: &dyn HirDatabase, | ||
319 | infer: &InferenceResult, | ||
320 | id: ExprId, | ||
321 | expr: &Expr, | ||
322 | ) -> Option<(VariantId, Vec<LocalFieldId>, /*exhaustive*/ bool)> { | ||
323 | let (fields, exhausitve) = match expr { | ||
324 | Expr::RecordLit { path: _, fields, spread } => (fields, spread.is_none()), | ||
325 | _ => return None, | ||
326 | }; | ||
327 | |||
328 | let variant_def = infer.variant_resolution_for_expr(id)?; | ||
329 | if let VariantId::UnionId(_) = variant_def { | ||
330 | return None; | ||
331 | } | ||
332 | |||
333 | let variant_data = variant_data(db.upcast(), variant_def); | ||
334 | |||
335 | let specified_fields: FxHashSet<_> = fields.iter().map(|f| &f.name).collect(); | ||
336 | let missed_fields: Vec<LocalFieldId> = variant_data | ||
337 | .fields() | ||
338 | .iter() | ||
339 | .filter_map(|(f, d)| if specified_fields.contains(&d.name) { None } else { Some(f) }) | ||
340 | .collect(); | ||
341 | if missed_fields.is_empty() { | ||
342 | return None; | ||
343 | } | ||
344 | Some((variant_def, missed_fields, exhausitve)) | ||
345 | } | ||
346 | |||
347 | pub fn record_pattern_missing_fields( | ||
348 | db: &dyn HirDatabase, | ||
349 | infer: &InferenceResult, | ||
350 | id: PatId, | ||
351 | pat: &Pat, | ||
352 | ) -> Option<(VariantId, Vec<LocalFieldId>, /*exhaustive*/ bool)> { | ||
353 | let (fields, exhaustive) = match pat { | ||
354 | Pat::Record { path: _, args, ellipsis } => (args, !ellipsis), | ||
355 | _ => return None, | ||
356 | }; | ||
357 | |||
358 | let variant_def = infer.variant_resolution_for_pat(id)?; | ||
359 | if let VariantId::UnionId(_) = variant_def { | ||
360 | return None; | ||
361 | } | ||
362 | |||
363 | let variant_data = variant_data(db.upcast(), variant_def); | ||
364 | |||
365 | let specified_fields: FxHashSet<_> = fields.iter().map(|f| &f.name).collect(); | ||
366 | let missed_fields: Vec<LocalFieldId> = variant_data | ||
367 | .fields() | ||
368 | .iter() | ||
369 | .filter_map(|(f, d)| if specified_fields.contains(&d.name) { None } else { Some(f) }) | ||
370 | .collect(); | ||
371 | if missed_fields.is_empty() { | ||
372 | return None; | ||
373 | } | ||
374 | Some((variant_def, missed_fields, exhaustive)) | ||
375 | } | ||
376 | |||
377 | #[cfg(test)] | ||
378 | mod tests { | ||
379 | use expect::{expect, Expect}; | ||
380 | use ra_db::fixture::WithFixture; | ||
381 | |||
382 | use crate::{diagnostics::MismatchedArgCount, test_db::TestDB}; | ||
383 | |||
384 | fn check_diagnostic(ra_fixture: &str, expect: Expect) { | ||
385 | let msg = TestDB::with_single_file(ra_fixture).0.diagnostic::<MismatchedArgCount>().0; | ||
386 | expect.assert_eq(&msg); | ||
387 | } | ||
388 | |||
389 | fn check_no_diagnostic(ra_fixture: &str) { | ||
390 | let (s, diagnostic_count) = | ||
391 | TestDB::with_single_file(ra_fixture).0.diagnostic::<MismatchedArgCount>(); | ||
392 | |||
393 | assert_eq!(0, diagnostic_count, "expected no diagnostic, found one: {}", s); | ||
394 | } | ||
395 | |||
396 | #[test] | ||
397 | fn simple_free_fn_zero() { | ||
398 | check_diagnostic( | ||
399 | r" | ||
400 | fn zero() {} | ||
401 | fn f() { zero(1); } | ||
402 | ", | ||
403 | expect![["\"zero(1)\": Expected 0 arguments, found 1\n"]], | ||
404 | ); | ||
405 | |||
406 | check_no_diagnostic( | ||
407 | r" | ||
408 | fn zero() {} | ||
409 | fn f() { zero(); } | ||
410 | ", | ||
411 | ); | ||
412 | } | ||
413 | |||
414 | #[test] | ||
415 | fn simple_free_fn_one() { | ||
416 | check_diagnostic( | ||
417 | r" | ||
418 | fn one(arg: u8) {} | ||
419 | fn f() { one(); } | ||
420 | ", | ||
421 | expect![["\"one()\": Expected 1 argument, found 0\n"]], | ||
422 | ); | ||
423 | |||
424 | check_no_diagnostic( | ||
425 | r" | ||
426 | fn one(arg: u8) {} | ||
427 | fn f() { one(1); } | ||
428 | ", | ||
429 | ); | ||
430 | } | ||
431 | |||
432 | #[test] | ||
433 | fn method_as_fn() { | ||
434 | check_diagnostic( | ||
435 | r" | ||
436 | struct S; | ||
437 | impl S { | ||
438 | fn method(&self) {} | ||
439 | } | ||
440 | |||
441 | fn f() { | ||
442 | S::method(); | ||
443 | } | ||
444 | ", | ||
445 | expect![["\"S::method()\": Expected 1 argument, found 0\n"]], | ||
446 | ); | ||
447 | |||
448 | check_no_diagnostic( | ||
449 | r" | ||
450 | struct S; | ||
451 | impl S { | ||
452 | fn method(&self) {} | ||
453 | } | ||
454 | |||
455 | fn f() { | ||
456 | S::method(&S); | ||
457 | S.method(); | ||
458 | } | ||
459 | ", | ||
460 | ); | ||
461 | } | ||
462 | |||
463 | #[test] | ||
464 | fn method_with_arg() { | ||
465 | check_diagnostic( | ||
466 | r" | ||
467 | struct S; | ||
468 | impl S { | ||
469 | fn method(&self, arg: u8) {} | ||
470 | } | ||
471 | |||
472 | fn f() { | ||
473 | S.method(); | ||
474 | } | ||
475 | ", | ||
476 | expect![["\"S.method()\": Expected 1 argument, found 0\n"]], | ||
477 | ); | ||
478 | |||
479 | check_no_diagnostic( | ||
480 | r" | ||
481 | struct S; | ||
482 | impl S { | ||
483 | fn method(&self, arg: u8) {} | ||
484 | } | ||
485 | |||
486 | fn f() { | ||
487 | S::method(&S, 0); | ||
488 | S.method(1); | ||
489 | } | ||
490 | ", | ||
491 | ); | ||
492 | } | ||
493 | |||
494 | #[test] | ||
495 | fn tuple_struct() { | ||
496 | check_diagnostic( | ||
497 | r" | ||
498 | struct Tup(u8, u16); | ||
499 | fn f() { | ||
500 | Tup(0); | ||
501 | } | ||
502 | ", | ||
503 | expect![["\"Tup(0)\": Expected 2 arguments, found 1\n"]], | ||
504 | ) | ||
505 | } | ||
506 | |||
507 | #[test] | ||
508 | fn enum_variant() { | ||
509 | check_diagnostic( | ||
510 | r" | ||
511 | enum En { | ||
512 | Variant(u8, u16), | ||
513 | } | ||
514 | fn f() { | ||
515 | En::Variant(0); | ||
516 | } | ||
517 | ", | ||
518 | expect![["\"En::Variant(0)\": Expected 2 arguments, found 1\n"]], | ||
519 | ) | ||
520 | } | ||
521 | } | ||
diff --git a/crates/ra_hir_ty/src/diagnostics/match_check.rs b/crates/ra_hir_ty/src/diagnostics/match_check.rs new file mode 100644 index 000000000..722c0e9ee --- /dev/null +++ b/crates/ra_hir_ty/src/diagnostics/match_check.rs | |||
@@ -0,0 +1,2158 @@ | |||
1 | //! This module implements match statement exhaustiveness checking and usefulness checking | ||
2 | //! for match arms. | ||
3 | //! | ||
4 | //! It is modeled on the rustc module `librustc_mir_build::hair::pattern::_match`, which | ||
5 | //! contains very detailed documentation about the algorithms used here. I've duplicated | ||
6 | //! most of that documentation below. | ||
7 | //! | ||
8 | //! This file includes the logic for exhaustiveness and usefulness checking for | ||
9 | //! pattern-matching. Specifically, given a list of patterns for a type, we can | ||
10 | //! tell whether: | ||
11 | //! - (a) the patterns cover every possible constructor for the type (exhaustiveness). | ||
12 | //! - (b) each pattern is necessary (usefulness). | ||
13 | //! | ||
14 | //! The algorithm implemented here is a modified version of the one described in | ||
15 | //! <http://moscova.inria.fr/~maranget/papers/warn/index.html>. | ||
16 | //! However, to save future implementors from reading the original paper, we | ||
17 | //! summarise the algorithm here to hopefully save time and be a little clearer | ||
18 | //! (without being so rigorous). | ||
19 | //! | ||
20 | //! The core of the algorithm revolves about a "usefulness" check. In particular, we | ||
21 | //! are trying to compute a predicate `U(P, p)` where `P` is a list of patterns (we refer to this as | ||
22 | //! a matrix). `U(P, p)` represents whether, given an existing list of patterns | ||
23 | //! `P_1 ..= P_m`, adding a new pattern `p` will be "useful" (that is, cover previously- | ||
24 | //! uncovered values of the type). | ||
25 | //! | ||
26 | //! If we have this predicate, then we can easily compute both exhaustiveness of an | ||
27 | //! entire set of patterns and the individual usefulness of each one. | ||
28 | //! (a) the set of patterns is exhaustive iff `U(P, _)` is false (i.e., adding a wildcard | ||
29 | //! match doesn't increase the number of values we're matching) | ||
30 | //! (b) a pattern `P_i` is not useful if `U(P[0..=(i-1), P_i)` is false (i.e., adding a | ||
31 | //! pattern to those that have come before it doesn't increase the number of values | ||
32 | //! we're matching). | ||
33 | //! | ||
34 | //! During the course of the algorithm, the rows of the matrix won't just be individual patterns, | ||
35 | //! but rather partially-deconstructed patterns in the form of a list of patterns. The paper | ||
36 | //! calls those pattern-vectors, and we will call them pattern-stacks. The same holds for the | ||
37 | //! new pattern `p`. | ||
38 | //! | ||
39 | //! For example, say we have the following: | ||
40 | //! | ||
41 | //! ```ignore | ||
42 | //! // x: (Option<bool>, Result<()>) | ||
43 | //! match x { | ||
44 | //! (Some(true), _) => {} | ||
45 | //! (None, Err(())) => {} | ||
46 | //! (None, Err(_)) => {} | ||
47 | //! } | ||
48 | //! ``` | ||
49 | //! | ||
50 | //! Here, the matrix `P` starts as: | ||
51 | //! | ||
52 | //! ```text | ||
53 | //! [ | ||
54 | //! [(Some(true), _)], | ||
55 | //! [(None, Err(()))], | ||
56 | //! [(None, Err(_))], | ||
57 | //! ] | ||
58 | //! ``` | ||
59 | //! | ||
60 | //! We can tell it's not exhaustive, because `U(P, _)` is true (we're not covering | ||
61 | //! `[(Some(false), _)]`, for instance). In addition, row 3 is not useful, because | ||
62 | //! all the values it covers are already covered by row 2. | ||
63 | //! | ||
64 | //! A list of patterns can be thought of as a stack, because we are mainly interested in the top of | ||
65 | //! the stack at any given point, and we can pop or apply constructors to get new pattern-stacks. | ||
66 | //! To match the paper, the top of the stack is at the beginning / on the left. | ||
67 | //! | ||
68 | //! There are two important operations on pattern-stacks necessary to understand the algorithm: | ||
69 | //! | ||
70 | //! 1. We can pop a given constructor off the top of a stack. This operation is called | ||
71 | //! `specialize`, and is denoted `S(c, p)` where `c` is a constructor (like `Some` or | ||
72 | //! `None`) and `p` a pattern-stack. | ||
73 | //! If the pattern on top of the stack can cover `c`, this removes the constructor and | ||
74 | //! pushes its arguments onto the stack. It also expands OR-patterns into distinct patterns. | ||
75 | //! Otherwise the pattern-stack is discarded. | ||
76 | //! This essentially filters those pattern-stacks whose top covers the constructor `c` and | ||
77 | //! discards the others. | ||
78 | //! | ||
79 | //! For example, the first pattern above initially gives a stack `[(Some(true), _)]`. If we | ||
80 | //! pop the tuple constructor, we are left with `[Some(true), _]`, and if we then pop the | ||
81 | //! `Some` constructor we get `[true, _]`. If we had popped `None` instead, we would get | ||
82 | //! nothing back. | ||
83 | //! | ||
84 | //! This returns zero or more new pattern-stacks, as follows. We look at the pattern `p_1` | ||
85 | //! on top of the stack, and we have four cases: | ||
86 | //! | ||
87 | //! * 1.1. `p_1 = c(r_1, .., r_a)`, i.e. the top of the stack has constructor `c`. We push onto | ||
88 | //! the stack the arguments of this constructor, and return the result: | ||
89 | //! | ||
90 | //! r_1, .., r_a, p_2, .., p_n | ||
91 | //! | ||
92 | //! * 1.2. `p_1 = c'(r_1, .., r_a')` where `c ≠c'`. We discard the current stack and return | ||
93 | //! nothing. | ||
94 | //! * 1.3. `p_1 = _`. We push onto the stack as many wildcards as the constructor `c` has | ||
95 | //! arguments (its arity), and return the resulting stack: | ||
96 | //! | ||
97 | //! _, .., _, p_2, .., p_n | ||
98 | //! | ||
99 | //! * 1.4. `p_1 = r_1 | r_2`. We expand the OR-pattern and then recurse on each resulting stack: | ||
100 | //! | ||
101 | //! S(c, (r_1, p_2, .., p_n)) | ||
102 | //! S(c, (r_2, p_2, .., p_n)) | ||
103 | //! | ||
104 | //! 2. We can pop a wildcard off the top of the stack. This is called `D(p)`, where `p` is | ||
105 | //! a pattern-stack. | ||
106 | //! This is used when we know there are missing constructor cases, but there might be | ||
107 | //! existing wildcard patterns, so to check the usefulness of the matrix, we have to check | ||
108 | //! all its *other* components. | ||
109 | //! | ||
110 | //! It is computed as follows. We look at the pattern `p_1` on top of the stack, | ||
111 | //! and we have three cases: | ||
112 | //! * 1.1. `p_1 = c(r_1, .., r_a)`. We discard the current stack and return nothing. | ||
113 | //! * 1.2. `p_1 = _`. We return the rest of the stack: | ||
114 | //! | ||
115 | //! p_2, .., p_n | ||
116 | //! | ||
117 | //! * 1.3. `p_1 = r_1 | r_2`. We expand the OR-pattern and then recurse on each resulting stack: | ||
118 | //! | ||
119 | //! D((r_1, p_2, .., p_n)) | ||
120 | //! D((r_2, p_2, .., p_n)) | ||
121 | //! | ||
122 | //! Note that the OR-patterns are not always used directly in Rust, but are used to derive the | ||
123 | //! exhaustive integer matching rules, so they're written here for posterity. | ||
124 | //! | ||
125 | //! Both those operations extend straightforwardly to a list or pattern-stacks, i.e. a matrix, by | ||
126 | //! working row-by-row. Popping a constructor ends up keeping only the matrix rows that start with | ||
127 | //! the given constructor, and popping a wildcard keeps those rows that start with a wildcard. | ||
128 | //! | ||
129 | //! | ||
130 | //! The algorithm for computing `U` | ||
131 | //! ------------------------------- | ||
132 | //! The algorithm is inductive (on the number of columns: i.e., components of tuple patterns). | ||
133 | //! That means we're going to check the components from left-to-right, so the algorithm | ||
134 | //! operates principally on the first component of the matrix and new pattern-stack `p`. | ||
135 | //! This algorithm is realised in the `is_useful` function. | ||
136 | //! | ||
137 | //! Base case (`n = 0`, i.e., an empty tuple pattern): | ||
138 | //! - If `P` already contains an empty pattern (i.e., if the number of patterns `m > 0`), then | ||
139 | //! `U(P, p)` is false. | ||
140 | //! - Otherwise, `P` must be empty, so `U(P, p)` is true. | ||
141 | //! | ||
142 | //! Inductive step (`n > 0`, i.e., whether there's at least one column [which may then be expanded | ||
143 | //! into further columns later]). We're going to match on the top of the new pattern-stack, `p_1`: | ||
144 | //! | ||
145 | //! - If `p_1 == c(r_1, .., r_a)`, i.e. we have a constructor pattern. | ||
146 | //! Then, the usefulness of `p_1` can be reduced to whether it is useful when | ||
147 | //! we ignore all the patterns in the first column of `P` that involve other constructors. | ||
148 | //! This is where `S(c, P)` comes in: | ||
149 | //! | ||
150 | //! ```text | ||
151 | //! U(P, p) := U(S(c, P), S(c, p)) | ||
152 | //! ``` | ||
153 | //! | ||
154 | //! This special case is handled in `is_useful_specialized`. | ||
155 | //! | ||
156 | //! For example, if `P` is: | ||
157 | //! | ||
158 | //! ```text | ||
159 | //! [ | ||
160 | //! [Some(true), _], | ||
161 | //! [None, 0], | ||
162 | //! ] | ||
163 | //! ``` | ||
164 | //! | ||
165 | //! and `p` is `[Some(false), 0]`, then we don't care about row 2 since we know `p` only | ||
166 | //! matches values that row 2 doesn't. For row 1 however, we need to dig into the | ||
167 | //! arguments of `Some` to know whether some new value is covered. So we compute | ||
168 | //! `U([[true, _]], [false, 0])`. | ||
169 | //! | ||
170 | //! - If `p_1 == _`, then we look at the list of constructors that appear in the first component of | ||
171 | //! the rows of `P`: | ||
172 | //! - If there are some constructors that aren't present, then we might think that the | ||
173 | //! wildcard `_` is useful, since it covers those constructors that weren't covered | ||
174 | //! before. | ||
175 | //! That's almost correct, but only works if there were no wildcards in those first | ||
176 | //! components. So we need to check that `p` is useful with respect to the rows that | ||
177 | //! start with a wildcard, if there are any. This is where `D` comes in: | ||
178 | //! `U(P, p) := U(D(P), D(p))` | ||
179 | //! | ||
180 | //! For example, if `P` is: | ||
181 | //! ```text | ||
182 | //! [ | ||
183 | //! [_, true, _], | ||
184 | //! [None, false, 1], | ||
185 | //! ] | ||
186 | //! ``` | ||
187 | //! and `p` is `[_, false, _]`, the `Some` constructor doesn't appear in `P`. So if we | ||
188 | //! only had row 2, we'd know that `p` is useful. However row 1 starts with a | ||
189 | //! wildcard, so we need to check whether `U([[true, _]], [false, 1])`. | ||
190 | //! | ||
191 | //! - Otherwise, all possible constructors (for the relevant type) are present. In this | ||
192 | //! case we must check whether the wildcard pattern covers any unmatched value. For | ||
193 | //! that, we can think of the `_` pattern as a big OR-pattern that covers all | ||
194 | //! possible constructors. For `Option`, that would mean `_ = None | Some(_)` for | ||
195 | //! example. The wildcard pattern is useful in this case if it is useful when | ||
196 | //! specialized to one of the possible constructors. So we compute: | ||
197 | //! `U(P, p) := ∃(k ϵ constructors) U(S(k, P), S(k, p))` | ||
198 | //! | ||
199 | //! For example, if `P` is: | ||
200 | //! ```text | ||
201 | //! [ | ||
202 | //! [Some(true), _], | ||
203 | //! [None, false], | ||
204 | //! ] | ||
205 | //! ``` | ||
206 | //! and `p` is `[_, false]`, both `None` and `Some` constructors appear in the first | ||
207 | //! components of `P`. We will therefore try popping both constructors in turn: we | ||
208 | //! compute `U([[true, _]], [_, false])` for the `Some` constructor, and `U([[false]], | ||
209 | //! [false])` for the `None` constructor. The first case returns true, so we know that | ||
210 | //! `p` is useful for `P`. Indeed, it matches `[Some(false), _]` that wasn't matched | ||
211 | //! before. | ||
212 | //! | ||
213 | //! - If `p_1 == r_1 | r_2`, then the usefulness depends on each `r_i` separately: | ||
214 | //! | ||
215 | //! ```text | ||
216 | //! U(P, p) := U(P, (r_1, p_2, .., p_n)) | ||
217 | //! || U(P, (r_2, p_2, .., p_n)) | ||
218 | //! ``` | ||
219 | use std::sync::Arc; | ||
220 | |||
221 | use hir_def::{ | ||
222 | adt::VariantData, | ||
223 | body::Body, | ||
224 | expr::{Expr, Literal, Pat, PatId}, | ||
225 | AdtId, EnumVariantId, VariantId, | ||
226 | }; | ||
227 | use ra_arena::Idx; | ||
228 | use smallvec::{smallvec, SmallVec}; | ||
229 | |||
230 | use crate::{db::HirDatabase, ApplicationTy, InferenceResult, Ty, TypeCtor}; | ||
231 | |||
232 | #[derive(Debug, Clone, Copy)] | ||
233 | /// Either a pattern from the source code being analyzed, represented as | ||
234 | /// as `PatId`, or a `Wild` pattern which is created as an intermediate | ||
235 | /// step in the match checking algorithm and thus is not backed by a | ||
236 | /// real `PatId`. | ||
237 | /// | ||
238 | /// Note that it is totally valid for the `PatId` variant to contain | ||
239 | /// a `PatId` which resolves to a `Wild` pattern, if that wild pattern | ||
240 | /// exists in the source code being analyzed. | ||
241 | enum PatIdOrWild { | ||
242 | PatId(PatId), | ||
243 | Wild, | ||
244 | } | ||
245 | |||
246 | impl PatIdOrWild { | ||
247 | fn as_pat(self, cx: &MatchCheckCtx) -> Pat { | ||
248 | match self { | ||
249 | PatIdOrWild::PatId(id) => cx.body.pats[id].clone(), | ||
250 | PatIdOrWild::Wild => Pat::Wild, | ||
251 | } | ||
252 | } | ||
253 | |||
254 | fn as_id(self) -> Option<PatId> { | ||
255 | match self { | ||
256 | PatIdOrWild::PatId(id) => Some(id), | ||
257 | PatIdOrWild::Wild => None, | ||
258 | } | ||
259 | } | ||
260 | } | ||
261 | |||
262 | impl From<PatId> for PatIdOrWild { | ||
263 | fn from(pat_id: PatId) -> Self { | ||
264 | Self::PatId(pat_id) | ||
265 | } | ||
266 | } | ||
267 | |||
268 | impl From<&PatId> for PatIdOrWild { | ||
269 | fn from(pat_id: &PatId) -> Self { | ||
270 | Self::PatId(*pat_id) | ||
271 | } | ||
272 | } | ||
273 | |||
274 | #[derive(Debug, Clone, Copy, PartialEq)] | ||
275 | pub enum MatchCheckErr { | ||
276 | NotImplemented, | ||
277 | MalformedMatchArm, | ||
278 | /// Used when type inference cannot resolve the type of | ||
279 | /// a pattern or expression. | ||
280 | Unknown, | ||
281 | } | ||
282 | |||
283 | /// The return type of `is_useful` is either an indication of usefulness | ||
284 | /// of the match arm, or an error in the case the match statement | ||
285 | /// is made up of types for which exhaustiveness checking is currently | ||
286 | /// not completely implemented. | ||
287 | /// | ||
288 | /// The `std::result::Result` type is used here rather than a custom enum | ||
289 | /// to allow the use of `?`. | ||
290 | pub type MatchCheckResult<T> = Result<T, MatchCheckErr>; | ||
291 | |||
292 | #[derive(Debug)] | ||
293 | /// A row in a Matrix. | ||
294 | /// | ||
295 | /// This type is modeled from the struct of the same name in `rustc`. | ||
296 | pub(crate) struct PatStack(PatStackInner); | ||
297 | type PatStackInner = SmallVec<[PatIdOrWild; 2]>; | ||
298 | |||
299 | impl PatStack { | ||
300 | pub(crate) fn from_pattern(pat_id: PatId) -> PatStack { | ||
301 | Self(smallvec!(pat_id.into())) | ||
302 | } | ||
303 | |||
304 | pub(crate) fn from_wild() -> PatStack { | ||
305 | Self(smallvec!(PatIdOrWild::Wild)) | ||
306 | } | ||
307 | |||
308 | fn from_slice(slice: &[PatIdOrWild]) -> PatStack { | ||
309 | Self(SmallVec::from_slice(slice)) | ||
310 | } | ||
311 | |||
312 | fn from_vec(v: PatStackInner) -> PatStack { | ||
313 | Self(v) | ||
314 | } | ||
315 | |||
316 | fn get_head(&self) -> Option<PatIdOrWild> { | ||
317 | self.0.first().copied() | ||
318 | } | ||
319 | |||
320 | fn tail(&self) -> &[PatIdOrWild] { | ||
321 | self.0.get(1..).unwrap_or(&[]) | ||
322 | } | ||
323 | |||
324 | fn to_tail(&self) -> PatStack { | ||
325 | Self::from_slice(self.tail()) | ||
326 | } | ||
327 | |||
328 | fn replace_head_with<I, T>(&self, pats: I) -> PatStack | ||
329 | where | ||
330 | I: Iterator<Item = T>, | ||
331 | T: Into<PatIdOrWild>, | ||
332 | { | ||
333 | let mut patterns: PatStackInner = smallvec![]; | ||
334 | for pat in pats { | ||
335 | patterns.push(pat.into()); | ||
336 | } | ||
337 | for pat in &self.0[1..] { | ||
338 | patterns.push(*pat); | ||
339 | } | ||
340 | PatStack::from_vec(patterns) | ||
341 | } | ||
342 | |||
343 | /// Computes `D(self)`. | ||
344 | /// | ||
345 | /// See the module docs and the associated documentation in rustc for details. | ||
346 | fn specialize_wildcard(&self, cx: &MatchCheckCtx) -> Option<PatStack> { | ||
347 | if matches!(self.get_head()?.as_pat(cx), Pat::Wild) { | ||
348 | Some(self.to_tail()) | ||
349 | } else { | ||
350 | None | ||
351 | } | ||
352 | } | ||
353 | |||
354 | /// Computes `S(constructor, self)`. | ||
355 | /// | ||
356 | /// See the module docs and the associated documentation in rustc for details. | ||
357 | fn specialize_constructor( | ||
358 | &self, | ||
359 | cx: &MatchCheckCtx, | ||
360 | constructor: &Constructor, | ||
361 | ) -> MatchCheckResult<Option<PatStack>> { | ||
362 | let head = match self.get_head() { | ||
363 | Some(head) => head, | ||
364 | None => return Ok(None), | ||
365 | }; | ||
366 | |||
367 | let head_pat = head.as_pat(cx); | ||
368 | let result = match (head_pat, constructor) { | ||
369 | (Pat::Tuple { args: ref pat_ids, ellipsis }, Constructor::Tuple { arity: _ }) => { | ||
370 | if ellipsis.is_some() { | ||
371 | // If there are ellipsis here, we should add the correct number of | ||
372 | // Pat::Wild patterns to `pat_ids`. We should be able to use the | ||
373 | // constructors arity for this, but at the time of writing we aren't | ||
374 | // correctly calculating this arity when ellipsis are present. | ||
375 | return Err(MatchCheckErr::NotImplemented); | ||
376 | } | ||
377 | |||
378 | Some(self.replace_head_with(pat_ids.iter())) | ||
379 | } | ||
380 | (Pat::Lit(lit_expr), Constructor::Bool(constructor_val)) => { | ||
381 | match cx.body.exprs[lit_expr] { | ||
382 | Expr::Literal(Literal::Bool(pat_val)) if *constructor_val == pat_val => { | ||
383 | Some(self.to_tail()) | ||
384 | } | ||
385 | // it was a bool but the value doesn't match | ||
386 | Expr::Literal(Literal::Bool(_)) => None, | ||
387 | // perhaps this is actually unreachable given we have | ||
388 | // already checked that these match arms have the appropriate type? | ||
389 | _ => return Err(MatchCheckErr::NotImplemented), | ||
390 | } | ||
391 | } | ||
392 | (Pat::Wild, constructor) => Some(self.expand_wildcard(cx, constructor)?), | ||
393 | (Pat::Path(_), Constructor::Enum(constructor)) => { | ||
394 | // unit enum variants become `Pat::Path` | ||
395 | let pat_id = head.as_id().expect("we know this isn't a wild"); | ||
396 | if !enum_variant_matches(cx, pat_id, *constructor) { | ||
397 | None | ||
398 | } else { | ||
399 | Some(self.to_tail()) | ||
400 | } | ||
401 | } | ||
402 | ( | ||
403 | Pat::TupleStruct { args: ref pat_ids, ellipsis, .. }, | ||
404 | Constructor::Enum(enum_constructor), | ||
405 | ) => { | ||
406 | let pat_id = head.as_id().expect("we know this isn't a wild"); | ||
407 | if !enum_variant_matches(cx, pat_id, *enum_constructor) { | ||
408 | None | ||
409 | } else { | ||
410 | let constructor_arity = constructor.arity(cx)?; | ||
411 | if let Some(ellipsis_position) = ellipsis { | ||
412 | // If there are ellipsis in the pattern, the ellipsis must take the place | ||
413 | // of at least one sub-pattern, so `pat_ids` should be smaller than the | ||
414 | // constructor arity. | ||
415 | if pat_ids.len() < constructor_arity { | ||
416 | let mut new_patterns: Vec<PatIdOrWild> = vec![]; | ||
417 | |||
418 | for pat_id in &pat_ids[0..ellipsis_position] { | ||
419 | new_patterns.push((*pat_id).into()); | ||
420 | } | ||
421 | |||
422 | for _ in 0..(constructor_arity - pat_ids.len()) { | ||
423 | new_patterns.push(PatIdOrWild::Wild); | ||
424 | } | ||
425 | |||
426 | for pat_id in &pat_ids[ellipsis_position..pat_ids.len()] { | ||
427 | new_patterns.push((*pat_id).into()); | ||
428 | } | ||
429 | |||
430 | Some(self.replace_head_with(new_patterns.into_iter())) | ||
431 | } else { | ||
432 | return Err(MatchCheckErr::MalformedMatchArm); | ||
433 | } | ||
434 | } else { | ||
435 | // If there is no ellipsis in the tuple pattern, the number | ||
436 | // of patterns must equal the constructor arity. | ||
437 | if pat_ids.len() == constructor_arity { | ||
438 | Some(self.replace_head_with(pat_ids.into_iter())) | ||
439 | } else { | ||
440 | return Err(MatchCheckErr::MalformedMatchArm); | ||
441 | } | ||
442 | } | ||
443 | } | ||
444 | } | ||
445 | (Pat::Record { args: ref arg_patterns, .. }, Constructor::Enum(e)) => { | ||
446 | let pat_id = head.as_id().expect("we know this isn't a wild"); | ||
447 | if !enum_variant_matches(cx, pat_id, *e) { | ||
448 | None | ||
449 | } else { | ||
450 | match cx.db.enum_data(e.parent).variants[e.local_id].variant_data.as_ref() { | ||
451 | VariantData::Record(struct_field_arena) => { | ||
452 | // Here we treat any missing fields in the record as the wild pattern, as | ||
453 | // if the record has ellipsis. We want to do this here even if the | ||
454 | // record does not contain ellipsis, because it allows us to continue | ||
455 | // enforcing exhaustiveness for the rest of the match statement. | ||
456 | // | ||
457 | // Creating the diagnostic for the missing field in the pattern | ||
458 | // should be done in a different diagnostic. | ||
459 | let patterns = struct_field_arena.iter().map(|(_, struct_field)| { | ||
460 | arg_patterns | ||
461 | .iter() | ||
462 | .find(|pat| pat.name == struct_field.name) | ||
463 | .map(|pat| PatIdOrWild::from(pat.pat)) | ||
464 | .unwrap_or(PatIdOrWild::Wild) | ||
465 | }); | ||
466 | |||
467 | Some(self.replace_head_with(patterns)) | ||
468 | } | ||
469 | _ => return Err(MatchCheckErr::Unknown), | ||
470 | } | ||
471 | } | ||
472 | } | ||
473 | (Pat::Or(_), _) => return Err(MatchCheckErr::NotImplemented), | ||
474 | (_, _) => return Err(MatchCheckErr::NotImplemented), | ||
475 | }; | ||
476 | |||
477 | Ok(result) | ||
478 | } | ||
479 | |||
480 | /// A special case of `specialize_constructor` where the head of the pattern stack | ||
481 | /// is a Wild pattern. | ||
482 | /// | ||
483 | /// Replaces the Wild pattern at the head of the pattern stack with N Wild patterns | ||
484 | /// (N >= 0), where N is the arity of the given constructor. | ||
485 | fn expand_wildcard( | ||
486 | &self, | ||
487 | cx: &MatchCheckCtx, | ||
488 | constructor: &Constructor, | ||
489 | ) -> MatchCheckResult<PatStack> { | ||
490 | assert_eq!( | ||
491 | Pat::Wild, | ||
492 | self.get_head().expect("expand_wildcard called on empty PatStack").as_pat(cx), | ||
493 | "expand_wildcard must only be called on PatStack with wild at head", | ||
494 | ); | ||
495 | |||
496 | let mut patterns: PatStackInner = smallvec![]; | ||
497 | |||
498 | for _ in 0..constructor.arity(cx)? { | ||
499 | patterns.push(PatIdOrWild::Wild); | ||
500 | } | ||
501 | |||
502 | for pat in &self.0[1..] { | ||
503 | patterns.push(*pat); | ||
504 | } | ||
505 | |||
506 | Ok(PatStack::from_vec(patterns)) | ||
507 | } | ||
508 | } | ||
509 | |||
510 | /// A collection of PatStack. | ||
511 | /// | ||
512 | /// This type is modeled from the struct of the same name in `rustc`. | ||
513 | pub(crate) struct Matrix(Vec<PatStack>); | ||
514 | |||
515 | impl Matrix { | ||
516 | pub(crate) fn empty() -> Self { | ||
517 | Self(vec![]) | ||
518 | } | ||
519 | |||
520 | pub(crate) fn push(&mut self, cx: &MatchCheckCtx, row: PatStack) { | ||
521 | if let Some(Pat::Or(pat_ids)) = row.get_head().map(|pat_id| pat_id.as_pat(cx)) { | ||
522 | // Or patterns are expanded here | ||
523 | for pat_id in pat_ids { | ||
524 | self.0.push(PatStack::from_pattern(pat_id)); | ||
525 | } | ||
526 | } else { | ||
527 | self.0.push(row); | ||
528 | } | ||
529 | } | ||
530 | |||
531 | fn is_empty(&self) -> bool { | ||
532 | self.0.is_empty() | ||
533 | } | ||
534 | |||
535 | fn heads(&self) -> Vec<PatIdOrWild> { | ||
536 | self.0.iter().flat_map(|p| p.get_head()).collect() | ||
537 | } | ||
538 | |||
539 | /// Computes `D(self)` for each contained PatStack. | ||
540 | /// | ||
541 | /// See the module docs and the associated documentation in rustc for details. | ||
542 | fn specialize_wildcard(&self, cx: &MatchCheckCtx) -> Self { | ||
543 | Self::collect(cx, self.0.iter().filter_map(|r| r.specialize_wildcard(cx))) | ||
544 | } | ||
545 | |||
546 | /// Computes `S(constructor, self)` for each contained PatStack. | ||
547 | /// | ||
548 | /// See the module docs and the associated documentation in rustc for details. | ||
549 | fn specialize_constructor( | ||
550 | &self, | ||
551 | cx: &MatchCheckCtx, | ||
552 | constructor: &Constructor, | ||
553 | ) -> MatchCheckResult<Self> { | ||
554 | let mut new_matrix = Matrix::empty(); | ||
555 | for pat in &self.0 { | ||
556 | if let Some(pat) = pat.specialize_constructor(cx, constructor)? { | ||
557 | new_matrix.push(cx, pat); | ||
558 | } | ||
559 | } | ||
560 | |||
561 | Ok(new_matrix) | ||
562 | } | ||
563 | |||
564 | fn collect<T: IntoIterator<Item = PatStack>>(cx: &MatchCheckCtx, iter: T) -> Self { | ||
565 | let mut matrix = Matrix::empty(); | ||
566 | |||
567 | for pat in iter { | ||
568 | // using push ensures we expand or-patterns | ||
569 | matrix.push(cx, pat); | ||
570 | } | ||
571 | |||
572 | matrix | ||
573 | } | ||
574 | } | ||
575 | |||
576 | #[derive(Clone, Debug, PartialEq)] | ||
577 | /// An indication of the usefulness of a given match arm, where | ||
578 | /// usefulness is defined as matching some patterns which were | ||
579 | /// not matched by an prior match arms. | ||
580 | /// | ||
581 | /// We may eventually need an `Unknown` variant here. | ||
582 | pub enum Usefulness { | ||
583 | Useful, | ||
584 | NotUseful, | ||
585 | } | ||
586 | |||
587 | pub struct MatchCheckCtx<'a> { | ||
588 | pub match_expr: Idx<Expr>, | ||
589 | pub body: Arc<Body>, | ||
590 | pub infer: Arc<InferenceResult>, | ||
591 | pub db: &'a dyn HirDatabase, | ||
592 | } | ||
593 | |||
594 | /// Given a set of patterns `matrix`, and pattern to consider `v`, determines | ||
595 | /// whether `v` is useful. A pattern is useful if it covers cases which were | ||
596 | /// not previously covered. | ||
597 | /// | ||
598 | /// When calling this function externally (that is, not the recursive calls) it | ||
599 | /// expected that you have already type checked the match arms. All patterns in | ||
600 | /// matrix should be the same type as v, as well as they should all be the same | ||
601 | /// type as the match expression. | ||
602 | pub(crate) fn is_useful( | ||
603 | cx: &MatchCheckCtx, | ||
604 | matrix: &Matrix, | ||
605 | v: &PatStack, | ||
606 | ) -> MatchCheckResult<Usefulness> { | ||
607 | // Handle two special cases: | ||
608 | // - enum with no variants | ||
609 | // - `!` type | ||
610 | // In those cases, no match arm is useful. | ||
611 | match cx.infer[cx.match_expr].strip_references() { | ||
612 | Ty::Apply(ApplicationTy { ctor: TypeCtor::Adt(AdtId::EnumId(enum_id)), .. }) => { | ||
613 | if cx.db.enum_data(*enum_id).variants.is_empty() { | ||
614 | return Ok(Usefulness::NotUseful); | ||
615 | } | ||
616 | } | ||
617 | Ty::Apply(ApplicationTy { ctor: TypeCtor::Never, .. }) => { | ||
618 | return Ok(Usefulness::NotUseful); | ||
619 | } | ||
620 | _ => (), | ||
621 | } | ||
622 | |||
623 | let head = match v.get_head() { | ||
624 | Some(head) => head, | ||
625 | None => { | ||
626 | let result = if matrix.is_empty() { Usefulness::Useful } else { Usefulness::NotUseful }; | ||
627 | |||
628 | return Ok(result); | ||
629 | } | ||
630 | }; | ||
631 | |||
632 | if let Pat::Or(pat_ids) = head.as_pat(cx) { | ||
633 | let mut found_unimplemented = false; | ||
634 | let any_useful = pat_ids.iter().any(|&pat_id| { | ||
635 | let v = PatStack::from_pattern(pat_id); | ||
636 | |||
637 | match is_useful(cx, matrix, &v) { | ||
638 | Ok(Usefulness::Useful) => true, | ||
639 | Ok(Usefulness::NotUseful) => false, | ||
640 | _ => { | ||
641 | found_unimplemented = true; | ||
642 | false | ||
643 | } | ||
644 | } | ||
645 | }); | ||
646 | |||
647 | return if any_useful { | ||
648 | Ok(Usefulness::Useful) | ||
649 | } else if found_unimplemented { | ||
650 | Err(MatchCheckErr::NotImplemented) | ||
651 | } else { | ||
652 | Ok(Usefulness::NotUseful) | ||
653 | }; | ||
654 | } | ||
655 | |||
656 | if let Some(constructor) = pat_constructor(cx, head)? { | ||
657 | let matrix = matrix.specialize_constructor(&cx, &constructor)?; | ||
658 | let v = v | ||
659 | .specialize_constructor(&cx, &constructor)? | ||
660 | .expect("we know this can't fail because we get the constructor from `v.head()` above"); | ||
661 | |||
662 | is_useful(&cx, &matrix, &v) | ||
663 | } else { | ||
664 | // expanding wildcard | ||
665 | let mut used_constructors: Vec<Constructor> = vec![]; | ||
666 | for pat in matrix.heads() { | ||
667 | if let Some(constructor) = pat_constructor(cx, pat)? { | ||
668 | used_constructors.push(constructor); | ||
669 | } | ||
670 | } | ||
671 | |||
672 | // We assume here that the first constructor is the "correct" type. Since we | ||
673 | // only care about the "type" of the constructor (i.e. if it is a bool we | ||
674 | // don't care about the value), this assumption should be valid as long as | ||
675 | // the match statement is well formed. We currently uphold this invariant by | ||
676 | // filtering match arms before calling `is_useful`, only passing in match arms | ||
677 | // whose type matches the type of the match expression. | ||
678 | match &used_constructors.first() { | ||
679 | Some(constructor) if all_constructors_covered(&cx, constructor, &used_constructors) => { | ||
680 | // If all constructors are covered, then we need to consider whether | ||
681 | // any values are covered by this wildcard. | ||
682 | // | ||
683 | // For example, with matrix '[[Some(true)], [None]]', all | ||
684 | // constructors are covered (`Some`/`None`), so we need | ||
685 | // to perform specialization to see that our wildcard will cover | ||
686 | // the `Some(false)` case. | ||
687 | // | ||
688 | // Here we create a constructor for each variant and then check | ||
689 | // usefulness after specializing for that constructor. | ||
690 | let mut found_unimplemented = false; | ||
691 | for constructor in constructor.all_constructors(cx) { | ||
692 | let matrix = matrix.specialize_constructor(&cx, &constructor)?; | ||
693 | let v = v.expand_wildcard(&cx, &constructor)?; | ||
694 | |||
695 | match is_useful(&cx, &matrix, &v) { | ||
696 | Ok(Usefulness::Useful) => return Ok(Usefulness::Useful), | ||
697 | Ok(Usefulness::NotUseful) => continue, | ||
698 | _ => found_unimplemented = true, | ||
699 | }; | ||
700 | } | ||
701 | |||
702 | if found_unimplemented { | ||
703 | Err(MatchCheckErr::NotImplemented) | ||
704 | } else { | ||
705 | Ok(Usefulness::NotUseful) | ||
706 | } | ||
707 | } | ||
708 | _ => { | ||
709 | // Either not all constructors are covered, or the only other arms | ||
710 | // are wildcards. Either way, this pattern is useful if it is useful | ||
711 | // when compared to those arms with wildcards. | ||
712 | let matrix = matrix.specialize_wildcard(&cx); | ||
713 | let v = v.to_tail(); | ||
714 | |||
715 | is_useful(&cx, &matrix, &v) | ||
716 | } | ||
717 | } | ||
718 | } | ||
719 | } | ||
720 | |||
721 | #[derive(Debug, Clone, Copy)] | ||
722 | /// Similar to TypeCtor, but includes additional information about the specific | ||
723 | /// value being instantiated. For example, TypeCtor::Bool doesn't contain the | ||
724 | /// boolean value. | ||
725 | enum Constructor { | ||
726 | Bool(bool), | ||
727 | Tuple { arity: usize }, | ||
728 | Enum(EnumVariantId), | ||
729 | } | ||
730 | |||
731 | impl Constructor { | ||
732 | fn arity(&self, cx: &MatchCheckCtx) -> MatchCheckResult<usize> { | ||
733 | let arity = match self { | ||
734 | Constructor::Bool(_) => 0, | ||
735 | Constructor::Tuple { arity } => *arity, | ||
736 | Constructor::Enum(e) => { | ||
737 | match cx.db.enum_data(e.parent).variants[e.local_id].variant_data.as_ref() { | ||
738 | VariantData::Tuple(struct_field_data) => struct_field_data.len(), | ||
739 | VariantData::Record(struct_field_data) => struct_field_data.len(), | ||
740 | VariantData::Unit => 0, | ||
741 | } | ||
742 | } | ||
743 | }; | ||
744 | |||
745 | Ok(arity) | ||
746 | } | ||
747 | |||
748 | fn all_constructors(&self, cx: &MatchCheckCtx) -> Vec<Constructor> { | ||
749 | match self { | ||
750 | Constructor::Bool(_) => vec![Constructor::Bool(true), Constructor::Bool(false)], | ||
751 | Constructor::Tuple { .. } => vec![*self], | ||
752 | Constructor::Enum(e) => cx | ||
753 | .db | ||
754 | .enum_data(e.parent) | ||
755 | .variants | ||
756 | .iter() | ||
757 | .map(|(local_id, _)| { | ||
758 | Constructor::Enum(EnumVariantId { parent: e.parent, local_id }) | ||
759 | }) | ||
760 | .collect(), | ||
761 | } | ||
762 | } | ||
763 | } | ||
764 | |||
765 | /// Returns the constructor for the given pattern. Should only return None | ||
766 | /// in the case of a Wild pattern. | ||
767 | fn pat_constructor(cx: &MatchCheckCtx, pat: PatIdOrWild) -> MatchCheckResult<Option<Constructor>> { | ||
768 | let res = match pat.as_pat(cx) { | ||
769 | Pat::Wild => None, | ||
770 | // FIXME somehow create the Tuple constructor with the proper arity. If there are | ||
771 | // ellipsis, the arity is not equal to the number of patterns. | ||
772 | Pat::Tuple { args: pats, ellipsis } if ellipsis.is_none() => { | ||
773 | Some(Constructor::Tuple { arity: pats.len() }) | ||
774 | } | ||
775 | Pat::Lit(lit_expr) => match cx.body.exprs[lit_expr] { | ||
776 | Expr::Literal(Literal::Bool(val)) => Some(Constructor::Bool(val)), | ||
777 | _ => return Err(MatchCheckErr::NotImplemented), | ||
778 | }, | ||
779 | Pat::TupleStruct { .. } | Pat::Path(_) | Pat::Record { .. } => { | ||
780 | let pat_id = pat.as_id().expect("we already know this pattern is not a wild"); | ||
781 | let variant_id = | ||
782 | cx.infer.variant_resolution_for_pat(pat_id).ok_or(MatchCheckErr::Unknown)?; | ||
783 | match variant_id { | ||
784 | VariantId::EnumVariantId(enum_variant_id) => { | ||
785 | Some(Constructor::Enum(enum_variant_id)) | ||
786 | } | ||
787 | _ => return Err(MatchCheckErr::NotImplemented), | ||
788 | } | ||
789 | } | ||
790 | _ => return Err(MatchCheckErr::NotImplemented), | ||
791 | }; | ||
792 | |||
793 | Ok(res) | ||
794 | } | ||
795 | |||
796 | fn all_constructors_covered( | ||
797 | cx: &MatchCheckCtx, | ||
798 | constructor: &Constructor, | ||
799 | used_constructors: &[Constructor], | ||
800 | ) -> bool { | ||
801 | match constructor { | ||
802 | Constructor::Tuple { arity } => { | ||
803 | used_constructors.iter().any(|constructor| match constructor { | ||
804 | Constructor::Tuple { arity: used_arity } => arity == used_arity, | ||
805 | _ => false, | ||
806 | }) | ||
807 | } | ||
808 | Constructor::Bool(_) => { | ||
809 | if used_constructors.is_empty() { | ||
810 | return false; | ||
811 | } | ||
812 | |||
813 | let covers_true = | ||
814 | used_constructors.iter().any(|c| matches!(c, Constructor::Bool(true))); | ||
815 | let covers_false = | ||
816 | used_constructors.iter().any(|c| matches!(c, Constructor::Bool(false))); | ||
817 | |||
818 | covers_true && covers_false | ||
819 | } | ||
820 | Constructor::Enum(e) => cx.db.enum_data(e.parent).variants.iter().all(|(id, _)| { | ||
821 | for constructor in used_constructors { | ||
822 | if let Constructor::Enum(e) = constructor { | ||
823 | if id == e.local_id { | ||
824 | return true; | ||
825 | } | ||
826 | } | ||
827 | } | ||
828 | |||
829 | false | ||
830 | }), | ||
831 | } | ||
832 | } | ||
833 | |||
834 | fn enum_variant_matches(cx: &MatchCheckCtx, pat_id: PatId, enum_variant_id: EnumVariantId) -> bool { | ||
835 | Some(enum_variant_id.into()) == cx.infer.variant_resolution_for_pat(pat_id) | ||
836 | } | ||
837 | |||
838 | #[cfg(test)] | ||
839 | mod tests { | ||
840 | pub(super) use insta::assert_snapshot; | ||
841 | pub(super) use ra_db::fixture::WithFixture; | ||
842 | |||
843 | pub(super) use crate::{diagnostics::MissingMatchArms, test_db::TestDB}; | ||
844 | |||
845 | pub(super) fn check_diagnostic_message(ra_fixture: &str) -> String { | ||
846 | TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>().0 | ||
847 | } | ||
848 | |||
849 | pub(super) fn check_diagnostic(ra_fixture: &str) { | ||
850 | let diagnostic_count = | ||
851 | TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>().1; | ||
852 | |||
853 | assert_eq!(1, diagnostic_count, "no diagnostic reported"); | ||
854 | } | ||
855 | |||
856 | pub(super) fn check_no_diagnostic(ra_fixture: &str) { | ||
857 | let (s, diagnostic_count) = | ||
858 | TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>(); | ||
859 | |||
860 | assert_eq!(0, diagnostic_count, "expected no diagnostic, found one: {}", s); | ||
861 | } | ||
862 | |||
863 | #[test] | ||
864 | fn empty_tuple_no_arms_diagnostic_message() { | ||
865 | assert_snapshot!( | ||
866 | check_diagnostic_message(r" | ||
867 | fn test_fn() { | ||
868 | match () { | ||
869 | } | ||
870 | } | ||
871 | "), | ||
872 | @"\"()\": Missing match arm\n" | ||
873 | ); | ||
874 | } | ||
875 | |||
876 | #[test] | ||
877 | fn empty_tuple_no_arms() { | ||
878 | check_diagnostic( | ||
879 | r" | ||
880 | fn test_fn() { | ||
881 | match () { | ||
882 | } | ||
883 | } | ||
884 | ", | ||
885 | ); | ||
886 | } | ||
887 | |||
888 | #[test] | ||
889 | fn empty_tuple_wild() { | ||
890 | check_no_diagnostic( | ||
891 | r" | ||
892 | fn test_fn() { | ||
893 | match () { | ||
894 | _ => {} | ||
895 | } | ||
896 | } | ||
897 | ", | ||
898 | ); | ||
899 | } | ||
900 | |||
901 | #[test] | ||
902 | fn empty_tuple_no_diagnostic() { | ||
903 | check_no_diagnostic( | ||
904 | r" | ||
905 | fn test_fn() { | ||
906 | match () { | ||
907 | () => {} | ||
908 | } | ||
909 | } | ||
910 | ", | ||
911 | ); | ||
912 | } | ||
913 | |||
914 | #[test] | ||
915 | fn tuple_of_empty_tuple_no_arms() { | ||
916 | check_diagnostic( | ||
917 | r" | ||
918 | fn test_fn() { | ||
919 | match (()) { | ||
920 | } | ||
921 | } | ||
922 | ", | ||
923 | ); | ||
924 | } | ||
925 | |||
926 | #[test] | ||
927 | fn tuple_of_empty_tuple_no_diagnostic() { | ||
928 | check_no_diagnostic( | ||
929 | r" | ||
930 | fn test_fn() { | ||
931 | match (()) { | ||
932 | (()) => {} | ||
933 | } | ||
934 | } | ||
935 | ", | ||
936 | ); | ||
937 | } | ||
938 | |||
939 | #[test] | ||
940 | fn tuple_of_two_empty_tuple_no_arms() { | ||
941 | check_diagnostic( | ||
942 | r" | ||
943 | fn test_fn() { | ||
944 | match ((), ()) { | ||
945 | } | ||
946 | } | ||
947 | ", | ||
948 | ); | ||
949 | } | ||
950 | |||
951 | #[test] | ||
952 | fn tuple_of_two_empty_tuple_no_diagnostic() { | ||
953 | check_no_diagnostic( | ||
954 | r" | ||
955 | fn test_fn() { | ||
956 | match ((), ()) { | ||
957 | ((), ()) => {} | ||
958 | } | ||
959 | } | ||
960 | ", | ||
961 | ); | ||
962 | } | ||
963 | |||
964 | #[test] | ||
965 | fn bool_no_arms() { | ||
966 | check_diagnostic( | ||
967 | r" | ||
968 | fn test_fn() { | ||
969 | match false { | ||
970 | } | ||
971 | } | ||
972 | ", | ||
973 | ); | ||
974 | } | ||
975 | |||
976 | #[test] | ||
977 | fn bool_missing_arm() { | ||
978 | check_diagnostic( | ||
979 | r" | ||
980 | fn test_fn() { | ||
981 | match false { | ||
982 | true => {} | ||
983 | } | ||
984 | } | ||
985 | ", | ||
986 | ); | ||
987 | } | ||
988 | |||
989 | #[test] | ||
990 | fn bool_no_diagnostic() { | ||
991 | check_no_diagnostic( | ||
992 | r" | ||
993 | fn test_fn() { | ||
994 | match false { | ||
995 | true => {} | ||
996 | false => {} | ||
997 | } | ||
998 | } | ||
999 | ", | ||
1000 | ); | ||
1001 | } | ||
1002 | |||
1003 | #[test] | ||
1004 | fn tuple_of_bools_no_arms() { | ||
1005 | check_diagnostic( | ||
1006 | r" | ||
1007 | fn test_fn() { | ||
1008 | match (false, true) { | ||
1009 | } | ||
1010 | } | ||
1011 | ", | ||
1012 | ); | ||
1013 | } | ||
1014 | |||
1015 | #[test] | ||
1016 | fn tuple_of_bools_missing_arms() { | ||
1017 | check_diagnostic( | ||
1018 | r" | ||
1019 | fn test_fn() { | ||
1020 | match (false, true) { | ||
1021 | (true, true) => {}, | ||
1022 | } | ||
1023 | } | ||
1024 | ", | ||
1025 | ); | ||
1026 | } | ||
1027 | |||
1028 | #[test] | ||
1029 | fn tuple_of_bools_missing_arm() { | ||
1030 | check_diagnostic( | ||
1031 | r" | ||
1032 | fn test_fn() { | ||
1033 | match (false, true) { | ||
1034 | (false, true) => {}, | ||
1035 | (false, false) => {}, | ||
1036 | (true, false) => {}, | ||
1037 | } | ||
1038 | } | ||
1039 | ", | ||
1040 | ); | ||
1041 | } | ||
1042 | |||
1043 | #[test] | ||
1044 | fn tuple_of_bools_with_wilds() { | ||
1045 | check_no_diagnostic( | ||
1046 | r" | ||
1047 | fn test_fn() { | ||
1048 | match (false, true) { | ||
1049 | (false, _) => {}, | ||
1050 | (true, false) => {}, | ||
1051 | (_, true) => {}, | ||
1052 | } | ||
1053 | } | ||
1054 | ", | ||
1055 | ); | ||
1056 | } | ||
1057 | |||
1058 | #[test] | ||
1059 | fn tuple_of_bools_no_diagnostic() { | ||
1060 | check_no_diagnostic( | ||
1061 | r" | ||
1062 | fn test_fn() { | ||
1063 | match (false, true) { | ||
1064 | (true, true) => {}, | ||
1065 | (true, false) => {}, | ||
1066 | (false, true) => {}, | ||
1067 | (false, false) => {}, | ||
1068 | } | ||
1069 | } | ||
1070 | ", | ||
1071 | ); | ||
1072 | } | ||
1073 | |||
1074 | #[test] | ||
1075 | fn tuple_of_bools_binding_missing_arms() { | ||
1076 | check_diagnostic( | ||
1077 | r" | ||
1078 | fn test_fn() { | ||
1079 | match (false, true) { | ||
1080 | (true, _x) => {}, | ||
1081 | } | ||
1082 | } | ||
1083 | ", | ||
1084 | ); | ||
1085 | } | ||
1086 | |||
1087 | #[test] | ||
1088 | fn tuple_of_bools_binding_no_diagnostic() { | ||
1089 | check_no_diagnostic( | ||
1090 | r" | ||
1091 | fn test_fn() { | ||
1092 | match (false, true) { | ||
1093 | (true, _x) => {}, | ||
1094 | (false, true) => {}, | ||
1095 | (false, false) => {}, | ||
1096 | } | ||
1097 | } | ||
1098 | ", | ||
1099 | ); | ||
1100 | } | ||
1101 | |||
1102 | #[test] | ||
1103 | fn tuple_of_bools_with_ellipsis_at_end_no_diagnostic() { | ||
1104 | check_no_diagnostic( | ||
1105 | r" | ||
1106 | fn test_fn() { | ||
1107 | match (false, true, false) { | ||
1108 | (false, ..) => {}, | ||
1109 | (true, ..) => {}, | ||
1110 | } | ||
1111 | } | ||
1112 | ", | ||
1113 | ); | ||
1114 | } | ||
1115 | |||
1116 | #[test] | ||
1117 | fn tuple_of_bools_with_ellipsis_at_beginning_no_diagnostic() { | ||
1118 | check_no_diagnostic( | ||
1119 | r" | ||
1120 | fn test_fn() { | ||
1121 | match (false, true, false) { | ||
1122 | (.., false) => {}, | ||
1123 | (.., true) => {}, | ||
1124 | } | ||
1125 | } | ||
1126 | ", | ||
1127 | ); | ||
1128 | } | ||
1129 | |||
1130 | #[test] | ||
1131 | fn tuple_of_bools_with_ellipsis_no_diagnostic() { | ||
1132 | check_no_diagnostic( | ||
1133 | r" | ||
1134 | fn test_fn() { | ||
1135 | match (false, true, false) { | ||
1136 | (..) => {}, | ||
1137 | } | ||
1138 | } | ||
1139 | ", | ||
1140 | ); | ||
1141 | } | ||
1142 | |||
1143 | #[test] | ||
1144 | fn tuple_of_tuple_and_bools_no_arms() { | ||
1145 | check_diagnostic( | ||
1146 | r" | ||
1147 | fn test_fn() { | ||
1148 | match (false, ((), false)) { | ||
1149 | } | ||
1150 | } | ||
1151 | ", | ||
1152 | ); | ||
1153 | } | ||
1154 | |||
1155 | #[test] | ||
1156 | fn tuple_of_tuple_and_bools_missing_arms() { | ||
1157 | check_diagnostic( | ||
1158 | r" | ||
1159 | fn test_fn() { | ||
1160 | match (false, ((), false)) { | ||
1161 | (true, ((), true)) => {}, | ||
1162 | } | ||
1163 | } | ||
1164 | ", | ||
1165 | ); | ||
1166 | } | ||
1167 | |||
1168 | #[test] | ||
1169 | fn tuple_of_tuple_and_bools_no_diagnostic() { | ||
1170 | check_no_diagnostic( | ||
1171 | r" | ||
1172 | fn test_fn() { | ||
1173 | match (false, ((), false)) { | ||
1174 | (true, ((), true)) => {}, | ||
1175 | (true, ((), false)) => {}, | ||
1176 | (false, ((), true)) => {}, | ||
1177 | (false, ((), false)) => {}, | ||
1178 | } | ||
1179 | } | ||
1180 | ", | ||
1181 | ); | ||
1182 | } | ||
1183 | |||
1184 | #[test] | ||
1185 | fn tuple_of_tuple_and_bools_wildcard_missing_arms() { | ||
1186 | check_diagnostic( | ||
1187 | r" | ||
1188 | fn test_fn() { | ||
1189 | match (false, ((), false)) { | ||
1190 | (true, _) => {}, | ||
1191 | } | ||
1192 | } | ||
1193 | ", | ||
1194 | ); | ||
1195 | } | ||
1196 | |||
1197 | #[test] | ||
1198 | fn tuple_of_tuple_and_bools_wildcard_no_diagnostic() { | ||
1199 | check_no_diagnostic( | ||
1200 | r" | ||
1201 | fn test_fn() { | ||
1202 | match (false, ((), false)) { | ||
1203 | (true, ((), true)) => {}, | ||
1204 | (true, ((), false)) => {}, | ||
1205 | (false, _) => {}, | ||
1206 | } | ||
1207 | } | ||
1208 | ", | ||
1209 | ); | ||
1210 | } | ||
1211 | |||
1212 | #[test] | ||
1213 | fn enum_no_arms() { | ||
1214 | check_diagnostic( | ||
1215 | r" | ||
1216 | enum Either { | ||
1217 | A, | ||
1218 | B, | ||
1219 | } | ||
1220 | fn test_fn() { | ||
1221 | match Either::A { | ||
1222 | } | ||
1223 | } | ||
1224 | ", | ||
1225 | ); | ||
1226 | } | ||
1227 | |||
1228 | #[test] | ||
1229 | fn enum_missing_arms() { | ||
1230 | check_diagnostic( | ||
1231 | r" | ||
1232 | enum Either { | ||
1233 | A, | ||
1234 | B, | ||
1235 | } | ||
1236 | fn test_fn() { | ||
1237 | match Either::B { | ||
1238 | Either::A => {}, | ||
1239 | } | ||
1240 | } | ||
1241 | ", | ||
1242 | ); | ||
1243 | } | ||
1244 | |||
1245 | #[test] | ||
1246 | fn enum_no_diagnostic() { | ||
1247 | check_no_diagnostic( | ||
1248 | r" | ||
1249 | enum Either { | ||
1250 | A, | ||
1251 | B, | ||
1252 | } | ||
1253 | fn test_fn() { | ||
1254 | match Either::B { | ||
1255 | Either::A => {}, | ||
1256 | Either::B => {}, | ||
1257 | } | ||
1258 | } | ||
1259 | ", | ||
1260 | ); | ||
1261 | } | ||
1262 | |||
1263 | #[test] | ||
1264 | fn enum_ref_missing_arms() { | ||
1265 | check_diagnostic( | ||
1266 | r" | ||
1267 | enum Either { | ||
1268 | A, | ||
1269 | B, | ||
1270 | } | ||
1271 | fn test_fn() { | ||
1272 | match &Either::B { | ||
1273 | Either::A => {}, | ||
1274 | } | ||
1275 | } | ||
1276 | ", | ||
1277 | ); | ||
1278 | } | ||
1279 | |||
1280 | #[test] | ||
1281 | fn enum_ref_no_diagnostic() { | ||
1282 | check_no_diagnostic( | ||
1283 | r" | ||
1284 | enum Either { | ||
1285 | A, | ||
1286 | B, | ||
1287 | } | ||
1288 | fn test_fn() { | ||
1289 | match &Either::B { | ||
1290 | Either::A => {}, | ||
1291 | Either::B => {}, | ||
1292 | } | ||
1293 | } | ||
1294 | ", | ||
1295 | ); | ||
1296 | } | ||
1297 | |||
1298 | #[test] | ||
1299 | fn enum_containing_bool_no_arms() { | ||
1300 | check_diagnostic( | ||
1301 | r" | ||
1302 | enum Either { | ||
1303 | A(bool), | ||
1304 | B, | ||
1305 | } | ||
1306 | fn test_fn() { | ||
1307 | match Either::B { | ||
1308 | } | ||
1309 | } | ||
1310 | ", | ||
1311 | ); | ||
1312 | } | ||
1313 | |||
1314 | #[test] | ||
1315 | fn enum_containing_bool_missing_arms() { | ||
1316 | check_diagnostic( | ||
1317 | r" | ||
1318 | enum Either { | ||
1319 | A(bool), | ||
1320 | B, | ||
1321 | } | ||
1322 | fn test_fn() { | ||
1323 | match Either::B { | ||
1324 | Either::A(true) => (), | ||
1325 | Either::B => (), | ||
1326 | } | ||
1327 | } | ||
1328 | ", | ||
1329 | ); | ||
1330 | } | ||
1331 | |||
1332 | #[test] | ||
1333 | fn enum_containing_bool_no_diagnostic() { | ||
1334 | check_no_diagnostic( | ||
1335 | r" | ||
1336 | enum Either { | ||
1337 | A(bool), | ||
1338 | B, | ||
1339 | } | ||
1340 | fn test_fn() { | ||
1341 | match Either::B { | ||
1342 | Either::A(true) => (), | ||
1343 | Either::A(false) => (), | ||
1344 | Either::B => (), | ||
1345 | } | ||
1346 | } | ||
1347 | ", | ||
1348 | ); | ||
1349 | } | ||
1350 | |||
1351 | #[test] | ||
1352 | fn enum_containing_bool_with_wild_no_diagnostic() { | ||
1353 | check_no_diagnostic( | ||
1354 | r" | ||
1355 | enum Either { | ||
1356 | A(bool), | ||
1357 | B, | ||
1358 | } | ||
1359 | fn test_fn() { | ||
1360 | match Either::B { | ||
1361 | Either::B => (), | ||
1362 | _ => (), | ||
1363 | } | ||
1364 | } | ||
1365 | ", | ||
1366 | ); | ||
1367 | } | ||
1368 | |||
1369 | #[test] | ||
1370 | fn enum_containing_bool_with_wild_2_no_diagnostic() { | ||
1371 | check_no_diagnostic( | ||
1372 | r" | ||
1373 | enum Either { | ||
1374 | A(bool), | ||
1375 | B, | ||
1376 | } | ||
1377 | fn test_fn() { | ||
1378 | match Either::B { | ||
1379 | Either::A(_) => (), | ||
1380 | Either::B => (), | ||
1381 | } | ||
1382 | } | ||
1383 | ", | ||
1384 | ); | ||
1385 | } | ||
1386 | |||
1387 | #[test] | ||
1388 | fn enum_different_sizes_missing_arms() { | ||
1389 | check_diagnostic( | ||
1390 | r" | ||
1391 | enum Either { | ||
1392 | A(bool), | ||
1393 | B(bool, bool), | ||
1394 | } | ||
1395 | fn test_fn() { | ||
1396 | match Either::A(false) { | ||
1397 | Either::A(_) => (), | ||
1398 | Either::B(false, _) => (), | ||
1399 | } | ||
1400 | } | ||
1401 | ", | ||
1402 | ); | ||
1403 | } | ||
1404 | |||
1405 | #[test] | ||
1406 | fn enum_different_sizes_no_diagnostic() { | ||
1407 | check_no_diagnostic( | ||
1408 | r" | ||
1409 | enum Either { | ||
1410 | A(bool), | ||
1411 | B(bool, bool), | ||
1412 | } | ||
1413 | fn test_fn() { | ||
1414 | match Either::A(false) { | ||
1415 | Either::A(_) => (), | ||
1416 | Either::B(true, _) => (), | ||
1417 | Either::B(false, _) => (), | ||
1418 | } | ||
1419 | } | ||
1420 | ", | ||
1421 | ); | ||
1422 | } | ||
1423 | |||
1424 | #[test] | ||
1425 | fn or_no_diagnostic() { | ||
1426 | check_no_diagnostic( | ||
1427 | r" | ||
1428 | enum Either { | ||
1429 | A(bool), | ||
1430 | B(bool, bool), | ||
1431 | } | ||
1432 | fn test_fn() { | ||
1433 | match Either::A(false) { | ||
1434 | Either::A(true) | Either::A(false) => (), | ||
1435 | Either::B(true, _) => (), | ||
1436 | Either::B(false, _) => (), | ||
1437 | } | ||
1438 | } | ||
1439 | ", | ||
1440 | ); | ||
1441 | } | ||
1442 | |||
1443 | #[test] | ||
1444 | fn tuple_of_enum_no_diagnostic() { | ||
1445 | check_no_diagnostic( | ||
1446 | r" | ||
1447 | enum Either { | ||
1448 | A(bool), | ||
1449 | B(bool, bool), | ||
1450 | } | ||
1451 | enum Either2 { | ||
1452 | C, | ||
1453 | D, | ||
1454 | } | ||
1455 | fn test_fn() { | ||
1456 | match (Either::A(false), Either2::C) { | ||
1457 | (Either::A(true), _) | (Either::A(false), _) => (), | ||
1458 | (Either::B(true, _), Either2::C) => (), | ||
1459 | (Either::B(false, _), Either2::C) => (), | ||
1460 | (Either::B(_, _), Either2::D) => (), | ||
1461 | } | ||
1462 | } | ||
1463 | ", | ||
1464 | ); | ||
1465 | } | ||
1466 | |||
1467 | #[test] | ||
1468 | fn mismatched_types() { | ||
1469 | // Match statements with arms that don't match the | ||
1470 | // expression pattern do not fire this diagnostic. | ||
1471 | check_no_diagnostic( | ||
1472 | r" | ||
1473 | enum Either { | ||
1474 | A, | ||
1475 | B, | ||
1476 | } | ||
1477 | enum Either2 { | ||
1478 | C, | ||
1479 | D, | ||
1480 | } | ||
1481 | fn test_fn() { | ||
1482 | match Either::A { | ||
1483 | Either2::C => (), | ||
1484 | Either2::D => (), | ||
1485 | } | ||
1486 | } | ||
1487 | ", | ||
1488 | ); | ||
1489 | } | ||
1490 | |||
1491 | #[test] | ||
1492 | fn mismatched_types_with_different_arity() { | ||
1493 | // Match statements with arms that don't match the | ||
1494 | // expression pattern do not fire this diagnostic. | ||
1495 | check_no_diagnostic( | ||
1496 | r" | ||
1497 | fn test_fn() { | ||
1498 | match (true, false) { | ||
1499 | (true, false, true) => (), | ||
1500 | (true) => (), | ||
1501 | } | ||
1502 | } | ||
1503 | ", | ||
1504 | ); | ||
1505 | } | ||
1506 | |||
1507 | #[test] | ||
1508 | fn malformed_match_arm_tuple_missing_pattern() { | ||
1509 | // Match statements with arms that don't match the | ||
1510 | // expression pattern do not fire this diagnostic. | ||
1511 | check_no_diagnostic( | ||
1512 | r" | ||
1513 | fn test_fn() { | ||
1514 | match (0) { | ||
1515 | () => (), | ||
1516 | } | ||
1517 | } | ||
1518 | ", | ||
1519 | ); | ||
1520 | } | ||
1521 | |||
1522 | #[test] | ||
1523 | fn malformed_match_arm_tuple_enum_missing_pattern() { | ||
1524 | // We are testing to be sure we don't panic here when the match | ||
1525 | // arm `Either::B` is missing its pattern. | ||
1526 | check_no_diagnostic( | ||
1527 | r" | ||
1528 | enum Either { | ||
1529 | A, | ||
1530 | B(u32), | ||
1531 | } | ||
1532 | fn test_fn() { | ||
1533 | match Either::A { | ||
1534 | Either::A => (), | ||
1535 | Either::B() => (), | ||
1536 | } | ||
1537 | } | ||
1538 | ", | ||
1539 | ); | ||
1540 | } | ||
1541 | |||
1542 | #[test] | ||
1543 | fn enum_not_in_scope() { | ||
1544 | // The enum is not in scope so we don't perform exhaustiveness | ||
1545 | // checking, but we want to be sure we don't panic here (and | ||
1546 | // we don't create a diagnostic). | ||
1547 | check_no_diagnostic( | ||
1548 | r" | ||
1549 | fn test_fn() { | ||
1550 | match Foo::Bar { | ||
1551 | Foo::Baz => (), | ||
1552 | } | ||
1553 | } | ||
1554 | ", | ||
1555 | ); | ||
1556 | } | ||
1557 | |||
1558 | #[test] | ||
1559 | fn expr_diverges() { | ||
1560 | check_no_diagnostic( | ||
1561 | r" | ||
1562 | enum Either { | ||
1563 | A, | ||
1564 | B, | ||
1565 | } | ||
1566 | fn test_fn() { | ||
1567 | match loop {} { | ||
1568 | Either::A => (), | ||
1569 | Either::B => (), | ||
1570 | } | ||
1571 | } | ||
1572 | ", | ||
1573 | ); | ||
1574 | } | ||
1575 | |||
1576 | #[test] | ||
1577 | fn expr_loop_with_break() { | ||
1578 | check_no_diagnostic( | ||
1579 | r" | ||
1580 | enum Either { | ||
1581 | A, | ||
1582 | B, | ||
1583 | } | ||
1584 | fn test_fn() { | ||
1585 | match loop { break Foo::A } { | ||
1586 | Either::A => (), | ||
1587 | Either::B => (), | ||
1588 | } | ||
1589 | } | ||
1590 | ", | ||
1591 | ); | ||
1592 | } | ||
1593 | |||
1594 | #[test] | ||
1595 | fn expr_partially_diverges() { | ||
1596 | check_no_diagnostic( | ||
1597 | r" | ||
1598 | enum Either<T> { | ||
1599 | A(T), | ||
1600 | B, | ||
1601 | } | ||
1602 | fn foo() -> Either<!> { | ||
1603 | Either::B | ||
1604 | } | ||
1605 | fn test_fn() -> u32 { | ||
1606 | match foo() { | ||
1607 | Either::A(val) => val, | ||
1608 | Either::B => 0, | ||
1609 | } | ||
1610 | } | ||
1611 | ", | ||
1612 | ); | ||
1613 | } | ||
1614 | |||
1615 | #[test] | ||
1616 | fn enum_record_no_arms() { | ||
1617 | check_diagnostic( | ||
1618 | r" | ||
1619 | enum Either { | ||
1620 | A { foo: bool }, | ||
1621 | B, | ||
1622 | } | ||
1623 | fn test_fn() { | ||
1624 | let a = Either::A { foo: true }; | ||
1625 | match a { | ||
1626 | } | ||
1627 | } | ||
1628 | ", | ||
1629 | ); | ||
1630 | } | ||
1631 | |||
1632 | #[test] | ||
1633 | fn enum_record_missing_arms() { | ||
1634 | check_diagnostic( | ||
1635 | r" | ||
1636 | enum Either { | ||
1637 | A { foo: bool }, | ||
1638 | B, | ||
1639 | } | ||
1640 | fn test_fn() { | ||
1641 | let a = Either::A { foo: true }; | ||
1642 | match a { | ||
1643 | Either::A { foo: true } => (), | ||
1644 | } | ||
1645 | } | ||
1646 | ", | ||
1647 | ); | ||
1648 | } | ||
1649 | |||
1650 | #[test] | ||
1651 | fn enum_record_no_diagnostic() { | ||
1652 | check_no_diagnostic( | ||
1653 | r" | ||
1654 | enum Either { | ||
1655 | A { foo: bool }, | ||
1656 | B, | ||
1657 | } | ||
1658 | fn test_fn() { | ||
1659 | let a = Either::A { foo: true }; | ||
1660 | match a { | ||
1661 | Either::A { foo: true } => (), | ||
1662 | Either::A { foo: false } => (), | ||
1663 | Either::B => (), | ||
1664 | } | ||
1665 | } | ||
1666 | ", | ||
1667 | ); | ||
1668 | } | ||
1669 | |||
1670 | #[test] | ||
1671 | fn enum_record_missing_field_no_diagnostic() { | ||
1672 | // When `Either::A` is missing a struct member, we don't want | ||
1673 | // to fire the missing match arm diagnostic. This should fire | ||
1674 | // some other diagnostic. | ||
1675 | check_no_diagnostic( | ||
1676 | r" | ||
1677 | enum Either { | ||
1678 | A { foo: bool }, | ||
1679 | B, | ||
1680 | } | ||
1681 | fn test_fn() { | ||
1682 | let a = Either::B; | ||
1683 | match a { | ||
1684 | Either::A { } => (), | ||
1685 | Either::B => (), | ||
1686 | } | ||
1687 | } | ||
1688 | ", | ||
1689 | ); | ||
1690 | } | ||
1691 | |||
1692 | #[test] | ||
1693 | fn enum_record_missing_field_missing_match_arm() { | ||
1694 | // Even though `Either::A` is missing fields, we still want to fire | ||
1695 | // the missing arm diagnostic here, since we know `Either::B` is missing. | ||
1696 | check_diagnostic( | ||
1697 | r" | ||
1698 | enum Either { | ||
1699 | A { foo: bool }, | ||
1700 | B, | ||
1701 | } | ||
1702 | fn test_fn() { | ||
1703 | let a = Either::B; | ||
1704 | match a { | ||
1705 | Either::A { } => (), | ||
1706 | } | ||
1707 | } | ||
1708 | ", | ||
1709 | ); | ||
1710 | } | ||
1711 | |||
1712 | #[test] | ||
1713 | fn enum_record_no_diagnostic_wild() { | ||
1714 | check_no_diagnostic( | ||
1715 | r" | ||
1716 | enum Either { | ||
1717 | A { foo: bool }, | ||
1718 | B, | ||
1719 | } | ||
1720 | fn test_fn() { | ||
1721 | let a = Either::A { foo: true }; | ||
1722 | match a { | ||
1723 | Either::A { foo: _ } => (), | ||
1724 | Either::B => (), | ||
1725 | } | ||
1726 | } | ||
1727 | ", | ||
1728 | ); | ||
1729 | } | ||
1730 | |||
1731 | #[test] | ||
1732 | fn enum_record_fields_out_of_order_missing_arm() { | ||
1733 | check_diagnostic( | ||
1734 | r" | ||
1735 | enum Either { | ||
1736 | A { foo: bool, bar: () }, | ||
1737 | B, | ||
1738 | } | ||
1739 | fn test_fn() { | ||
1740 | let a = Either::A { foo: true }; | ||
1741 | match a { | ||
1742 | Either::A { bar: (), foo: false } => (), | ||
1743 | Either::A { foo: true, bar: () } => (), | ||
1744 | } | ||
1745 | } | ||
1746 | ", | ||
1747 | ); | ||
1748 | } | ||
1749 | |||
1750 | #[test] | ||
1751 | fn enum_record_fields_out_of_order_no_diagnostic() { | ||
1752 | check_no_diagnostic( | ||
1753 | r" | ||
1754 | enum Either { | ||
1755 | A { foo: bool, bar: () }, | ||
1756 | B, | ||
1757 | } | ||
1758 | fn test_fn() { | ||
1759 | let a = Either::A { foo: true }; | ||
1760 | match a { | ||
1761 | Either::A { bar: (), foo: false } => (), | ||
1762 | Either::A { foo: true, bar: () } => (), | ||
1763 | Either::B => (), | ||
1764 | } | ||
1765 | } | ||
1766 | ", | ||
1767 | ); | ||
1768 | } | ||
1769 | |||
1770 | #[test] | ||
1771 | fn enum_record_ellipsis_missing_arm() { | ||
1772 | check_diagnostic( | ||
1773 | r" | ||
1774 | enum Either { | ||
1775 | A { foo: bool, bar: bool }, | ||
1776 | B, | ||
1777 | } | ||
1778 | fn test_fn() { | ||
1779 | match Either::B { | ||
1780 | Either::A { foo: true, .. } => (), | ||
1781 | Either::B => (), | ||
1782 | } | ||
1783 | } | ||
1784 | ", | ||
1785 | ); | ||
1786 | } | ||
1787 | |||
1788 | #[test] | ||
1789 | fn enum_record_ellipsis_no_diagnostic() { | ||
1790 | check_no_diagnostic( | ||
1791 | r" | ||
1792 | enum Either { | ||
1793 | A { foo: bool, bar: bool }, | ||
1794 | B, | ||
1795 | } | ||
1796 | fn test_fn() { | ||
1797 | let a = Either::A { foo: true }; | ||
1798 | match a { | ||
1799 | Either::A { foo: true, .. } => (), | ||
1800 | Either::A { foo: false, .. } => (), | ||
1801 | Either::B => (), | ||
1802 | } | ||
1803 | } | ||
1804 | ", | ||
1805 | ); | ||
1806 | } | ||
1807 | |||
1808 | #[test] | ||
1809 | fn enum_record_ellipsis_all_fields_missing_arm() { | ||
1810 | check_diagnostic( | ||
1811 | r" | ||
1812 | enum Either { | ||
1813 | A { foo: bool, bar: bool }, | ||
1814 | B, | ||
1815 | } | ||
1816 | fn test_fn() { | ||
1817 | let a = Either::B; | ||
1818 | match a { | ||
1819 | Either::A { .. } => (), | ||
1820 | } | ||
1821 | } | ||
1822 | ", | ||
1823 | ); | ||
1824 | } | ||
1825 | |||
1826 | #[test] | ||
1827 | fn enum_record_ellipsis_all_fields_no_diagnostic() { | ||
1828 | check_no_diagnostic( | ||
1829 | r" | ||
1830 | enum Either { | ||
1831 | A { foo: bool, bar: bool }, | ||
1832 | B, | ||
1833 | } | ||
1834 | fn test_fn() { | ||
1835 | let a = Either::B; | ||
1836 | match a { | ||
1837 | Either::A { .. } => (), | ||
1838 | Either::B => (), | ||
1839 | } | ||
1840 | } | ||
1841 | ", | ||
1842 | ); | ||
1843 | } | ||
1844 | |||
1845 | #[test] | ||
1846 | fn enum_tuple_partial_ellipsis_no_diagnostic() { | ||
1847 | check_no_diagnostic( | ||
1848 | r" | ||
1849 | enum Either { | ||
1850 | A(bool, bool, bool, bool), | ||
1851 | B, | ||
1852 | } | ||
1853 | fn test_fn() { | ||
1854 | match Either::B { | ||
1855 | Either::A(true, .., true) => {}, | ||
1856 | Either::A(true, .., false) => {}, | ||
1857 | Either::A(false, .., true) => {}, | ||
1858 | Either::A(false, .., false) => {}, | ||
1859 | Either::B => {}, | ||
1860 | } | ||
1861 | } | ||
1862 | ", | ||
1863 | ); | ||
1864 | } | ||
1865 | |||
1866 | #[test] | ||
1867 | fn enum_tuple_partial_ellipsis_2_no_diagnostic() { | ||
1868 | check_no_diagnostic( | ||
1869 | r" | ||
1870 | enum Either { | ||
1871 | A(bool, bool, bool, bool), | ||
1872 | B, | ||
1873 | } | ||
1874 | fn test_fn() { | ||
1875 | match Either::B { | ||
1876 | Either::A(true, .., true) => {}, | ||
1877 | Either::A(true, .., false) => {}, | ||
1878 | Either::A(.., true) => {}, | ||
1879 | Either::A(.., false) => {}, | ||
1880 | Either::B => {}, | ||
1881 | } | ||
1882 | } | ||
1883 | ", | ||
1884 | ); | ||
1885 | } | ||
1886 | |||
1887 | #[test] | ||
1888 | fn enum_tuple_partial_ellipsis_missing_arm() { | ||
1889 | check_diagnostic( | ||
1890 | r" | ||
1891 | enum Either { | ||
1892 | A(bool, bool, bool, bool), | ||
1893 | B, | ||
1894 | } | ||
1895 | fn test_fn() { | ||
1896 | match Either::B { | ||
1897 | Either::A(true, .., true) => {}, | ||
1898 | Either::A(true, .., false) => {}, | ||
1899 | Either::A(false, .., false) => {}, | ||
1900 | Either::B => {}, | ||
1901 | } | ||
1902 | } | ||
1903 | ", | ||
1904 | ); | ||
1905 | } | ||
1906 | |||
1907 | #[test] | ||
1908 | fn enum_tuple_partial_ellipsis_2_missing_arm() { | ||
1909 | check_diagnostic( | ||
1910 | r" | ||
1911 | enum Either { | ||
1912 | A(bool, bool, bool, bool), | ||
1913 | B, | ||
1914 | } | ||
1915 | fn test_fn() { | ||
1916 | match Either::B { | ||
1917 | Either::A(true, .., true) => {}, | ||
1918 | Either::A(true, .., false) => {}, | ||
1919 | Either::A(.., true) => {}, | ||
1920 | Either::B => {}, | ||
1921 | } | ||
1922 | } | ||
1923 | ", | ||
1924 | ); | ||
1925 | } | ||
1926 | |||
1927 | #[test] | ||
1928 | fn enum_tuple_ellipsis_no_diagnostic() { | ||
1929 | check_no_diagnostic( | ||
1930 | r" | ||
1931 | enum Either { | ||
1932 | A(bool, bool, bool, bool), | ||
1933 | B, | ||
1934 | } | ||
1935 | fn test_fn() { | ||
1936 | match Either::B { | ||
1937 | Either::A(..) => {}, | ||
1938 | Either::B => {}, | ||
1939 | } | ||
1940 | } | ||
1941 | ", | ||
1942 | ); | ||
1943 | } | ||
1944 | |||
1945 | #[test] | ||
1946 | fn enum_never() { | ||
1947 | check_no_diagnostic( | ||
1948 | r" | ||
1949 | enum Never {} | ||
1950 | |||
1951 | fn test_fn(never: Never) { | ||
1952 | match never {} | ||
1953 | } | ||
1954 | ", | ||
1955 | ); | ||
1956 | } | ||
1957 | |||
1958 | #[test] | ||
1959 | fn type_never() { | ||
1960 | check_no_diagnostic( | ||
1961 | r" | ||
1962 | fn test_fn(never: !) { | ||
1963 | match never {} | ||
1964 | } | ||
1965 | ", | ||
1966 | ); | ||
1967 | } | ||
1968 | |||
1969 | #[test] | ||
1970 | fn enum_never_ref() { | ||
1971 | check_no_diagnostic( | ||
1972 | r" | ||
1973 | enum Never {} | ||
1974 | |||
1975 | fn test_fn(never: &Never) { | ||
1976 | match never {} | ||
1977 | } | ||
1978 | ", | ||
1979 | ); | ||
1980 | } | ||
1981 | |||
1982 | #[test] | ||
1983 | fn expr_diverges_missing_arm() { | ||
1984 | check_no_diagnostic( | ||
1985 | r" | ||
1986 | enum Either { | ||
1987 | A, | ||
1988 | B, | ||
1989 | } | ||
1990 | fn test_fn() { | ||
1991 | match loop {} { | ||
1992 | Either::A => (), | ||
1993 | } | ||
1994 | } | ||
1995 | ", | ||
1996 | ); | ||
1997 | } | ||
1998 | |||
1999 | #[test] | ||
2000 | fn or_pattern_panic() { | ||
2001 | check_no_diagnostic( | ||
2002 | r" | ||
2003 | pub enum Category { | ||
2004 | Infinity, | ||
2005 | Zero, | ||
2006 | } | ||
2007 | |||
2008 | fn panic(a: Category, b: Category) { | ||
2009 | match (a, b) { | ||
2010 | (Category::Zero | Category::Infinity, _) => {} | ||
2011 | (_, Category::Zero | Category::Infinity) => {} | ||
2012 | } | ||
2013 | } | ||
2014 | ", | ||
2015 | ); | ||
2016 | } | ||
2017 | |||
2018 | #[test] | ||
2019 | fn or_pattern_panic_2() { | ||
2020 | // FIXME: This is a false positive, but the code used to cause a panic in the match checker, | ||
2021 | // so this acts as a regression test for that. | ||
2022 | check_diagnostic( | ||
2023 | r" | ||
2024 | pub enum Category { | ||
2025 | Infinity, | ||
2026 | Zero, | ||
2027 | } | ||
2028 | |||
2029 | fn panic(a: Category, b: Category) { | ||
2030 | match (a, b) { | ||
2031 | (Category::Infinity, Category::Infinity) | (Category::Zero, Category::Zero) => {} | ||
2032 | |||
2033 | (Category::Infinity | Category::Zero, _) => {} | ||
2034 | } | ||
2035 | } | ||
2036 | ", | ||
2037 | ); | ||
2038 | } | ||
2039 | } | ||
2040 | |||
2041 | #[cfg(test)] | ||
2042 | mod false_negatives { | ||
2043 | //! The implementation of match checking here is a work in progress. As we roll this out, we | ||
2044 | //! prefer false negatives to false positives (ideally there would be no false positives). This | ||
2045 | //! test module should document known false negatives. Eventually we will have a complete | ||
2046 | //! implementation of match checking and this module will be empty. | ||
2047 | //! | ||
2048 | //! The reasons for documenting known false negatives: | ||
2049 | //! | ||
2050 | //! 1. It acts as a backlog of work that can be done to improve the behavior of the system. | ||
2051 | //! 2. It ensures the code doesn't panic when handling these cases. | ||
2052 | |||
2053 | use super::tests::*; | ||
2054 | |||
2055 | #[test] | ||
2056 | fn integers() { | ||
2057 | // This is a false negative. | ||
2058 | // We don't currently check integer exhaustiveness. | ||
2059 | check_no_diagnostic( | ||
2060 | r" | ||
2061 | fn test_fn() { | ||
2062 | match 5 { | ||
2063 | 10 => (), | ||
2064 | 11..20 => (), | ||
2065 | } | ||
2066 | } | ||
2067 | ", | ||
2068 | ); | ||
2069 | } | ||
2070 | |||
2071 | #[test] | ||
2072 | fn internal_or() { | ||
2073 | // This is a false negative. | ||
2074 | // We do not currently handle patterns with internal `or`s. | ||
2075 | check_no_diagnostic( | ||
2076 | r" | ||
2077 | fn test_fn() { | ||
2078 | enum Either { | ||
2079 | A(bool), | ||
2080 | B, | ||
2081 | } | ||
2082 | match Either::B { | ||
2083 | Either::A(true | false) => (), | ||
2084 | } | ||
2085 | } | ||
2086 | ", | ||
2087 | ); | ||
2088 | } | ||
2089 | |||
2090 | #[test] | ||
2091 | fn expr_loop_missing_arm() { | ||
2092 | // This is a false negative. | ||
2093 | // We currently infer the type of `loop { break Foo::A }` to `!`, which | ||
2094 | // causes us to skip the diagnostic since `Either::A` doesn't type check | ||
2095 | // with `!`. | ||
2096 | check_diagnostic( | ||
2097 | r" | ||
2098 | enum Either { | ||
2099 | A, | ||
2100 | B, | ||
2101 | } | ||
2102 | fn test_fn() { | ||
2103 | match loop { break Foo::A } { | ||
2104 | Either::A => (), | ||
2105 | } | ||
2106 | } | ||
2107 | ", | ||
2108 | ); | ||
2109 | } | ||
2110 | |||
2111 | #[test] | ||
2112 | fn tuple_of_bools_with_ellipsis_at_end_missing_arm() { | ||
2113 | // This is a false negative. | ||
2114 | // We don't currently handle tuple patterns with ellipsis. | ||
2115 | check_no_diagnostic( | ||
2116 | r" | ||
2117 | fn test_fn() { | ||
2118 | match (false, true, false) { | ||
2119 | (false, ..) => {}, | ||
2120 | } | ||
2121 | } | ||
2122 | ", | ||
2123 | ); | ||
2124 | } | ||
2125 | |||
2126 | #[test] | ||
2127 | fn tuple_of_bools_with_ellipsis_at_beginning_missing_arm() { | ||
2128 | // This is a false negative. | ||
2129 | // We don't currently handle tuple patterns with ellipsis. | ||
2130 | check_no_diagnostic( | ||
2131 | r" | ||
2132 | fn test_fn() { | ||
2133 | match (false, true, false) { | ||
2134 | (.., false) => {}, | ||
2135 | } | ||
2136 | } | ||
2137 | ", | ||
2138 | ); | ||
2139 | } | ||
2140 | |||
2141 | #[test] | ||
2142 | fn struct_missing_arm() { | ||
2143 | // This is a false negative. | ||
2144 | // We don't currently handle structs. | ||
2145 | check_no_diagnostic( | ||
2146 | r" | ||
2147 | struct Foo { | ||
2148 | a: bool, | ||
2149 | } | ||
2150 | fn test_fn(f: Foo) { | ||
2151 | match f { | ||
2152 | Foo { a: true } => {}, | ||
2153 | } | ||
2154 | } | ||
2155 | ", | ||
2156 | ); | ||
2157 | } | ||
2158 | } | ||
diff --git a/crates/ra_hir_ty/src/diagnostics/unsafe_check.rs b/crates/ra_hir_ty/src/diagnostics/unsafe_check.rs new file mode 100644 index 000000000..b8ff95ee1 --- /dev/null +++ b/crates/ra_hir_ty/src/diagnostics/unsafe_check.rs | |||
@@ -0,0 +1,123 @@ | |||
1 | //! Provides validations for unsafe code. Currently checks if unsafe functions are missing | ||
2 | //! unsafe blocks. | ||
3 | |||
4 | use std::sync::Arc; | ||
5 | |||
6 | use hir_def::{ | ||
7 | body::Body, | ||
8 | expr::{Expr, ExprId, UnaryOp}, | ||
9 | DefWithBodyId, | ||
10 | }; | ||
11 | use hir_expand::diagnostics::DiagnosticSink; | ||
12 | |||
13 | use crate::{ | ||
14 | db::HirDatabase, diagnostics::MissingUnsafe, lower::CallableDef, ApplicationTy, | ||
15 | InferenceResult, Ty, TypeCtor, | ||
16 | }; | ||
17 | |||
18 | pub(super) struct UnsafeValidator<'a, 'b: 'a> { | ||
19 | owner: DefWithBodyId, | ||
20 | infer: Arc<InferenceResult>, | ||
21 | sink: &'a mut DiagnosticSink<'b>, | ||
22 | } | ||
23 | |||
24 | impl<'a, 'b> UnsafeValidator<'a, 'b> { | ||
25 | pub(super) fn new( | ||
26 | owner: DefWithBodyId, | ||
27 | infer: Arc<InferenceResult>, | ||
28 | sink: &'a mut DiagnosticSink<'b>, | ||
29 | ) -> UnsafeValidator<'a, 'b> { | ||
30 | UnsafeValidator { owner, infer, sink } | ||
31 | } | ||
32 | |||
33 | pub(super) fn validate_body(&mut self, db: &dyn HirDatabase) { | ||
34 | let def = self.owner.into(); | ||
35 | let unsafe_expressions = unsafe_expressions(db, self.infer.as_ref(), def); | ||
36 | let is_unsafe = match self.owner { | ||
37 | DefWithBodyId::FunctionId(it) => db.function_data(it).is_unsafe, | ||
38 | DefWithBodyId::StaticId(_) | DefWithBodyId::ConstId(_) => false, | ||
39 | }; | ||
40 | if is_unsafe | ||
41 | || unsafe_expressions | ||
42 | .iter() | ||
43 | .filter(|unsafe_expr| !unsafe_expr.inside_unsafe_block) | ||
44 | .count() | ||
45 | == 0 | ||
46 | { | ||
47 | return; | ||
48 | } | ||
49 | |||
50 | let (_, body_source) = db.body_with_source_map(def); | ||
51 | for unsafe_expr in unsafe_expressions { | ||
52 | if !unsafe_expr.inside_unsafe_block { | ||
53 | if let Ok(in_file) = body_source.as_ref().expr_syntax(unsafe_expr.expr) { | ||
54 | self.sink.push(MissingUnsafe { file: in_file.file_id, expr: in_file.value }) | ||
55 | } | ||
56 | } | ||
57 | } | ||
58 | } | ||
59 | } | ||
60 | |||
61 | pub struct UnsafeExpr { | ||
62 | pub expr: ExprId, | ||
63 | pub inside_unsafe_block: bool, | ||
64 | } | ||
65 | |||
66 | pub fn unsafe_expressions( | ||
67 | db: &dyn HirDatabase, | ||
68 | infer: &InferenceResult, | ||
69 | def: DefWithBodyId, | ||
70 | ) -> Vec<UnsafeExpr> { | ||
71 | let mut unsafe_exprs = vec![]; | ||
72 | let body = db.body(def); | ||
73 | walk_unsafe(&mut unsafe_exprs, db, infer, &body, body.body_expr, false); | ||
74 | |||
75 | unsafe_exprs | ||
76 | } | ||
77 | |||
78 | fn walk_unsafe( | ||
79 | unsafe_exprs: &mut Vec<UnsafeExpr>, | ||
80 | db: &dyn HirDatabase, | ||
81 | infer: &InferenceResult, | ||
82 | body: &Body, | ||
83 | current: ExprId, | ||
84 | inside_unsafe_block: bool, | ||
85 | ) { | ||
86 | let expr = &body.exprs[current]; | ||
87 | match expr { | ||
88 | Expr::Call { callee, .. } => { | ||
89 | let ty = &infer[*callee]; | ||
90 | if let &Ty::Apply(ApplicationTy { | ||
91 | ctor: TypeCtor::FnDef(CallableDef::FunctionId(func)), | ||
92 | .. | ||
93 | }) = ty | ||
94 | { | ||
95 | if db.function_data(func).is_unsafe { | ||
96 | unsafe_exprs.push(UnsafeExpr { expr: current, inside_unsafe_block }); | ||
97 | } | ||
98 | } | ||
99 | } | ||
100 | Expr::MethodCall { .. } => { | ||
101 | if infer | ||
102 | .method_resolution(current) | ||
103 | .map(|func| db.function_data(func).is_unsafe) | ||
104 | .unwrap_or(false) | ||
105 | { | ||
106 | unsafe_exprs.push(UnsafeExpr { expr: current, inside_unsafe_block }); | ||
107 | } | ||
108 | } | ||
109 | Expr::UnaryOp { expr, op: UnaryOp::Deref } => { | ||
110 | if let Ty::Apply(ApplicationTy { ctor: TypeCtor::RawPtr(..), .. }) = &infer[*expr] { | ||
111 | unsafe_exprs.push(UnsafeExpr { expr: current, inside_unsafe_block }); | ||
112 | } | ||
113 | } | ||
114 | Expr::Unsafe { body: child } => { | ||
115 | return walk_unsafe(unsafe_exprs, db, infer, body, *child, true); | ||
116 | } | ||
117 | _ => {} | ||
118 | } | ||
119 | |||
120 | expr.walk_child_exprs(|child| { | ||
121 | walk_unsafe(unsafe_exprs, db, infer, body, child, inside_unsafe_block); | ||
122 | }); | ||
123 | } | ||