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-rw-r--r--crates/ide_diagnostics/src/handlers/missing_match_arms.rs929
1 files changed, 929 insertions, 0 deletions
diff --git a/crates/ide_diagnostics/src/handlers/missing_match_arms.rs b/crates/ide_diagnostics/src/handlers/missing_match_arms.rs
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index 000000000..9ea533d74
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+++ b/crates/ide_diagnostics/src/handlers/missing_match_arms.rs
@@ -0,0 +1,929 @@
1use hir::InFile;
2
3use crate::{Diagnostic, DiagnosticsContext};
4
5// Diagnostic: missing-match-arm
6//
7// This diagnostic is triggered if `match` block is missing one or more match arms.
8pub(crate) fn missing_match_arms(
9 ctx: &DiagnosticsContext<'_>,
10 d: &hir::MissingMatchArms,
11) -> Diagnostic {
12 Diagnostic::new(
13 "missing-match-arm",
14 "missing match arm",
15 ctx.sema.diagnostics_display_range(InFile::new(d.file, d.match_expr.clone().into())).range,
16 )
17}
18
19#[cfg(test)]
20mod tests {
21 use crate::tests::check_diagnostics;
22
23 fn check_diagnostics_no_bails(ra_fixture: &str) {
24 cov_mark::check_count!(validate_match_bailed_out, 0);
25 crate::tests::check_diagnostics(ra_fixture)
26 }
27
28 #[test]
29 fn empty_tuple() {
30 check_diagnostics_no_bails(
31 r#"
32fn main() {
33 match () { }
34 //^^ missing match arm
35 match (()) { }
36 //^^^^ missing match arm
37
38 match () { _ => (), }
39 match () { () => (), }
40 match (()) { (()) => (), }
41}
42"#,
43 );
44 }
45
46 #[test]
47 fn tuple_of_two_empty_tuple() {
48 check_diagnostics_no_bails(
49 r#"
50fn main() {
51 match ((), ()) { }
52 //^^^^^^^^ missing match arm
53
54 match ((), ()) { ((), ()) => (), }
55}
56"#,
57 );
58 }
59
60 #[test]
61 fn boolean() {
62 check_diagnostics_no_bails(
63 r#"
64fn test_main() {
65 match false { }
66 //^^^^^ missing match arm
67 match false { true => (), }
68 //^^^^^ missing match arm
69 match (false, true) {}
70 //^^^^^^^^^^^^^ missing match arm
71 match (false, true) { (true, true) => (), }
72 //^^^^^^^^^^^^^ missing match arm
73 match (false, true) {
74 //^^^^^^^^^^^^^ missing match arm
75 (false, true) => (),
76 (false, false) => (),
77 (true, false) => (),
78 }
79 match (false, true) { (true, _x) => (), }
80 //^^^^^^^^^^^^^ missing match arm
81
82 match false { true => (), false => (), }
83 match (false, true) {
84 (false, _) => (),
85 (true, false) => (),
86 (_, true) => (),
87 }
88 match (false, true) {
89 (true, true) => (),
90 (true, false) => (),
91 (false, true) => (),
92 (false, false) => (),
93 }
94 match (false, true) {
95 (true, _x) => (),
96 (false, true) => (),
97 (false, false) => (),
98 }
99 match (false, true, false) {
100 (false, ..) => (),
101 (true, ..) => (),
102 }
103 match (false, true, false) {
104 (.., false) => (),
105 (.., true) => (),
106 }
107 match (false, true, false) { (..) => (), }
108}
109"#,
110 );
111 }
112
113 #[test]
114 fn tuple_of_tuple_and_bools() {
115 check_diagnostics_no_bails(
116 r#"
117fn main() {
118 match (false, ((), false)) {}
119 //^^^^^^^^^^^^^^^^^^^^ missing match arm
120 match (false, ((), false)) { (true, ((), true)) => (), }
121 //^^^^^^^^^^^^^^^^^^^^ missing match arm
122 match (false, ((), false)) { (true, _) => (), }
123 //^^^^^^^^^^^^^^^^^^^^ missing match arm
124
125 match (false, ((), false)) {
126 (true, ((), true)) => (),
127 (true, ((), false)) => (),
128 (false, ((), true)) => (),
129 (false, ((), false)) => (),
130 }
131 match (false, ((), false)) {
132 (true, ((), true)) => (),
133 (true, ((), false)) => (),
134 (false, _) => (),
135 }
136}
137"#,
138 );
139 }
140
141 #[test]
142 fn enums() {
143 check_diagnostics_no_bails(
144 r#"
145enum Either { A, B, }
146
147fn main() {
148 match Either::A { }
149 //^^^^^^^^^ missing match arm
150 match Either::B { Either::A => (), }
151 //^^^^^^^^^ missing match arm
152
153 match &Either::B {
154 //^^^^^^^^^^ missing match arm
155 Either::A => (),
156 }
157
158 match Either::B {
159 Either::A => (), Either::B => (),
160 }
161 match &Either::B {
162 Either::A => (), Either::B => (),
163 }
164}
165"#,
166 );
167 }
168
169 #[test]
170 fn enum_containing_bool() {
171 check_diagnostics_no_bails(
172 r#"
173enum Either { A(bool), B }
174
175fn main() {
176 match Either::B { }
177 //^^^^^^^^^ missing match arm
178 match Either::B {
179 //^^^^^^^^^ missing match arm
180 Either::A(true) => (), Either::B => ()
181 }
182
183 match Either::B {
184 Either::A(true) => (),
185 Either::A(false) => (),
186 Either::B => (),
187 }
188 match Either::B {
189 Either::B => (),
190 _ => (),
191 }
192 match Either::B {
193 Either::A(_) => (),
194 Either::B => (),
195 }
196
197}
198 "#,
199 );
200 }
201
202 #[test]
203 fn enum_different_sizes() {
204 check_diagnostics_no_bails(
205 r#"
206enum Either { A(bool), B(bool, bool) }
207
208fn main() {
209 match Either::A(false) {
210 //^^^^^^^^^^^^^^^^ missing match arm
211 Either::A(_) => (),
212 Either::B(false, _) => (),
213 }
214
215 match Either::A(false) {
216 Either::A(_) => (),
217 Either::B(true, _) => (),
218 Either::B(false, _) => (),
219 }
220 match Either::A(false) {
221 Either::A(true) | Either::A(false) => (),
222 Either::B(true, _) => (),
223 Either::B(false, _) => (),
224 }
225}
226"#,
227 );
228 }
229
230 #[test]
231 fn tuple_of_enum_no_diagnostic() {
232 check_diagnostics_no_bails(
233 r#"
234enum Either { A(bool), B(bool, bool) }
235enum Either2 { C, D }
236
237fn main() {
238 match (Either::A(false), Either2::C) {
239 (Either::A(true), _) | (Either::A(false), _) => (),
240 (Either::B(true, _), Either2::C) => (),
241 (Either::B(false, _), Either2::C) => (),
242 (Either::B(_, _), Either2::D) => (),
243 }
244}
245"#,
246 );
247 }
248
249 #[test]
250 fn or_pattern_no_diagnostic() {
251 check_diagnostics_no_bails(
252 r#"
253enum Either {A, B}
254
255fn main() {
256 match (Either::A, Either::B) {
257 (Either::A | Either::B, _) => (),
258 }
259}"#,
260 )
261 }
262
263 #[test]
264 fn mismatched_types() {
265 cov_mark::check_count!(validate_match_bailed_out, 4);
266 // Match statements with arms that don't match the
267 // expression pattern do not fire this diagnostic.
268 check_diagnostics(
269 r#"
270enum Either { A, B }
271enum Either2 { C, D }
272
273fn main() {
274 match Either::A {
275 Either2::C => (),
276 Either2::D => (),
277 }
278 match (true, false) {
279 (true, false, true) => (),
280 (true) => (),
281 }
282 match (true, false) { (true,) => {} }
283 match (0) { () => () }
284 match Unresolved::Bar { Unresolved::Baz => () }
285}
286 "#,
287 );
288 }
289
290 #[test]
291 fn mismatched_types_in_or_patterns() {
292 cov_mark::check_count!(validate_match_bailed_out, 2);
293 check_diagnostics(
294 r#"
295fn main() {
296 match false { true | () => {} }
297 match (false,) { (true | (),) => {} }
298}
299"#,
300 );
301 }
302
303 #[test]
304 fn malformed_match_arm_tuple_enum_missing_pattern() {
305 // We are testing to be sure we don't panic here when the match
306 // arm `Either::B` is missing its pattern.
307 check_diagnostics_no_bails(
308 r#"
309enum Either { A, B(u32) }
310
311fn main() {
312 match Either::A {
313 Either::A => (),
314 Either::B() => (),
315 }
316}
317"#,
318 );
319 }
320
321 #[test]
322 fn malformed_match_arm_extra_fields() {
323 cov_mark::check_count!(validate_match_bailed_out, 2);
324 check_diagnostics(
325 r#"
326enum A { B(isize, isize), C }
327fn main() {
328 match A::B(1, 2) {
329 A::B(_, _, _) => (),
330 }
331 match A::B(1, 2) {
332 A::C(_) => (),
333 }
334}
335"#,
336 );
337 }
338
339 #[test]
340 fn expr_diverges() {
341 cov_mark::check_count!(validate_match_bailed_out, 2);
342 check_diagnostics(
343 r#"
344enum Either { A, B }
345
346fn main() {
347 match loop {} {
348 Either::A => (),
349 Either::B => (),
350 }
351 match loop {} {
352 Either::A => (),
353 }
354 match loop { break Foo::A } {
355 //^^^^^^^^^^^^^^^^^^^^^ missing match arm
356 Either::A => (),
357 }
358 match loop { break Foo::A } {
359 Either::A => (),
360 Either::B => (),
361 }
362}
363"#,
364 );
365 }
366
367 #[test]
368 fn expr_partially_diverges() {
369 check_diagnostics_no_bails(
370 r#"
371enum Either<T> { A(T), B }
372
373fn foo() -> Either<!> { Either::B }
374fn main() -> u32 {
375 match foo() {
376 Either::A(val) => val,
377 Either::B => 0,
378 }
379}
380"#,
381 );
382 }
383
384 #[test]
385 fn enum_record() {
386 check_diagnostics_no_bails(
387 r#"
388enum Either { A { foo: bool }, B }
389
390fn main() {
391 let a = Either::A { foo: true };
392 match a { }
393 //^ missing match arm
394 match a { Either::A { foo: true } => () }
395 //^ missing match arm
396 match a {
397 Either::A { } => (),
398 //^^^^^^^^^ Missing structure fields:
399 // | - foo
400 Either::B => (),
401 }
402 match a {
403 //^ missing match arm
404 Either::A { } => (),
405 } //^^^^^^^^^ Missing structure fields:
406 // | - foo
407
408 match a {
409 Either::A { foo: true } => (),
410 Either::A { foo: false } => (),
411 Either::B => (),
412 }
413 match a {
414 Either::A { foo: _ } => (),
415 Either::B => (),
416 }
417}
418"#,
419 );
420 }
421
422 #[test]
423 fn enum_record_fields_out_of_order() {
424 check_diagnostics_no_bails(
425 r#"
426enum Either {
427 A { foo: bool, bar: () },
428 B,
429}
430
431fn main() {
432 let a = Either::A { foo: true, bar: () };
433 match a {
434 //^ missing match arm
435 Either::A { bar: (), foo: false } => (),
436 Either::A { foo: true, bar: () } => (),
437 }
438
439 match a {
440 Either::A { bar: (), foo: false } => (),
441 Either::A { foo: true, bar: () } => (),
442 Either::B => (),
443 }
444}
445"#,
446 );
447 }
448
449 #[test]
450 fn enum_record_ellipsis() {
451 check_diagnostics_no_bails(
452 r#"
453enum Either {
454 A { foo: bool, bar: bool },
455 B,
456}
457
458fn main() {
459 let a = Either::B;
460 match a {
461 //^ missing match arm
462 Either::A { foo: true, .. } => (),
463 Either::B => (),
464 }
465 match a {
466 //^ missing match arm
467 Either::A { .. } => (),
468 }
469
470 match a {
471 Either::A { foo: true, .. } => (),
472 Either::A { foo: false, .. } => (),
473 Either::B => (),
474 }
475
476 match a {
477 Either::A { .. } => (),
478 Either::B => (),
479 }
480}
481"#,
482 );
483 }
484
485 #[test]
486 fn enum_tuple_partial_ellipsis() {
487 check_diagnostics_no_bails(
488 r#"
489enum Either {
490 A(bool, bool, bool, bool),
491 B,
492}
493
494fn main() {
495 match Either::B {
496 //^^^^^^^^^ missing match arm
497 Either::A(true, .., true) => (),
498 Either::A(true, .., false) => (),
499 Either::A(false, .., false) => (),
500 Either::B => (),
501 }
502 match Either::B {
503 //^^^^^^^^^ missing match arm
504 Either::A(true, .., true) => (),
505 Either::A(true, .., false) => (),
506 Either::A(.., true) => (),
507 Either::B => (),
508 }
509
510 match Either::B {
511 Either::A(true, .., true) => (),
512 Either::A(true, .., false) => (),
513 Either::A(false, .., true) => (),
514 Either::A(false, .., false) => (),
515 Either::B => (),
516 }
517 match Either::B {
518 Either::A(true, .., true) => (),
519 Either::A(true, .., false) => (),
520 Either::A(.., true) => (),
521 Either::A(.., false) => (),
522 Either::B => (),
523 }
524}
525"#,
526 );
527 }
528
529 #[test]
530 fn never() {
531 check_diagnostics_no_bails(
532 r#"
533enum Never {}
534
535fn enum_(never: Never) {
536 match never {}
537}
538fn enum_ref(never: &Never) {
539 match never {}
540 //^^^^^ missing match arm
541}
542fn bang(never: !) {
543 match never {}
544}
545"#,
546 );
547 }
548
549 #[test]
550 fn unknown_type() {
551 cov_mark::check_count!(validate_match_bailed_out, 1);
552
553 check_diagnostics(
554 r#"
555enum Option<T> { Some(T), None }
556
557fn main() {
558 // `Never` is deliberately not defined so that it's an uninferred type.
559 match Option::<Never>::None {
560 None => (),
561 Some(never) => match never {},
562 }
563 match Option::<Never>::None {
564 //^^^^^^^^^^^^^^^^^^^^^ missing match arm
565 Option::Some(_never) => {},
566 }
567}
568"#,
569 );
570 }
571
572 #[test]
573 fn tuple_of_bools_with_ellipsis_at_end_missing_arm() {
574 check_diagnostics_no_bails(
575 r#"
576fn main() {
577 match (false, true, false) {
578 //^^^^^^^^^^^^^^^^^^^^ missing match arm
579 (false, ..) => (),
580 }
581}"#,
582 );
583 }
584
585 #[test]
586 fn tuple_of_bools_with_ellipsis_at_beginning_missing_arm() {
587 check_diagnostics_no_bails(
588 r#"
589fn main() {
590 match (false, true, false) {
591 //^^^^^^^^^^^^^^^^^^^^ missing match arm
592 (.., false) => (),
593 }
594}"#,
595 );
596 }
597
598 #[test]
599 fn tuple_of_bools_with_ellipsis_in_middle_missing_arm() {
600 check_diagnostics_no_bails(
601 r#"
602fn main() {
603 match (false, true, false) {
604 //^^^^^^^^^^^^^^^^^^^^ missing match arm
605 (true, .., false) => (),
606 }
607}"#,
608 );
609 }
610
611 #[test]
612 fn record_struct() {
613 check_diagnostics_no_bails(
614 r#"struct Foo { a: bool }
615fn main(f: Foo) {
616 match f {}
617 //^ missing match arm
618 match f { Foo { a: true } => () }
619 //^ missing match arm
620 match &f { Foo { a: true } => () }
621 //^^ missing match arm
622 match f { Foo { a: _ } => () }
623 match f {
624 Foo { a: true } => (),
625 Foo { a: false } => (),
626 }
627 match &f {
628 Foo { a: true } => (),
629 Foo { a: false } => (),
630 }
631}
632"#,
633 );
634 }
635
636 #[test]
637 fn tuple_struct() {
638 check_diagnostics_no_bails(
639 r#"struct Foo(bool);
640fn main(f: Foo) {
641 match f {}
642 //^ missing match arm
643 match f { Foo(true) => () }
644 //^ missing match arm
645 match f {
646 Foo(true) => (),
647 Foo(false) => (),
648 }
649}
650"#,
651 );
652 }
653
654 #[test]
655 fn unit_struct() {
656 check_diagnostics_no_bails(
657 r#"struct Foo;
658fn main(f: Foo) {
659 match f {}
660 //^ missing match arm
661 match f { Foo => () }
662}
663"#,
664 );
665 }
666
667 #[test]
668 fn record_struct_ellipsis() {
669 check_diagnostics_no_bails(
670 r#"struct Foo { foo: bool, bar: bool }
671fn main(f: Foo) {
672 match f { Foo { foo: true, .. } => () }
673 //^ missing match arm
674 match f {
675 //^ missing match arm
676 Foo { foo: true, .. } => (),
677 Foo { bar: false, .. } => ()
678 }
679 match f { Foo { .. } => () }
680 match f {
681 Foo { foo: true, .. } => (),
682 Foo { foo: false, .. } => ()
683 }
684}
685"#,
686 );
687 }
688
689 #[test]
690 fn internal_or() {
691 check_diagnostics_no_bails(
692 r#"
693fn main() {
694 enum Either { A(bool), B }
695 match Either::B {
696 //^^^^^^^^^ missing match arm
697 Either::A(true | false) => (),
698 }
699}
700"#,
701 );
702 }
703
704 #[test]
705 fn no_panic_at_unimplemented_subpattern_type() {
706 cov_mark::check_count!(validate_match_bailed_out, 1);
707
708 check_diagnostics(
709 r#"
710struct S { a: char}
711fn main(v: S) {
712 match v { S{ a } => {} }
713 match v { S{ a: _x } => {} }
714 match v { S{ a: 'a' } => {} }
715 match v { S{..} => {} }
716 match v { _ => {} }
717 match v { }
718 //^ missing match arm
719}
720"#,
721 );
722 }
723
724 #[test]
725 fn binding() {
726 check_diagnostics_no_bails(
727 r#"
728fn main() {
729 match true {
730 _x @ true => {}
731 false => {}
732 }
733 match true { _x @ true => {} }
734 //^^^^ missing match arm
735}
736"#,
737 );
738 }
739
740 #[test]
741 fn binding_ref_has_correct_type() {
742 cov_mark::check_count!(validate_match_bailed_out, 1);
743
744 // Asserts `PatKind::Binding(ref _x): bool`, not &bool.
745 // If that's not true match checking will panic with "incompatible constructors"
746 // FIXME: make facilities to test this directly like `tests::check_infer(..)`
747 check_diagnostics(
748 r#"
749enum Foo { A }
750fn main() {
751 // FIXME: this should not bail out but current behavior is such as the old algorithm.
752 // ExprValidator::validate_match(..) checks types of top level patterns incorrecly.
753 match Foo::A {
754 ref _x => {}
755 Foo::A => {}
756 }
757 match (true,) {
758 (ref _x,) => {}
759 (true,) => {}
760 }
761}
762"#,
763 );
764 }
765
766 #[test]
767 fn enum_non_exhaustive() {
768 check_diagnostics_no_bails(
769 r#"
770//- /lib.rs crate:lib
771#[non_exhaustive]
772pub enum E { A, B }
773fn _local() {
774 match E::A { _ => {} }
775 match E::A {
776 E::A => {}
777 E::B => {}
778 }
779 match E::A {
780 E::A | E::B => {}
781 }
782}
783
784//- /main.rs crate:main deps:lib
785use lib::E;
786fn main() {
787 match E::A { _ => {} }
788 match E::A {
789 //^^^^ missing match arm
790 E::A => {}
791 E::B => {}
792 }
793 match E::A {
794 //^^^^ missing match arm
795 E::A | E::B => {}
796 }
797}
798"#,
799 );
800 }
801
802 #[test]
803 fn match_guard() {
804 check_diagnostics_no_bails(
805 r#"
806fn main() {
807 match true {
808 true if false => {}
809 true => {}
810 false => {}
811 }
812 match true {
813 //^^^^ missing match arm
814 true if false => {}
815 false => {}
816 }
817}
818"#,
819 );
820 }
821
822 #[test]
823 fn pattern_type_is_of_substitution() {
824 cov_mark::check!(match_check_wildcard_expanded_to_substitutions);
825 check_diagnostics_no_bails(
826 r#"
827struct Foo<T>(T);
828struct Bar;
829fn main() {
830 match Foo(Bar) {
831 _ | Foo(Bar) => {}
832 }
833}
834"#,
835 );
836 }
837
838 #[test]
839 fn record_struct_no_such_field() {
840 cov_mark::check_count!(validate_match_bailed_out, 1);
841
842 check_diagnostics(
843 r#"
844struct Foo { }
845fn main(f: Foo) {
846 match f { Foo { bar } => () }
847}
848"#,
849 );
850 }
851
852 #[test]
853 fn match_ergonomics_issue_9095() {
854 check_diagnostics_no_bails(
855 r#"
856enum Foo<T> { A(T) }
857fn main() {
858 match &Foo::A(true) {
859 _ => {}
860 Foo::A(_) => {}
861 }
862}
863"#,
864 );
865 }
866
867 mod false_negatives {
868 //! The implementation of match checking here is a work in progress. As we roll this out, we
869 //! prefer false negatives to false positives (ideally there would be no false positives). This
870 //! test module should document known false negatives. Eventually we will have a complete
871 //! implementation of match checking and this module will be empty.
872 //!
873 //! The reasons for documenting known false negatives:
874 //!
875 //! 1. It acts as a backlog of work that can be done to improve the behavior of the system.
876 //! 2. It ensures the code doesn't panic when handling these cases.
877 use super::*;
878
879 #[test]
880 fn integers() {
881 cov_mark::check_count!(validate_match_bailed_out, 1);
882
883 // We don't currently check integer exhaustiveness.
884 check_diagnostics(
885 r#"
886fn main() {
887 match 5 {
888 10 => (),
889 11..20 => (),
890 }
891}
892"#,
893 );
894 }
895
896 #[test]
897 fn reference_patterns_at_top_level() {
898 cov_mark::check_count!(validate_match_bailed_out, 1);
899
900 check_diagnostics(
901 r#"
902fn main() {
903 match &false {
904 &true => {}
905 }
906}
907 "#,
908 );
909 }
910
911 #[test]
912 fn reference_patterns_in_fields() {
913 cov_mark::check_count!(validate_match_bailed_out, 2);
914
915 check_diagnostics(
916 r#"
917fn main() {
918 match (&false,) {
919 (true,) => {}
920 }
921 match (&false,) {
922 (&true,) => {}
923 }
924}
925 "#,
926 );
927 }
928 }
929}