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authorJonas Schievink <[email protected]>2020-06-17 20:41:07 +0100
committerJonas Schievink <[email protected]>2020-06-17 20:41:07 +0100
commit4d6d7aec50e81d2d6da01e4f4fc1353430e79067 (patch)
treeb5192e25fd56dbfc3c289a5d117b1e0d5c8622ba /crates
parent1ce8c2b5a08949e78de7ff9dfbae594f6c17b951 (diff)
Avoid all unchecked indexing in match checking
Diffstat (limited to 'crates')
-rw-r--r--crates/ra_hir_ty/src/_match.rs77
1 files changed, 49 insertions, 28 deletions
diff --git a/crates/ra_hir_ty/src/_match.rs b/crates/ra_hir_ty/src/_match.rs
index 02a7a61f1..5495ce284 100644
--- a/crates/ra_hir_ty/src/_match.rs
+++ b/crates/ra_hir_ty/src/_match.rs
@@ -312,20 +312,16 @@ impl PatStack {
312 Self(v) 312 Self(v)
313 } 313 }
314 314
315 fn is_empty(&self) -> bool {
316 self.0.is_empty()
317 }
318
319 fn head(&self) -> PatIdOrWild {
320 self.0[0]
321 }
322
323 fn get_head(&self) -> Option<PatIdOrWild> { 315 fn get_head(&self) -> Option<PatIdOrWild> {
324 self.0.first().copied() 316 self.0.first().copied()
325 } 317 }
326 318
319 fn tail(&self) -> &[PatIdOrWild] {
320 self.0.get(1..).unwrap_or(&[])
321 }
322
327 fn to_tail(&self) -> PatStack { 323 fn to_tail(&self) -> PatStack {
328 Self::from_slice(&self.0[1..]) 324 Self::from_slice(self.tail())
329 } 325 }
330 326
331 fn replace_head_with<I, T>(&self, pats: I) -> PatStack 327 fn replace_head_with<I, T>(&self, pats: I) -> PatStack
@@ -347,7 +343,7 @@ impl PatStack {
347 /// 343 ///
348 /// See the module docs and the associated documentation in rustc for details. 344 /// See the module docs and the associated documentation in rustc for details.
349 fn specialize_wildcard(&self, cx: &MatchCheckCtx) -> Option<PatStack> { 345 fn specialize_wildcard(&self, cx: &MatchCheckCtx) -> Option<PatStack> {
350 if matches!(self.head().as_pat(cx), Pat::Wild) { 346 if matches!(self.get_head()?.as_pat(cx), Pat::Wild) {
351 Some(self.to_tail()) 347 Some(self.to_tail())
352 } else { 348 } else {
353 None 349 None
@@ -362,11 +358,12 @@ impl PatStack {
362 cx: &MatchCheckCtx, 358 cx: &MatchCheckCtx,
363 constructor: &Constructor, 359 constructor: &Constructor,
364 ) -> MatchCheckResult<Option<PatStack>> { 360 ) -> MatchCheckResult<Option<PatStack>> {
365 if self.is_empty() { 361 let head = match self.get_head() {
366 return Ok(None); 362 Some(head) => head,
367 } 363 None => return Ok(None),
364 };
368 365
369 let head_pat = self.head().as_pat(cx); 366 let head_pat = head.as_pat(cx);
370 let result = match (head_pat, constructor) { 367 let result = match (head_pat, constructor) {
371 (Pat::Tuple { args: ref pat_ids, ellipsis }, Constructor::Tuple { arity: _ }) => { 368 (Pat::Tuple { args: ref pat_ids, ellipsis }, Constructor::Tuple { arity: _ }) => {
372 if ellipsis.is_some() { 369 if ellipsis.is_some() {
@@ -394,7 +391,7 @@ impl PatStack {
394 (Pat::Wild, constructor) => Some(self.expand_wildcard(cx, constructor)?), 391 (Pat::Wild, constructor) => Some(self.expand_wildcard(cx, constructor)?),
395 (Pat::Path(_), Constructor::Enum(constructor)) => { 392 (Pat::Path(_), Constructor::Enum(constructor)) => {
396 // unit enum variants become `Pat::Path` 393 // unit enum variants become `Pat::Path`
397 let pat_id = self.head().as_id().expect("we know this isn't a wild"); 394 let pat_id = head.as_id().expect("we know this isn't a wild");
398 if !enum_variant_matches(cx, pat_id, *constructor) { 395 if !enum_variant_matches(cx, pat_id, *constructor) {
399 None 396 None
400 } else { 397 } else {
@@ -405,7 +402,7 @@ impl PatStack {
405 Pat::TupleStruct { args: ref pat_ids, ellipsis, .. }, 402 Pat::TupleStruct { args: ref pat_ids, ellipsis, .. },
406 Constructor::Enum(enum_constructor), 403 Constructor::Enum(enum_constructor),
407 ) => { 404 ) => {
408 let pat_id = self.head().as_id().expect("we know this isn't a wild"); 405 let pat_id = head.as_id().expect("we know this isn't a wild");
409 if !enum_variant_matches(cx, pat_id, *enum_constructor) { 406 if !enum_variant_matches(cx, pat_id, *enum_constructor) {
410 None 407 None
411 } else { 408 } else {
@@ -445,7 +442,7 @@ impl PatStack {
445 } 442 }
446 } 443 }
447 (Pat::Record { args: ref arg_patterns, .. }, Constructor::Enum(e)) => { 444 (Pat::Record { args: ref arg_patterns, .. }, Constructor::Enum(e)) => {
448 let pat_id = self.head().as_id().expect("we know this isn't a wild"); 445 let pat_id = head.as_id().expect("we know this isn't a wild");
449 if !enum_variant_matches(cx, pat_id, *e) { 446 if !enum_variant_matches(cx, pat_id, *e) {
450 None 447 None
451 } else { 448 } else {
@@ -491,7 +488,7 @@ impl PatStack {
491 ) -> MatchCheckResult<PatStack> { 488 ) -> MatchCheckResult<PatStack> {
492 assert_eq!( 489 assert_eq!(
493 Pat::Wild, 490 Pat::Wild,
494 self.head().as_pat(cx), 491 self.get_head().expect("expand_wildcard called on empty PatStack").as_pat(cx),
495 "expand_wildcard must only be called on PatStack with wild at head", 492 "expand_wildcard must only be called on PatStack with wild at head",
496 ); 493 );
497 494
@@ -509,7 +506,6 @@ impl PatStack {
509 } 506 }
510} 507}
511 508
512#[derive(Debug)]
513/// A collection of PatStack. 509/// A collection of PatStack.
514/// 510///
515/// This type is modeled from the struct of the same name in `rustc`. 511/// This type is modeled from the struct of the same name in `rustc`.
@@ -623,13 +619,16 @@ pub(crate) fn is_useful(
623 _ => (), 619 _ => (),
624 } 620 }
625 621
626 if v.is_empty() { 622 let head = match v.get_head() {
627 let result = if matrix.is_empty() { Usefulness::Useful } else { Usefulness::NotUseful }; 623 Some(head) => head,
624 None => {
625 let result = if matrix.is_empty() { Usefulness::Useful } else { Usefulness::NotUseful };
628 626
629 return Ok(result); 627 return Ok(result);
630 } 628 }
629 };
631 630
632 if let Pat::Or(pat_ids) = v.head().as_pat(cx) { 631 if let Pat::Or(pat_ids) = head.as_pat(cx) {
633 let mut found_unimplemented = false; 632 let mut found_unimplemented = false;
634 let any_useful = pat_ids.iter().any(|&pat_id| { 633 let any_useful = pat_ids.iter().any(|&pat_id| {
635 let v = PatStack::from_pattern(pat_id); 634 let v = PatStack::from_pattern(pat_id);
@@ -653,7 +652,7 @@ pub(crate) fn is_useful(
653 }; 652 };
654 } 653 }
655 654
656 if let Some(constructor) = pat_constructor(cx, v.head())? { 655 if let Some(constructor) = pat_constructor(cx, head)? {
657 let matrix = matrix.specialize_constructor(&cx, &constructor)?; 656 let matrix = matrix.specialize_constructor(&cx, &constructor)?;
658 let v = v 657 let v = v
659 .specialize_constructor(&cx, &constructor)? 658 .specialize_constructor(&cx, &constructor)?
@@ -854,10 +853,10 @@ mod tests {
854 } 853 }
855 854
856 pub(super) fn check_no_diagnostic(ra_fixture: &str) { 855 pub(super) fn check_no_diagnostic(ra_fixture: &str) {
857 let diagnostic_count = 856 let (s, diagnostic_count) =
858 TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>().1; 857 TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>();
859 858
860 assert_eq!(0, diagnostic_count, "expected no diagnostic, found one"); 859 assert_eq!(0, diagnostic_count, "expected no diagnostic, found one: {}", s);
861 } 860 }
862 861
863 #[test] 862 #[test]
@@ -2014,6 +2013,28 @@ mod tests {
2014 ", 2013 ",
2015 ); 2014 );
2016 } 2015 }
2016
2017 #[test]
2018 fn or_pattern_panic_2() {
2019 // FIXME: This is a false positive, but the code used to cause a panic in the match checker,
2020 // so this acts as a regression test for that.
2021 check_diagnostic(
2022 r"
2023 pub enum Category {
2024 Infinity,
2025 Zero,
2026 }
2027
2028 fn panic(a: Category, b: Category) {
2029 match (a, b) {
2030 (Category::Infinity, Category::Infinity) | (Category::Zero, Category::Zero) => {}
2031
2032 (Category::Infinity | Category::Zero, _) => {}
2033 }
2034 }
2035 ",
2036 );
2037 }
2017} 2038}
2018 2039
2019#[cfg(test)] 2040#[cfg(test)]