3 // After candidates have been simplified, the only match pairs that
4 // remain are those that require some sort of test. The functions here
5 // identify what tests are needed, perform the tests, and then filter
6 // the candidates based on the result.
8 use crate::build
::matches
::{Candidate, MatchPair, Test, TestKind}
;
9 use crate::build
::Builder
;
10 use crate::thir
::pattern
::compare_const_vals
;
12 use rustc_data_structures
::fx
::FxIndexMap
;
13 use rustc_hir
::{LangItem, RangeEnd}
;
14 use rustc_index
::bit_set
::BitSet
;
15 use rustc_middle
::mir
::*;
16 use rustc_middle
::ty
::util
::IntTypeExt
;
17 use rustc_middle
::ty
::{self, adjustment::PointerCast, Ty}
;
18 use rustc_span
::symbol
::sym
;
19 use rustc_target
::abi
::VariantIdx
;
21 use std
::cmp
::Ordering
;
23 impl<'a
, 'tcx
> Builder
<'a
, 'tcx
> {
24 /// Identifies what test is needed to decide if `match_pair` is applicable.
26 /// It is a bug to call this with a simplifiable pattern.
27 pub(super) fn test
<'pat
>(&mut self, match_pair
: &MatchPair
<'pat
, 'tcx
>) -> Test
<'tcx
> {
28 match *match_pair
.pattern
.kind
{
29 PatKind
::Variant { ref adt_def, substs: _, variant_index: _, subpatterns: _ }
=> Test
{
30 span
: match_pair
.pattern
.span
,
31 kind
: TestKind
::Switch
{
33 variants
: BitSet
::new_empty(adt_def
.variants
.len()),
37 PatKind
::Constant { .. }
if is_switch_ty(match_pair
.pattern
.ty
) => {
38 // For integers, we use a `SwitchInt` match, which allows
39 // us to handle more cases.
41 span
: match_pair
.pattern
.span
,
42 kind
: TestKind
::SwitchInt
{
43 switch_ty
: match_pair
.pattern
.ty
,
45 // these maps are empty to start; cases are
46 // added below in add_cases_to_switch
47 options
: Default
::default(),
52 PatKind
::Constant { value }
=> Test
{
53 span
: match_pair
.pattern
.span
,
54 kind
: TestKind
::Eq { value, ty: match_pair.pattern.ty.clone() }
,
57 PatKind
::Range(range
) => {
58 assert_eq
!(range
.lo
.ty
, match_pair
.pattern
.ty
);
59 assert_eq
!(range
.hi
.ty
, match_pair
.pattern
.ty
);
60 Test { span: match_pair.pattern.span, kind: TestKind::Range(range) }
63 PatKind
::Slice { ref prefix, ref slice, ref suffix }
=> {
64 let len
= prefix
.len() + suffix
.len();
65 let op
= if slice
.is_some() { BinOp::Ge }
else { BinOp::Eq }
;
66 Test { span: match_pair.pattern.span, kind: TestKind::Len { len: len as u64, op }
}
69 PatKind
::Or { .. }
=> bug
!("or-patterns should have already been handled"),
71 PatKind
::AscribeUserType { .. }
72 | PatKind
::Array { .. }
74 | PatKind
::Binding { .. }
75 | PatKind
::Leaf { .. }
76 | PatKind
::Deref { .. }
=> self.error_simplifyable(match_pair
),
80 pub(super) fn add_cases_to_switch
<'pat
>(
82 test_place
: &Place
<'tcx
>,
83 candidate
: &Candidate
<'pat
, 'tcx
>,
85 options
: &mut FxIndexMap
<&'tcx ty
::Const
<'tcx
>, u128
>,
87 let match_pair
= match candidate
.match_pairs
.iter().find(|mp
| mp
.place
== *test_place
) {
88 Some(match_pair
) => match_pair
,
94 match *match_pair
.pattern
.kind
{
95 PatKind
::Constant { value }
=> {
96 options
.entry(value
).or_insert_with(|| {
97 value
.eval_bits(self.hir
.tcx(), self.hir
.param_env
, switch_ty
)
101 PatKind
::Variant { .. }
=> {
102 panic
!("you should have called add_variants_to_switch instead!");
104 PatKind
::Range(range
) => {
105 // Check that none of the switch values are in the range.
106 self.values_not_contained_in_range(range
, options
).unwrap_or(false)
108 PatKind
::Slice { .. }
109 | PatKind
::Array { .. }
112 | PatKind
::Binding { .. }
113 | PatKind
::AscribeUserType { .. }
114 | PatKind
::Leaf { .. }
115 | PatKind
::Deref { .. }
=> {
116 // don't know how to add these patterns to a switch
122 pub(super) fn add_variants_to_switch
<'pat
>(
124 test_place
: &Place
<'tcx
>,
125 candidate
: &Candidate
<'pat
, 'tcx
>,
126 variants
: &mut BitSet
<VariantIdx
>,
128 let match_pair
= match candidate
.match_pairs
.iter().find(|mp
| mp
.place
== *test_place
) {
129 Some(match_pair
) => match_pair
,
135 match *match_pair
.pattern
.kind
{
136 PatKind
::Variant { adt_def: _, variant_index, .. }
=> {
137 // We have a pattern testing for variant `variant_index`
138 // set the corresponding index to true
139 variants
.insert(variant_index
);
143 // don't know how to add these patterns to a switch
149 pub(super) fn perform_test(
154 make_target_blocks
: impl FnOnce(&mut Self) -> Vec
<BasicBlock
>,
157 "perform_test({:?}, {:?}: {:?}, {:?})",
160 place
.ty(&self.local_decls
, self.hir
.tcx()),
164 let source_info
= self.source_info(test
.span
);
166 TestKind
::Switch { adt_def, ref variants }
=> {
167 let target_blocks
= make_target_blocks(self);
168 // Variants is a BitVec of indexes into adt_def.variants.
169 let num_enum_variants
= adt_def
.variants
.len();
170 debug_assert_eq
!(target_blocks
.len(), num_enum_variants
+ 1);
171 let otherwise_block
= *target_blocks
.last().unwrap();
172 let tcx
= self.hir
.tcx();
173 let switch_targets
= SwitchTargets
::new(
174 adt_def
.discriminants(tcx
).filter_map(|(idx
, discr
)| {
175 if variants
.contains(idx
) {
177 target_blocks
[idx
.index()],
179 "no canididates for tested discriminant: {:?}",
182 Some((discr
.val
, target_blocks
[idx
.index()]))
185 target_blocks
[idx
.index()],
187 "found canididates for untested discriminant: {:?}",
195 debug
!("num_enum_variants: {}, variants: {:?}", num_enum_variants
, variants
);
196 let discr_ty
= adt_def
.repr
.discr_type().to_ty(tcx
);
197 let discr
= self.temp(discr_ty
, test
.span
);
198 self.cfg
.push_assign(block
, source_info
, discr
, Rvalue
::Discriminant(place
));
202 TerminatorKind
::SwitchInt
{
203 discr
: Operand
::Move(discr
),
205 targets
: switch_targets
,
210 TestKind
::SwitchInt { switch_ty, ref options }
=> {
211 let target_blocks
= make_target_blocks(self);
212 let terminator
= if *switch_ty
.kind() == ty
::Bool
{
213 assert
!(!options
.is_empty() && options
.len() <= 2);
214 if let [first_bb
, second_bb
] = *target_blocks
{
215 let (true_bb
, false_bb
) = match options
[0] {
216 1 => (first_bb
, second_bb
),
217 0 => (second_bb
, first_bb
),
218 v
=> span_bug
!(test
.span
, "expected boolean value but got {:?}", v
),
220 TerminatorKind
::if_(self.hir
.tcx(), Operand
::Copy(place
), true_bb
, false_bb
)
222 bug
!("`TestKind::SwitchInt` on `bool` should have two targets")
225 // The switch may be inexhaustive so we have a catch all block
226 debug_assert_eq
!(options
.len() + 1, target_blocks
.len());
227 let otherwise_block
= *target_blocks
.last().unwrap();
228 let switch_targets
= SwitchTargets
::new(
229 options
.values().copied().zip(target_blocks
),
232 TerminatorKind
::SwitchInt
{
233 discr
: Operand
::Copy(place
),
235 targets
: switch_targets
,
238 self.cfg
.terminate(block
, source_info
, terminator
);
241 TestKind
::Eq { value, ty }
=> {
243 // Use `PartialEq::eq` instead of `BinOp::Eq`
244 // (the binop can only handle primitives)
245 self.non_scalar_compare(
253 } else if let [success
, fail
] = *make_target_blocks(self) {
254 assert_eq
!(value
.ty
, ty
);
255 let expect
= self.literal_operand(test
.span
, value
);
256 let val
= Operand
::Copy(place
);
257 self.compare(block
, success
, fail
, source_info
, BinOp
::Eq
, expect
, val
);
259 bug
!("`TestKind::Eq` should have two target blocks");
263 TestKind
::Range(PatRange { ref lo, ref hi, ref end }
) => {
264 let lower_bound_success
= self.cfg
.start_new_block();
265 let target_blocks
= make_target_blocks(self);
267 // Test `val` by computing `lo <= val && val <= hi`, using primitive comparisons.
268 let lo
= self.literal_operand(test
.span
, lo
);
269 let hi
= self.literal_operand(test
.span
, hi
);
270 let val
= Operand
::Copy(place
);
272 if let [success
, fail
] = *target_blocks
{
282 let op
= match *end
{
283 RangeEnd
::Included
=> BinOp
::Le
,
284 RangeEnd
::Excluded
=> BinOp
::Lt
,
286 self.compare(lower_bound_success
, success
, fail
, source_info
, op
, val
, hi
);
288 bug
!("`TestKind::Range` should have two target blocks");
292 TestKind
::Len { len, op }
=> {
293 let target_blocks
= make_target_blocks(self);
295 let usize_ty
= self.hir
.usize_ty();
296 let actual
= self.temp(usize_ty
, test
.span
);
298 // actual = len(place)
299 self.cfg
.push_assign(block
, source_info
, actual
, Rvalue
::Len(place
));
302 let expected
= self.push_usize(block
, source_info
, len
);
304 if let [true_bb
, false_bb
] = *target_blocks
{
305 // result = actual == expected OR result = actual < expected
306 // branch based on result
313 Operand
::Move(actual
),
314 Operand
::Move(expected
),
317 bug
!("`TestKind::Len` should have two target blocks");
323 /// Compare using the provided built-in comparison operator
327 success_block
: BasicBlock
,
328 fail_block
: BasicBlock
,
329 source_info
: SourceInfo
,
332 right
: Operand
<'tcx
>,
334 let bool_ty
= self.hir
.bool_ty();
335 let result
= self.temp(bool_ty
, source_info
.span
);
337 // result = op(left, right)
338 self.cfg
.push_assign(block
, source_info
, result
, Rvalue
::BinaryOp(op
, left
, right
));
340 // branch based on result
344 TerminatorKind
::if_(self.hir
.tcx(), Operand
::Move(result
), success_block
, fail_block
),
348 /// Compare two `&T` values using `<T as std::compare::PartialEq>::eq`
349 fn non_scalar_compare(
352 make_target_blocks
: impl FnOnce(&mut Self) -> Vec
<BasicBlock
>,
353 source_info
: SourceInfo
,
354 value
: &'tcx ty
::Const
<'tcx
>,
358 let mut expect
= self.literal_operand(source_info
.span
, value
);
359 let mut val
= Operand
::Copy(place
);
361 // If we're using `b"..."` as a pattern, we need to insert an
362 // unsizing coercion, as the byte string has the type `&[u8; N]`.
364 // We want to do this even when the scrutinee is a reference to an
365 // array, so we can call `<[u8]>::eq` rather than having to find an
367 let unsize
= |ty
: Ty
<'tcx
>| match ty
.kind() {
368 ty
::Ref(region
, rty
, _
) => match rty
.kind() {
369 ty
::Array(inner_ty
, n
) => Some((region
, inner_ty
, n
)),
374 let opt_ref_ty
= unsize(ty
);
375 let opt_ref_test_ty
= unsize(value
.ty
);
376 match (opt_ref_ty
, opt_ref_test_ty
) {
377 // nothing to do, neither is an array
379 (Some((region
, elem_ty
, _
)), _
) | (None
, Some((region
, elem_ty
, _
))) => {
380 let tcx
= self.hir
.tcx();
382 ty
= tcx
.mk_imm_ref(region
, tcx
.mk_slice(elem_ty
));
383 if opt_ref_ty
.is_some() {
384 let temp
= self.temp(ty
, source_info
.span
);
385 self.cfg
.push_assign(
389 Rvalue
::Cast(CastKind
::Pointer(PointerCast
::Unsize
), val
, ty
),
391 val
= Operand
::Move(temp
);
393 if opt_ref_test_ty
.is_some() {
394 let slice
= self.temp(ty
, source_info
.span
);
395 self.cfg
.push_assign(
399 Rvalue
::Cast(CastKind
::Pointer(PointerCast
::Unsize
), expect
, ty
),
401 expect
= Operand
::Move(slice
);
406 let deref_ty
= match *ty
.kind() {
407 ty
::Ref(_
, deref_ty
, _
) => deref_ty
,
408 _
=> bug
!("non_scalar_compare called on non-reference type: {}", ty
),
411 let eq_def_id
= self.hir
.tcx().require_lang_item(LangItem
::PartialEq
, None
);
412 let method
= self.hir
.trait_method(eq_def_id
, sym
::eq
, deref_ty
, &[deref_ty
.into()]);
414 let bool_ty
= self.hir
.bool_ty();
415 let eq_result
= self.temp(bool_ty
, source_info
.span
);
416 let eq_block
= self.cfg
.start_new_block();
420 TerminatorKind
::Call
{
421 func
: Operand
::Constant(box Constant
{
422 span
: source_info
.span
,
424 // FIXME(#54571): This constant comes from user input (a
425 // constant in a pattern). Are there forms where users can add
426 // type annotations here? For example, an associated constant?
427 // Need to experiment.
432 args
: vec
![val
, expect
],
433 destination
: Some((eq_result
, eq_block
)),
435 from_hir_call
: false,
436 fn_span
: source_info
.span
,
439 self.diverge_from(block
);
441 if let [success_block
, fail_block
] = *make_target_blocks(self) {
448 Operand
::Move(eq_result
),
454 bug
!("`TestKind::Eq` should have two target blocks")
458 /// Given that we are performing `test` against `test_place`, this job
459 /// sorts out what the status of `candidate` will be after the test. See
460 /// `test_candidates` for the usage of this function. The returned index is
461 /// the index that this candidate should be placed in the
462 /// `target_candidates` vec. The candidate may be modified to update its
465 /// So, for example, if this candidate is `x @ Some(P0)` and the `Test` is
466 /// a variant test, then we would modify the candidate to be `(x as
467 /// Option).0 @ P0` and return the index corresponding to the variant
470 /// However, in some cases, the test may just not be relevant to candidate.
471 /// For example, suppose we are testing whether `foo.x == 22`, but in one
472 /// match arm we have `Foo { x: _, ... }`... in that case, the test for
473 /// what value `x` has has no particular relevance to this candidate. In
474 /// such cases, this function just returns None without doing anything.
475 /// This is used by the overall `match_candidates` algorithm to structure
476 /// the match as a whole. See `match_candidates` for more details.
478 /// FIXME(#29623). In some cases, we have some tricky choices to make. for
479 /// example, if we are testing that `x == 22`, but the candidate is `x @
480 /// 13..55`, what should we do? In the event that the test is true, we know
481 /// that the candidate applies, but in the event of false, we don't know
482 /// that it *doesn't* apply. For now, we return false, indicate that the
483 /// test does not apply to this candidate, but it might be we can get
484 /// tighter match code if we do something a bit different.
485 pub(super) fn sort_candidate
<'pat
>(
487 test_place
: &Place
<'tcx
>,
489 candidate
: &mut Candidate
<'pat
, 'tcx
>,
491 // Find the match_pair for this place (if any). At present,
492 // afaik, there can be at most one. (In the future, if we
493 // adopted a more general `@` operator, there might be more
494 // than one, but it'd be very unusual to have two sides that
495 // both require tests; you'd expect one side to be simplified
497 let (match_pair_index
, match_pair
) =
498 candidate
.match_pairs
.iter().enumerate().find(|&(_
, mp
)| mp
.place
== *test_place
)?
;
500 match (&test
.kind
, &*match_pair
.pattern
.kind
) {
501 // If we are performing a variant switch, then this
502 // informs variant patterns, but nothing else.
504 &TestKind
::Switch { adt_def: tested_adt_def, .. }
,
505 &PatKind
::Variant { adt_def, variant_index, ref subpatterns, .. }
,
507 assert_eq
!(adt_def
, tested_adt_def
);
508 self.candidate_after_variant_switch(
515 Some(variant_index
.as_usize())
518 (&TestKind
::Switch { .. }
, _
) => None
,
520 // If we are performing a switch over integers, then this informs integer
521 // equality, but nothing else.
523 // FIXME(#29623) we could use PatKind::Range to rule
524 // things out here, in some cases.
526 &TestKind
::SwitchInt { switch_ty: _, ref options }
,
527 &PatKind
::Constant { ref value }
,
528 ) if is_switch_ty(match_pair
.pattern
.ty
) => {
529 let index
= options
.get_index_of(value
).unwrap();
530 self.candidate_without_match_pair(match_pair_index
, candidate
);
534 (&TestKind
::SwitchInt { switch_ty: _, ref options }
, &PatKind
::Range(range
)) => {
536 self.values_not_contained_in_range(range
, options
).unwrap_or(false);
539 // No switch values are contained in the pattern range,
540 // so the pattern can be matched only if this test fails.
541 let otherwise
= options
.len();
548 (&TestKind
::SwitchInt { .. }
, _
) => None
,
551 &TestKind
::Len { len: test_len, op: BinOp::Eq }
,
552 &PatKind
::Slice { ref prefix, ref slice, ref suffix }
,
554 let pat_len
= (prefix
.len() + suffix
.len()) as u64;
555 match (test_len
.cmp(&pat_len
), slice
) {
556 (Ordering
::Equal
, &None
) => {
557 // on true, min_len = len = $actual_length,
558 // on false, len != $actual_length
559 self.candidate_after_slice_test(
568 (Ordering
::Less
, _
) => {
569 // test_len < pat_len. If $actual_len = test_len,
570 // then $actual_len < pat_len and we don't have
574 (Ordering
::Equal
| Ordering
::Greater
, &Some(_
)) => {
575 // This can match both if $actual_len = test_len >= pat_len,
576 // and if $actual_len > test_len. We can't advance.
579 (Ordering
::Greater
, &None
) => {
580 // test_len != pat_len, so if $actual_len = test_len, then
581 // $actual_len != pat_len.
588 &TestKind
::Len { len: test_len, op: BinOp::Ge }
,
589 &PatKind
::Slice { ref prefix, ref slice, ref suffix }
,
591 // the test is `$actual_len >= test_len`
592 let pat_len
= (prefix
.len() + suffix
.len()) as u64;
593 match (test_len
.cmp(&pat_len
), slice
) {
594 (Ordering
::Equal
, &Some(_
)) => {
595 // $actual_len >= test_len = pat_len,
597 self.candidate_after_slice_test(
606 (Ordering
::Less
, _
) | (Ordering
::Equal
, &None
) => {
607 // test_len <= pat_len. If $actual_len < test_len,
608 // then it is also < pat_len, so the test passing is
609 // necessary (but insufficient).
612 (Ordering
::Greater
, &None
) => {
613 // test_len > pat_len. If $actual_len >= test_len > pat_len,
614 // then we know we won't have a match.
617 (Ordering
::Greater
, &Some(_
)) => {
618 // test_len < pat_len, and is therefore less
619 // strict. This can still go both ways.
625 (&TestKind
::Range(test
), &PatKind
::Range(pat
)) => {
627 self.candidate_without_match_pair(match_pair_index
, candidate
);
631 let no_overlap
= (|| {
632 use rustc_hir
::RangeEnd
::*;
633 use std
::cmp
::Ordering
::*;
635 let tcx
= self.hir
.tcx();
637 let test_ty
= test
.lo
.ty
;
638 let lo
= compare_const_vals(tcx
, test
.lo
, pat
.hi
, self.hir
.param_env
, test_ty
)?
;
639 let hi
= compare_const_vals(tcx
, test
.hi
, pat
.lo
, self.hir
.param_env
, test_ty
)?
;
641 match (test
.end
, pat
.end
, lo
, hi
) {
644 (_
, Excluded
, Equal
, _
) |
647 (Excluded
, _
, _
, Equal
) => Some(true),
652 if let Some(true) = no_overlap
{
653 // Testing range does not overlap with pattern range,
654 // so the pattern can be matched only if this test fails.
661 (&TestKind
::Range(range
), &PatKind
::Constant { value }
) => {
662 if let Some(false) = self.const_range_contains(range
, value
) {
663 // `value` is not contained in the testing range,
664 // so `value` can be matched only if this test fails.
671 (&TestKind
::Range { .. }
, _
) => None
,
673 (&TestKind
::Eq { .. }
| &TestKind
::Len { .. }
, _
) => {
674 // These are all binary tests.
676 // FIXME(#29623) we can be more clever here
677 let pattern_test
= self.test(&match_pair
);
678 if pattern_test
.kind
== test
.kind
{
679 self.candidate_without_match_pair(match_pair_index
, candidate
);
688 fn candidate_without_match_pair(
690 match_pair_index
: usize,
691 candidate
: &mut Candidate
<'_
, 'tcx
>,
693 candidate
.match_pairs
.remove(match_pair_index
);
696 fn candidate_after_slice_test
<'pat
>(
698 match_pair_index
: usize,
699 candidate
: &mut Candidate
<'pat
, 'tcx
>,
700 prefix
: &'pat
[Pat
<'tcx
>],
701 opt_slice
: Option
<&'pat Pat
<'tcx
>>,
702 suffix
: &'pat
[Pat
<'tcx
>],
704 let removed_place
= candidate
.match_pairs
.remove(match_pair_index
).place
;
705 self.prefix_slice_suffix(
706 &mut candidate
.match_pairs
,
714 fn candidate_after_variant_switch
<'pat
>(
716 match_pair_index
: usize,
717 adt_def
: &'tcx ty
::AdtDef
,
718 variant_index
: VariantIdx
,
719 subpatterns
: &'pat
[FieldPat
<'tcx
>],
720 candidate
: &mut Candidate
<'pat
, 'tcx
>,
722 let match_pair
= candidate
.match_pairs
.remove(match_pair_index
);
723 let tcx
= self.hir
.tcx();
725 // So, if we have a match-pattern like `x @ Enum::Variant(P1, P2)`,
726 // we want to create a set of derived match-patterns like
727 // `(x as Variant).0 @ P1` and `(x as Variant).1 @ P1`.
728 let elem
= ProjectionElem
::Downcast(
729 Some(adt_def
.variants
[variant_index
].ident
.name
),
732 let downcast_place
= tcx
.mk_place_elem(match_pair
.place
, elem
); // `(x as Variant)`
733 let consequent_match_pairs
= subpatterns
.iter().map(|subpattern
| {
734 // e.g., `(x as Variant).0`
735 let place
= tcx
.mk_place_field(downcast_place
, subpattern
.field
, subpattern
.pattern
.ty
);
736 // e.g., `(x as Variant).0 @ P1`
737 MatchPair
::new(place
, &subpattern
.pattern
)
740 candidate
.match_pairs
.extend(consequent_match_pairs
);
743 fn error_simplifyable
<'pat
>(&mut self, match_pair
: &MatchPair
<'pat
, 'tcx
>) -> ! {
744 span_bug
!(match_pair
.pattern
.span
, "simplifyable pattern found: {:?}", match_pair
.pattern
)
747 fn const_range_contains(
749 range
: PatRange
<'tcx
>,
750 value
: &'tcx ty
::Const
<'tcx
>,
752 use std
::cmp
::Ordering
::*;
754 let tcx
= self.hir
.tcx();
756 let a
= compare_const_vals(tcx
, range
.lo
, value
, self.hir
.param_env
, range
.lo
.ty
)?
;
757 let b
= compare_const_vals(tcx
, value
, range
.hi
, self.hir
.param_env
, range
.lo
.ty
)?
;
759 match (b
, range
.end
) {
760 (Less
, _
) | (Equal
, RangeEnd
::Included
) if a
!= Greater
=> Some(true),
765 fn values_not_contained_in_range(
767 range
: PatRange
<'tcx
>,
768 options
: &FxIndexMap
<&'tcx ty
::Const
<'tcx
>, u128
>,
770 for &val
in options
.keys() {
771 if self.const_range_contains(range
, val
)?
{
781 pub(super) fn targets(&self) -> usize {
783 TestKind
::Eq { .. }
| TestKind
::Range(_
) | TestKind
::Len { .. }
=> 2,
784 TestKind
::Switch { adt_def, .. }
=> {
785 // While the switch that we generate doesn't test for all
786 // variants, we have a target for each variant and the
787 // otherwise case, and we make sure that all of the cases not
788 // specified have the same block.
789 adt_def
.variants
.len() + 1
791 TestKind
::SwitchInt { switch_ty, ref options, .. }
=> {
792 if switch_ty
.is_bool() {
793 // `bool` is special cased in `perform_test` to always
794 // branch to two blocks.
804 fn is_switch_ty(ty
: Ty
<'_
>) -> bool
{
805 ty
.is_integral() || ty
.is_char() || ty
.is_bool()