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Diffstat (limited to 'compiler/rustc_mir_build/src/build/matches/test.rs')
| -rw-r--r-- | compiler/rustc_mir_build/src/build/matches/test.rs | 837 |
1 files changed, 837 insertions, 0 deletions
diff --git a/compiler/rustc_mir_build/src/build/matches/test.rs b/compiler/rustc_mir_build/src/build/matches/test.rs new file mode 100644 index 000000000..598da80c5 --- /dev/null +++ b/compiler/rustc_mir_build/src/build/matches/test.rs @@ -0,0 +1,837 @@ +// Testing candidates +// +// After candidates have been simplified, the only match pairs that +// remain are those that require some sort of test. The functions here +// identify what tests are needed, perform the tests, and then filter +// the candidates based on the result. + +use crate::build::expr::as_place::PlaceBuilder; +use crate::build::matches::{Candidate, MatchPair, Test, TestKind}; +use crate::build::Builder; +use crate::thir::pattern::compare_const_vals; +use rustc_data_structures::fx::FxIndexMap; +use rustc_hir::{LangItem, RangeEnd}; +use rustc_index::bit_set::BitSet; +use rustc_middle::mir::*; +use rustc_middle::thir::*; +use rustc_middle::ty::subst::{GenericArg, Subst}; +use rustc_middle::ty::util::IntTypeExt; +use rustc_middle::ty::{self, adjustment::PointerCast, Ty, TyCtxt}; +use rustc_span::def_id::DefId; +use rustc_span::symbol::{sym, Symbol}; +use rustc_span::Span; +use rustc_target::abi::VariantIdx; + +use std::cmp::Ordering; + +impl<'a, 'tcx> Builder<'a, 'tcx> { + /// Identifies what test is needed to decide if `match_pair` is applicable. + /// + /// It is a bug to call this with a not-fully-simplified pattern. + pub(super) fn test<'pat>(&mut self, match_pair: &MatchPair<'pat, 'tcx>) -> Test<'tcx> { + match *match_pair.pattern.kind { + PatKind::Variant { adt_def, substs: _, variant_index: _, subpatterns: _ } => Test { + span: match_pair.pattern.span, + kind: TestKind::Switch { + adt_def, + variants: BitSet::new_empty(adt_def.variants().len()), + }, + }, + + PatKind::Constant { .. } if is_switch_ty(match_pair.pattern.ty) => { + // For integers, we use a `SwitchInt` match, which allows + // us to handle more cases. + Test { + span: match_pair.pattern.span, + kind: TestKind::SwitchInt { + switch_ty: match_pair.pattern.ty, + + // these maps are empty to start; cases are + // added below in add_cases_to_switch + options: Default::default(), + }, + } + } + + PatKind::Constant { value } => Test { + span: match_pair.pattern.span, + kind: TestKind::Eq { value, ty: match_pair.pattern.ty }, + }, + + PatKind::Range(range) => { + assert_eq!(range.lo.ty(), match_pair.pattern.ty); + assert_eq!(range.hi.ty(), match_pair.pattern.ty); + Test { span: match_pair.pattern.span, kind: TestKind::Range(range) } + } + + PatKind::Slice { ref prefix, ref slice, ref suffix } => { + let len = prefix.len() + suffix.len(); + let op = if slice.is_some() { BinOp::Ge } else { BinOp::Eq }; + Test { span: match_pair.pattern.span, kind: TestKind::Len { len: len as u64, op } } + } + + PatKind::Or { .. } => bug!("or-patterns should have already been handled"), + + PatKind::AscribeUserType { .. } + | PatKind::Array { .. } + | PatKind::Wild + | PatKind::Binding { .. } + | PatKind::Leaf { .. } + | PatKind::Deref { .. } => self.error_simplifyable(match_pair), + } + } + + pub(super) fn add_cases_to_switch<'pat>( + &mut self, + test_place: &PlaceBuilder<'tcx>, + candidate: &Candidate<'pat, 'tcx>, + switch_ty: Ty<'tcx>, + options: &mut FxIndexMap<ConstantKind<'tcx>, u128>, + ) -> bool { + let Some(match_pair) = candidate.match_pairs.iter().find(|mp| mp.place == *test_place) else { + return false; + }; + + match *match_pair.pattern.kind { + PatKind::Constant { value } => { + options + .entry(value) + .or_insert_with(|| value.eval_bits(self.tcx, self.param_env, switch_ty)); + true + } + PatKind::Variant { .. } => { + panic!("you should have called add_variants_to_switch instead!"); + } + PatKind::Range(range) => { + // Check that none of the switch values are in the range. + self.values_not_contained_in_range(range, options).unwrap_or(false) + } + PatKind::Slice { .. } + | PatKind::Array { .. } + | PatKind::Wild + | PatKind::Or { .. } + | PatKind::Binding { .. } + | PatKind::AscribeUserType { .. } + | PatKind::Leaf { .. } + | PatKind::Deref { .. } => { + // don't know how to add these patterns to a switch + false + } + } + } + + pub(super) fn add_variants_to_switch<'pat>( + &mut self, + test_place: &PlaceBuilder<'tcx>, + candidate: &Candidate<'pat, 'tcx>, + variants: &mut BitSet<VariantIdx>, + ) -> bool { + let Some(match_pair) = candidate.match_pairs.iter().find(|mp| mp.place == *test_place) else { + return false; + }; + + match *match_pair.pattern.kind { + PatKind::Variant { adt_def: _, variant_index, .. } => { + // We have a pattern testing for variant `variant_index` + // set the corresponding index to true + variants.insert(variant_index); + true + } + _ => { + // don't know how to add these patterns to a switch + false + } + } + } + + pub(super) fn perform_test( + &mut self, + match_start_span: Span, + scrutinee_span: Span, + block: BasicBlock, + place_builder: PlaceBuilder<'tcx>, + test: &Test<'tcx>, + make_target_blocks: impl FnOnce(&mut Self) -> Vec<BasicBlock>, + ) { + let place: Place<'tcx>; + if let Ok(test_place_builder) = + place_builder.try_upvars_resolved(self.tcx, self.typeck_results) + { + place = test_place_builder.into_place(self.tcx, self.typeck_results); + } else { + return; + } + debug!( + "perform_test({:?}, {:?}: {:?}, {:?})", + block, + place, + place.ty(&self.local_decls, self.tcx), + test + ); + + let source_info = self.source_info(test.span); + match test.kind { + TestKind::Switch { adt_def, ref variants } => { + let target_blocks = make_target_blocks(self); + // Variants is a BitVec of indexes into adt_def.variants. + let num_enum_variants = adt_def.variants().len(); + debug_assert_eq!(target_blocks.len(), num_enum_variants + 1); + let otherwise_block = *target_blocks.last().unwrap(); + let tcx = self.tcx; + let switch_targets = SwitchTargets::new( + adt_def.discriminants(tcx).filter_map(|(idx, discr)| { + if variants.contains(idx) { + debug_assert_ne!( + target_blocks[idx.index()], + otherwise_block, + "no canididates for tested discriminant: {:?}", + discr, + ); + Some((discr.val, target_blocks[idx.index()])) + } else { + debug_assert_eq!( + target_blocks[idx.index()], + otherwise_block, + "found canididates for untested discriminant: {:?}", + discr, + ); + None + } + }), + otherwise_block, + ); + debug!("num_enum_variants: {}, variants: {:?}", num_enum_variants, variants); + let discr_ty = adt_def.repr().discr_type().to_ty(tcx); + let discr = self.temp(discr_ty, test.span); + self.cfg.push_assign( + block, + self.source_info(scrutinee_span), + discr, + Rvalue::Discriminant(place), + ); + self.cfg.terminate( + block, + self.source_info(match_start_span), + TerminatorKind::SwitchInt { + discr: Operand::Move(discr), + switch_ty: discr_ty, + targets: switch_targets, + }, + ); + } + + TestKind::SwitchInt { switch_ty, ref options } => { + let target_blocks = make_target_blocks(self); + let terminator = if *switch_ty.kind() == ty::Bool { + assert!(!options.is_empty() && options.len() <= 2); + let [first_bb, second_bb] = *target_blocks else { + bug!("`TestKind::SwitchInt` on `bool` should have two targets") + }; + let (true_bb, false_bb) = match options[0] { + 1 => (first_bb, second_bb), + 0 => (second_bb, first_bb), + v => span_bug!(test.span, "expected boolean value but got {:?}", v), + }; + TerminatorKind::if_(self.tcx, Operand::Copy(place), true_bb, false_bb) + } else { + // The switch may be inexhaustive so we have a catch all block + debug_assert_eq!(options.len() + 1, target_blocks.len()); + let otherwise_block = *target_blocks.last().unwrap(); + let switch_targets = SwitchTargets::new( + options.values().copied().zip(target_blocks), + otherwise_block, + ); + TerminatorKind::SwitchInt { + discr: Operand::Copy(place), + switch_ty, + targets: switch_targets, + } + }; + self.cfg.terminate(block, self.source_info(match_start_span), terminator); + } + + TestKind::Eq { value, ty } => { + if !ty.is_scalar() { + // Use `PartialEq::eq` instead of `BinOp::Eq` + // (the binop can only handle primitives) + self.non_scalar_compare( + block, + make_target_blocks, + source_info, + value, + place, + ty, + ); + } else if let [success, fail] = *make_target_blocks(self) { + assert_eq!(value.ty(), ty); + let expect = self.literal_operand(test.span, value); + let val = Operand::Copy(place); + self.compare(block, success, fail, source_info, BinOp::Eq, expect, val); + } else { + bug!("`TestKind::Eq` should have two target blocks"); + } + } + + TestKind::Range(PatRange { lo, hi, ref end }) => { + let lower_bound_success = self.cfg.start_new_block(); + let target_blocks = make_target_blocks(self); + + // Test `val` by computing `lo <= val && val <= hi`, using primitive comparisons. + let lo = self.literal_operand(test.span, lo); + let hi = self.literal_operand(test.span, hi); + let val = Operand::Copy(place); + + let [success, fail] = *target_blocks else { + bug!("`TestKind::Range` should have two target blocks"); + }; + self.compare( + block, + lower_bound_success, + fail, + source_info, + BinOp::Le, + lo, + val.clone(), + ); + let op = match *end { + RangeEnd::Included => BinOp::Le, + RangeEnd::Excluded => BinOp::Lt, + }; + self.compare(lower_bound_success, success, fail, source_info, op, val, hi); + } + + TestKind::Len { len, op } => { + let target_blocks = make_target_blocks(self); + + let usize_ty = self.tcx.types.usize; + let actual = self.temp(usize_ty, test.span); + + // actual = len(place) + self.cfg.push_assign(block, source_info, actual, Rvalue::Len(place)); + + // expected = <N> + let expected = self.push_usize(block, source_info, len); + + let [true_bb, false_bb] = *target_blocks else { + bug!("`TestKind::Len` should have two target blocks"); + }; + // result = actual == expected OR result = actual < expected + // branch based on result + self.compare( + block, + true_bb, + false_bb, + source_info, + op, + Operand::Move(actual), + Operand::Move(expected), + ); + } + } + } + + /// Compare using the provided built-in comparison operator + fn compare( + &mut self, + block: BasicBlock, + success_block: BasicBlock, + fail_block: BasicBlock, + source_info: SourceInfo, + op: BinOp, + left: Operand<'tcx>, + right: Operand<'tcx>, + ) { + let bool_ty = self.tcx.types.bool; + let result = self.temp(bool_ty, source_info.span); + + // result = op(left, right) + self.cfg.push_assign( + block, + source_info, + result, + Rvalue::BinaryOp(op, Box::new((left, right))), + ); + + // branch based on result + self.cfg.terminate( + block, + source_info, + TerminatorKind::if_(self.tcx, Operand::Move(result), success_block, fail_block), + ); + } + + /// Compare two `&T` values using `<T as std::compare::PartialEq>::eq` + fn non_scalar_compare( + &mut self, + block: BasicBlock, + make_target_blocks: impl FnOnce(&mut Self) -> Vec<BasicBlock>, + source_info: SourceInfo, + value: ConstantKind<'tcx>, + place: Place<'tcx>, + mut ty: Ty<'tcx>, + ) { + let mut expect = self.literal_operand(source_info.span, value); + let mut val = Operand::Copy(place); + + // If we're using `b"..."` as a pattern, we need to insert an + // unsizing coercion, as the byte string has the type `&[u8; N]`. + // + // We want to do this even when the scrutinee is a reference to an + // array, so we can call `<[u8]>::eq` rather than having to find an + // `<[u8; N]>::eq`. + let unsize = |ty: Ty<'tcx>| match ty.kind() { + ty::Ref(region, rty, _) => match rty.kind() { + ty::Array(inner_ty, n) => Some((region, inner_ty, n)), + _ => None, + }, + _ => None, + }; + let opt_ref_ty = unsize(ty); + let opt_ref_test_ty = unsize(value.ty()); + match (opt_ref_ty, opt_ref_test_ty) { + // nothing to do, neither is an array + (None, None) => {} + (Some((region, elem_ty, _)), _) | (None, Some((region, elem_ty, _))) => { + let tcx = self.tcx; + // make both a slice + ty = tcx.mk_imm_ref(*region, tcx.mk_slice(*elem_ty)); + if opt_ref_ty.is_some() { + let temp = self.temp(ty, source_info.span); + self.cfg.push_assign( + block, + source_info, + temp, + Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), val, ty), + ); + val = Operand::Move(temp); + } + if opt_ref_test_ty.is_some() { + let slice = self.temp(ty, source_info.span); + self.cfg.push_assign( + block, + source_info, + slice, + Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), expect, ty), + ); + expect = Operand::Move(slice); + } + } + } + + let ty::Ref(_, deref_ty, _) = *ty.kind() else { + bug!("non_scalar_compare called on non-reference type: {}", ty); + }; + + let eq_def_id = self.tcx.require_lang_item(LangItem::PartialEq, None); + let method = trait_method(self.tcx, eq_def_id, sym::eq, deref_ty, &[deref_ty.into()]); + + let bool_ty = self.tcx.types.bool; + let eq_result = self.temp(bool_ty, source_info.span); + let eq_block = self.cfg.start_new_block(); + self.cfg.terminate( + block, + source_info, + TerminatorKind::Call { + func: Operand::Constant(Box::new(Constant { + span: source_info.span, + + // FIXME(#54571): This constant comes from user input (a + // constant in a pattern). Are there forms where users can add + // type annotations here? For example, an associated constant? + // Need to experiment. + user_ty: None, + + literal: method, + })), + args: vec![val, expect], + destination: eq_result, + target: Some(eq_block), + cleanup: None, + from_hir_call: false, + fn_span: source_info.span, + }, + ); + self.diverge_from(block); + + let [success_block, fail_block] = *make_target_blocks(self) else { + bug!("`TestKind::Eq` should have two target blocks") + }; + // check the result + self.cfg.terminate( + eq_block, + source_info, + TerminatorKind::if_(self.tcx, Operand::Move(eq_result), success_block, fail_block), + ); + } + + /// Given that we are performing `test` against `test_place`, this job + /// sorts out what the status of `candidate` will be after the test. See + /// `test_candidates` for the usage of this function. The returned index is + /// the index that this candidate should be placed in the + /// `target_candidates` vec. The candidate may be modified to update its + /// `match_pairs`. + /// + /// So, for example, if this candidate is `x @ Some(P0)` and the `Test` is + /// a variant test, then we would modify the candidate to be `(x as + /// Option).0 @ P0` and return the index corresponding to the variant + /// `Some`. + /// + /// However, in some cases, the test may just not be relevant to candidate. + /// For example, suppose we are testing whether `foo.x == 22`, but in one + /// match arm we have `Foo { x: _, ... }`... in that case, the test for + /// what value `x` has has no particular relevance to this candidate. In + /// such cases, this function just returns None without doing anything. + /// This is used by the overall `match_candidates` algorithm to structure + /// the match as a whole. See `match_candidates` for more details. + /// + /// FIXME(#29623). In some cases, we have some tricky choices to make. for + /// example, if we are testing that `x == 22`, but the candidate is `x @ + /// 13..55`, what should we do? In the event that the test is true, we know + /// that the candidate applies, but in the event of false, we don't know + /// that it *doesn't* apply. For now, we return false, indicate that the + /// test does not apply to this candidate, but it might be we can get + /// tighter match code if we do something a bit different. + pub(super) fn sort_candidate<'pat>( + &mut self, + test_place: &PlaceBuilder<'tcx>, + test: &Test<'tcx>, + candidate: &mut Candidate<'pat, 'tcx>, + ) -> Option<usize> { + // Find the match_pair for this place (if any). At present, + // afaik, there can be at most one. (In the future, if we + // adopted a more general `@` operator, there might be more + // than one, but it'd be very unusual to have two sides that + // both require tests; you'd expect one side to be simplified + // away.) + let (match_pair_index, match_pair) = + candidate.match_pairs.iter().enumerate().find(|&(_, mp)| mp.place == *test_place)?; + + match (&test.kind, &*match_pair.pattern.kind) { + // If we are performing a variant switch, then this + // informs variant patterns, but nothing else. + ( + &TestKind::Switch { adt_def: tested_adt_def, .. }, + &PatKind::Variant { adt_def, variant_index, ref subpatterns, .. }, + ) => { + assert_eq!(adt_def, tested_adt_def); + self.candidate_after_variant_switch( + match_pair_index, + adt_def, + variant_index, + subpatterns, + candidate, + ); + Some(variant_index.as_usize()) + } + + (&TestKind::Switch { .. }, _) => None, + + // If we are performing a switch over integers, then this informs integer + // equality, but nothing else. + // + // FIXME(#29623) we could use PatKind::Range to rule + // things out here, in some cases. + ( + &TestKind::SwitchInt { switch_ty: _, ref options }, + &PatKind::Constant { ref value }, + ) if is_switch_ty(match_pair.pattern.ty) => { + let index = options.get_index_of(value).unwrap(); + self.candidate_without_match_pair(match_pair_index, candidate); + Some(index) + } + + (&TestKind::SwitchInt { switch_ty: _, ref options }, &PatKind::Range(range)) => { + let not_contained = + self.values_not_contained_in_range(range, options).unwrap_or(false); + + if not_contained { + // No switch values are contained in the pattern range, + // so the pattern can be matched only if this test fails. + let otherwise = options.len(); + Some(otherwise) + } else { + None + } + } + + (&TestKind::SwitchInt { .. }, _) => None, + + ( + &TestKind::Len { len: test_len, op: BinOp::Eq }, + &PatKind::Slice { ref prefix, ref slice, ref suffix }, + ) => { + let pat_len = (prefix.len() + suffix.len()) as u64; + match (test_len.cmp(&pat_len), slice) { + (Ordering::Equal, &None) => { + // on true, min_len = len = $actual_length, + // on false, len != $actual_length + self.candidate_after_slice_test( + match_pair_index, + candidate, + prefix, + slice.as_ref(), + suffix, + ); + Some(0) + } + (Ordering::Less, _) => { + // test_len < pat_len. If $actual_len = test_len, + // then $actual_len < pat_len and we don't have + // enough elements. + Some(1) + } + (Ordering::Equal | Ordering::Greater, &Some(_)) => { + // This can match both if $actual_len = test_len >= pat_len, + // and if $actual_len > test_len. We can't advance. + None + } + (Ordering::Greater, &None) => { + // test_len != pat_len, so if $actual_len = test_len, then + // $actual_len != pat_len. + Some(1) + } + } + } + + ( + &TestKind::Len { len: test_len, op: BinOp::Ge }, + &PatKind::Slice { ref prefix, ref slice, ref suffix }, + ) => { + // the test is `$actual_len >= test_len` + let pat_len = (prefix.len() + suffix.len()) as u64; + match (test_len.cmp(&pat_len), slice) { + (Ordering::Equal, &Some(_)) => { + // $actual_len >= test_len = pat_len, + // so we can match. + self.candidate_after_slice_test( + match_pair_index, + candidate, + prefix, + slice.as_ref(), + suffix, + ); + Some(0) + } + (Ordering::Less, _) | (Ordering::Equal, &None) => { + // test_len <= pat_len. If $actual_len < test_len, + // then it is also < pat_len, so the test passing is + // necessary (but insufficient). + Some(0) + } + (Ordering::Greater, &None) => { + // test_len > pat_len. If $actual_len >= test_len > pat_len, + // then we know we won't have a match. + Some(1) + } + (Ordering::Greater, &Some(_)) => { + // test_len < pat_len, and is therefore less + // strict. This can still go both ways. + None + } + } + } + + (&TestKind::Range(test), &PatKind::Range(pat)) => { + use std::cmp::Ordering::*; + + if test == pat { + self.candidate_without_match_pair(match_pair_index, candidate); + return Some(0); + } + + // For performance, it's important to only do the second + // `compare_const_vals` if necessary. + let no_overlap = if matches!( + (compare_const_vals(self.tcx, test.hi, pat.lo, self.param_env)?, test.end), + (Less, _) | (Equal, RangeEnd::Excluded) // test < pat + ) || matches!( + (compare_const_vals(self.tcx, test.lo, pat.hi, self.param_env)?, pat.end), + (Greater, _) | (Equal, RangeEnd::Excluded) // test > pat + ) { + Some(1) + } else { + None + }; + + // If the testing range does not overlap with pattern range, + // the pattern can be matched only if this test fails. + no_overlap + } + + (&TestKind::Range(range), &PatKind::Constant { value }) => { + if let Some(false) = self.const_range_contains(range, value) { + // `value` is not contained in the testing range, + // so `value` can be matched only if this test fails. + Some(1) + } else { + None + } + } + + (&TestKind::Range { .. }, _) => None, + + (&TestKind::Eq { .. } | &TestKind::Len { .. }, _) => { + // The call to `self.test(&match_pair)` below is not actually used to generate any + // MIR. Instead, we just want to compare with `test` (the parameter of the method) + // to see if it is the same. + // + // However, at this point we can still encounter or-patterns that were extracted + // from previous calls to `sort_candidate`, so we need to manually address that + // case to avoid panicking in `self.test()`. + if let PatKind::Or { .. } = &*match_pair.pattern.kind { + return None; + } + + // These are all binary tests. + // + // FIXME(#29623) we can be more clever here + let pattern_test = self.test(&match_pair); + if pattern_test.kind == test.kind { + self.candidate_without_match_pair(match_pair_index, candidate); + Some(0) + } else { + None + } + } + } + } + + fn candidate_without_match_pair( + &mut self, + match_pair_index: usize, + candidate: &mut Candidate<'_, 'tcx>, + ) { + candidate.match_pairs.remove(match_pair_index); + } + + fn candidate_after_slice_test<'pat>( + &mut self, + match_pair_index: usize, + candidate: &mut Candidate<'pat, 'tcx>, + prefix: &'pat [Pat<'tcx>], + opt_slice: Option<&'pat Pat<'tcx>>, + suffix: &'pat [Pat<'tcx>], + ) { + let removed_place = candidate.match_pairs.remove(match_pair_index).place; + self.prefix_slice_suffix( + &mut candidate.match_pairs, + &removed_place, + prefix, + opt_slice, + suffix, + ); + } + + fn candidate_after_variant_switch<'pat>( + &mut self, + match_pair_index: usize, + adt_def: ty::AdtDef<'tcx>, + variant_index: VariantIdx, + subpatterns: &'pat [FieldPat<'tcx>], + candidate: &mut Candidate<'pat, 'tcx>, + ) { + let match_pair = candidate.match_pairs.remove(match_pair_index); + + // So, if we have a match-pattern like `x @ Enum::Variant(P1, P2)`, + // we want to create a set of derived match-patterns like + // `(x as Variant).0 @ P1` and `(x as Variant).1 @ P1`. + let elem = + ProjectionElem::Downcast(Some(adt_def.variant(variant_index).name), variant_index); + let downcast_place = match_pair.place.project(elem); // `(x as Variant)` + let consequent_match_pairs = subpatterns.iter().map(|subpattern| { + // e.g., `(x as Variant).0` + let place = downcast_place.clone().field(subpattern.field, subpattern.pattern.ty); + // e.g., `(x as Variant).0 @ P1` + MatchPair::new(place, &subpattern.pattern) + }); + + candidate.match_pairs.extend(consequent_match_pairs); + } + + fn error_simplifyable<'pat>(&mut self, match_pair: &MatchPair<'pat, 'tcx>) -> ! { + span_bug!(match_pair.pattern.span, "simplifyable pattern found: {:?}", match_pair.pattern) + } + + fn const_range_contains( + &self, + range: PatRange<'tcx>, + value: ConstantKind<'tcx>, + ) -> Option<bool> { + use std::cmp::Ordering::*; + + // For performance, it's important to only do the second + // `compare_const_vals` if necessary. + Some( + matches!(compare_const_vals(self.tcx, range.lo, value, self.param_env)?, Less | Equal) + && matches!( + (compare_const_vals(self.tcx, value, range.hi, self.param_env)?, range.end), + (Less, _) | (Equal, RangeEnd::Included) + ), + ) + } + + fn values_not_contained_in_range( + &self, + range: PatRange<'tcx>, + options: &FxIndexMap<ConstantKind<'tcx>, u128>, + ) -> Option<bool> { + for &val in options.keys() { + if self.const_range_contains(range, val)? { + return Some(false); + } + } + + Some(true) + } +} + +impl Test<'_> { + pub(super) fn targets(&self) -> usize { + match self.kind { + TestKind::Eq { .. } | TestKind::Range(_) | TestKind::Len { .. } => 2, + TestKind::Switch { adt_def, .. } => { + // While the switch that we generate doesn't test for all + // variants, we have a target for each variant and the + // otherwise case, and we make sure that all of the cases not + // specified have the same block. + adt_def.variants().len() + 1 + } + TestKind::SwitchInt { switch_ty, ref options, .. } => { + if switch_ty.is_bool() { + // `bool` is special cased in `perform_test` to always + // branch to two blocks. + 2 + } else { + options.len() + 1 + } + } + } + } +} + +fn is_switch_ty(ty: Ty<'_>) -> bool { + ty.is_integral() || ty.is_char() || ty.is_bool() +} + +fn trait_method<'tcx>( + tcx: TyCtxt<'tcx>, + trait_def_id: DefId, + method_name: Symbol, + self_ty: Ty<'tcx>, + params: &[GenericArg<'tcx>], +) -> ConstantKind<'tcx> { + let substs = tcx.mk_substs_trait(self_ty, params); + + // The unhygienic comparison here is acceptable because this is only + // used on known traits. + let item = tcx + .associated_items(trait_def_id) + .filter_by_name_unhygienic(method_name) + .find(|item| item.kind == ty::AssocKind::Fn) + .expect("trait method not found"); + + let method_ty = tcx.bound_type_of(item.def_id); + let method_ty = method_ty.subst(tcx, substs); + + ConstantKind::zero_sized(method_ty) +} |