diff options
Diffstat (limited to 'compiler/rustc_pattern_analysis/src/rustc.rs')
| -rw-r--r-- | compiler/rustc_pattern_analysis/src/rustc.rs | 79 |
1 files changed, 35 insertions, 44 deletions
diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs index ec37e202118..a8fe0cb6a1d 100644 --- a/compiler/rustc_pattern_analysis/src/rustc.rs +++ b/compiler/rustc_pattern_analysis/src/rustc.rs @@ -1,8 +1,7 @@ -use smallvec::SmallVec; use std::fmt; use std::iter::once; -use rustc_arena::{DroplessArena, TypedArena}; +use rustc_arena::DroplessArena; use rustc_hir::def_id::DefId; use rustc_hir::HirId; use rustc_index::{Idx, IndexVec}; @@ -27,8 +26,7 @@ use crate::constructor::Constructor::*; pub type Constructor<'p, 'tcx> = crate::constructor::Constructor<RustcMatchCheckCtxt<'p, 'tcx>>; pub type ConstructorSet<'p, 'tcx> = crate::constructor::ConstructorSet<RustcMatchCheckCtxt<'p, 'tcx>>; -pub type DeconstructedPat<'p, 'tcx> = - crate::pat::DeconstructedPat<'p, RustcMatchCheckCtxt<'p, 'tcx>>; +pub type DeconstructedPat<'p, 'tcx> = crate::pat::DeconstructedPat<RustcMatchCheckCtxt<'p, 'tcx>>; pub type MatchArm<'p, 'tcx> = crate::MatchArm<'p, RustcMatchCheckCtxt<'p, 'tcx>>; pub type Usefulness<'p, 'tcx> = crate::usefulness::Usefulness<'p, RustcMatchCheckCtxt<'p, 'tcx>>; pub type UsefulnessReport<'p, 'tcx> = @@ -64,7 +62,7 @@ impl<'tcx> RevealedTy<'tcx> { } #[derive(Clone)] -pub struct RustcMatchCheckCtxt<'p, 'tcx> { +pub struct RustcMatchCheckCtxt<'p, 'tcx: 'p> { pub tcx: TyCtxt<'tcx>, pub typeck_results: &'tcx ty::TypeckResults<'tcx>, /// The module in which the match occurs. This is necessary for @@ -74,8 +72,6 @@ pub struct RustcMatchCheckCtxt<'p, 'tcx> { /// outside its module and should not be matchable with an empty match statement. pub module: DefId, pub param_env: ty::ParamEnv<'tcx>, - /// To allocate lowered patterns - pub pattern_arena: &'p TypedArena<DeconstructedPat<'p, 'tcx>>, /// To allocate the result of `self.ctor_sub_tys()` pub dropless_arena: &'p DroplessArena, /// Lint level at the match. @@ -91,13 +87,13 @@ pub struct RustcMatchCheckCtxt<'p, 'tcx> { pub known_valid_scrutinee: bool, } -impl<'p, 'tcx> fmt::Debug for RustcMatchCheckCtxt<'p, 'tcx> { +impl<'p, 'tcx: 'p> fmt::Debug for RustcMatchCheckCtxt<'p, 'tcx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_struct("RustcMatchCheckCtxt").finish() } } -impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { +impl<'p, 'tcx: 'p> RustcMatchCheckCtxt<'p, 'tcx> { /// Type inference occasionally gives us opaque types in places where corresponding patterns /// have more specific types. To avoid inconsistencies as well as detect opaque uninhabited /// types, we use the corresponding concrete type if possible. @@ -423,7 +419,8 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { | ty::FnDef(_, _) | ty::FnPtr(_) | ty::Dynamic(_, _, _) - | ty::Closure(_, _) + | ty::Closure(..) + | ty::CoroutineClosure(..) | ty::Coroutine(_, _) | ty::Alias(_, _) | ty::Param(_) @@ -458,21 +455,20 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { /// Note: the input patterns must have been lowered through /// `rustc_mir_build::thir::pattern::check_match::MatchVisitor::lower_pattern`. pub fn lower_pat(&self, pat: &'p Pat<'tcx>) -> DeconstructedPat<'p, 'tcx> { - let singleton = |pat| std::slice::from_ref(self.pattern_arena.alloc(pat)); let cx = self; let ty = cx.reveal_opaque_ty(pat.ty); let ctor; - let fields: &[_]; + let mut fields: Vec<_>; match &pat.kind { PatKind::AscribeUserType { subpattern, .. } | PatKind::InlineConstant { subpattern, .. } => return self.lower_pat(subpattern), PatKind::Binding { subpattern: Some(subpat), .. } => return self.lower_pat(subpat), PatKind::Binding { subpattern: None, .. } | PatKind::Wild => { ctor = Wildcard; - fields = &[]; + fields = vec![]; } PatKind::Deref { subpattern } => { - fields = singleton(self.lower_pat(subpattern)); + fields = vec![self.lower_pat(subpattern)]; ctor = match ty.kind() { // This is a box pattern. ty::Adt(adt, ..) if adt.is_box() => Struct, @@ -484,15 +480,14 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { match ty.kind() { ty::Tuple(fs) => { ctor = Struct; - let mut wilds: SmallVec<[_; 2]> = fs + fields = fs .iter() .map(|ty| cx.reveal_opaque_ty(ty)) .map(|ty| DeconstructedPat::wildcard(ty)) .collect(); for pat in subpatterns { - wilds[pat.field.index()] = self.lower_pat(&pat.pattern); + fields[pat.field.index()] = self.lower_pat(&pat.pattern); } - fields = cx.pattern_arena.alloc_from_iter(wilds); } ty::Adt(adt, args) if adt.is_box() => { // The only legal patterns of type `Box` (outside `std`) are `_` and box @@ -514,7 +509,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { DeconstructedPat::wildcard(self.reveal_opaque_ty(args.type_at(0))) }; ctor = Struct; - fields = singleton(pat); + fields = vec![pat]; } ty::Adt(adt, _) => { ctor = match pat.kind { @@ -534,14 +529,12 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { ty }, ); - let mut wilds: SmallVec<[_; 2]> = - tys.map(|ty| DeconstructedPat::wildcard(ty)).collect(); + fields = tys.map(|ty| DeconstructedPat::wildcard(ty)).collect(); for pat in subpatterns { if let Some(i) = field_id_to_id[pat.field.index()] { - wilds[i] = self.lower_pat(&pat.pattern); + fields[i] = self.lower_pat(&pat.pattern); } } - fields = cx.pattern_arena.alloc_from_iter(wilds); } _ => bug!("pattern has unexpected type: pat: {:?}, ty: {:?}", pat, ty), } @@ -553,7 +546,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { Some(b) => Bool(b), None => Opaque(OpaqueId::new()), }; - fields = &[]; + fields = vec![]; } ty::Char | ty::Int(_) | ty::Uint(_) => { ctor = match value.try_eval_bits(cx.tcx, cx.param_env) { @@ -569,7 +562,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { } None => Opaque(OpaqueId::new()), }; - fields = &[]; + fields = vec![]; } ty::Float(ty::FloatTy::F32) => { ctor = match value.try_eval_bits(cx.tcx, cx.param_env) { @@ -580,7 +573,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { } None => Opaque(OpaqueId::new()), }; - fields = &[]; + fields = vec![]; } ty::Float(ty::FloatTy::F64) => { ctor = match value.try_eval_bits(cx.tcx, cx.param_env) { @@ -591,7 +584,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { } None => Opaque(OpaqueId::new()), }; - fields = &[]; + fields = vec![]; } ty::Ref(_, t, _) if t.is_str() => { // We want a `&str` constant to behave like a `Deref` pattern, to be compatible @@ -602,16 +595,16 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { // subfields. // Note: `t` is `str`, not `&str`. let ty = self.reveal_opaque_ty(*t); - let subpattern = DeconstructedPat::new(Str(*value), &[], ty, pat); + let subpattern = DeconstructedPat::new(Str(*value), Vec::new(), ty, pat); ctor = Ref; - fields = singleton(subpattern) + fields = vec![subpattern] } // All constants that can be structurally matched have already been expanded // into the corresponding `Pat`s by `const_to_pat`. Constants that remain are // opaque. _ => { ctor = Opaque(OpaqueId::new()); - fields = &[]; + fields = vec![]; } } } @@ -648,7 +641,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { } _ => bug!("invalid type for range pattern: {}", ty.inner()), }; - fields = &[]; + fields = vec![]; } PatKind::Array { prefix, slice, suffix } | PatKind::Slice { prefix, slice, suffix } => { let array_len = match ty.kind() { @@ -664,25 +657,23 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { SliceKind::FixedLen(prefix.len() + suffix.len()) }; ctor = Slice(Slice::new(array_len, kind)); - fields = cx.pattern_arena.alloc_from_iter( - prefix.iter().chain(suffix.iter()).map(|p| self.lower_pat(&*p)), - ) + fields = prefix.iter().chain(suffix.iter()).map(|p| self.lower_pat(&*p)).collect(); } PatKind::Or { .. } => { ctor = Or; let pats = expand_or_pat(pat); - fields = - cx.pattern_arena.alloc_from_iter(pats.into_iter().map(|p| self.lower_pat(p))) + fields = pats.into_iter().map(|p| self.lower_pat(p)).collect(); } PatKind::Never => { - // FIXME(never_patterns): handle `!` in exhaustiveness. This is a sane default - // in the meantime. + // A never pattern matches all the values of its type (namely none). Moreover it + // must be compatible with other constructors, since we can use `!` on a type like + // `Result<!, !>` which has other constructors. Hence we lower it as a wildcard. ctor = Wildcard; - fields = &[]; + fields = vec![]; } PatKind::Error(_) => { ctor = Opaque(OpaqueId::new()); - fields = &[]; + fields = vec![]; } } DeconstructedPat::new(ctor, fields, ty, pat) @@ -853,7 +844,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { } } -impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> { +impl<'p, 'tcx: 'p> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> { type Ty = RevealedTy<'tcx>; type Error = ErrorGuaranteed; type VariantIdx = VariantIdx; @@ -887,7 +878,7 @@ impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> { fn write_variant_name( f: &mut fmt::Formatter<'_>, - pat: &crate::pat::DeconstructedPat<'_, Self>, + pat: &crate::pat::DeconstructedPat<Self>, ) -> fmt::Result { if let ty::Adt(adt, _) = pat.ty().kind() { if adt.is_box() { @@ -900,15 +891,15 @@ impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> { Ok(()) } - fn bug(&self, fmt: fmt::Arguments<'_>) -> ! { + fn bug(&self, fmt: fmt::Arguments<'_>) -> Self::Error { span_bug!(self.scrut_span, "{}", fmt) } fn lint_overlapping_range_endpoints( &self, - pat: &crate::pat::DeconstructedPat<'_, Self>, + pat: &crate::pat::DeconstructedPat<Self>, overlaps_on: IntRange, - overlaps_with: &[&crate::pat::DeconstructedPat<'_, Self>], + overlaps_with: &[&crate::pat::DeconstructedPat<Self>], ) { let overlap_as_pat = self.hoist_pat_range(&overlaps_on, *pat.ty()); let overlaps: Vec<_> = overlaps_with |