Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs')
| -rw-r--r-- | crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs | 84 |
1 files changed, 43 insertions, 41 deletions
diff --git a/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs b/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs index ca05842879..f45beb4c92 100644 --- a/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs +++ b/crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs @@ -8,7 +8,8 @@ use rustc_hash::FxHashMap; use rustc_pattern_analysis::{ constructor::{Constructor, ConstructorSet, VariantVisibility}, index::IdxContainer, - Captures, PrivateUninhabitedField, TypeCx, + usefulness::{compute_match_usefulness, PlaceValidity, UsefulnessReport}, + Captures, PatCx, PrivateUninhabitedField, }; use smallvec::{smallvec, SmallVec}; use stdx::never; @@ -59,6 +60,18 @@ impl<'p> MatchCheckCtx<'p> { Self { module, body, db, exhaustive_patterns, min_exhaustive_patterns } } + pub(crate) fn compute_match_usefulness( + &self, + arms: &[MatchArm<'p>], + scrut_ty: Ty, + ) -> Result<UsefulnessReport<'p, Self>, ()> { + // FIXME: Determine place validity correctly. For now, err on the safe side. + let place_validity = PlaceValidity::MaybeInvalid; + // Measured to take ~100ms on modern hardware. + let complexity_limit = Some(500000); + compute_match_usefulness(self, arms, scrut_ty, place_validity, complexity_limit) + } + fn is_uninhabited(&self, ty: &Ty) -> bool { is_ty_uninhabited_from(ty, self.module, self.db) } @@ -107,15 +120,17 @@ impl<'p> MatchCheckCtx<'p> { } pub(crate) fn lower_pat(&self, pat: &Pat) -> DeconstructedPat<'p> { - let singleton = |pat| vec![pat]; + let singleton = |pat: DeconstructedPat<'p>| vec![pat.at_index(0)]; let ctor; - let fields: Vec<_>; + let mut fields: Vec<_>; + let arity; match pat.kind.as_ref() { PatKind::Binding { subpattern: Some(subpat), .. } => return self.lower_pat(subpat), PatKind::Binding { subpattern: None, .. } | PatKind::Wild => { ctor = Wildcard; fields = Vec::new(); + arity = 0; } PatKind::Deref { subpattern } => { ctor = match pat.ty.kind(Interner) { @@ -128,23 +143,22 @@ impl<'p> MatchCheckCtx<'p> { } }; fields = singleton(self.lower_pat(subpattern)); + arity = 1; } PatKind::Leaf { subpatterns } | PatKind::Variant { subpatterns, .. } => { + fields = subpatterns + .iter() + .map(|pat| { + let idx: u32 = pat.field.into_raw().into(); + self.lower_pat(&pat.pattern).at_index(idx as usize) + }) + .collect(); match pat.ty.kind(Interner) { TyKind::Tuple(_, substs) => { ctor = Struct; - let mut wilds: Vec<_> = substs - .iter(Interner) - .map(|arg| arg.assert_ty_ref(Interner).clone()) - .map(DeconstructedPat::wildcard) - .collect(); - for pat in subpatterns { - let idx: u32 = pat.field.into_raw().into(); - wilds[idx as usize] = self.lower_pat(&pat.pattern); - } - fields = wilds + arity = substs.len(Interner); } - TyKind::Adt(adt, substs) if is_box(self.db, adt.0) => { + TyKind::Adt(adt, _) if is_box(self.db, adt.0) => { // The only legal patterns of type `Box` (outside `std`) are `_` and box // patterns. If we're here we can assume this is a box pattern. // FIXME(Nadrieril): A `Box` can in theory be matched either with `Box(_, @@ -157,16 +171,9 @@ impl<'p> MatchCheckCtx<'p> { // normally or through box-patterns. We'll have to figure out a proper // solution when we introduce generalized deref patterns. Also need to // prevent mixing of those two options. - let pat = - subpatterns.iter().find(|pat| pat.field.into_raw() == 0u32.into()); - let field = if let Some(pat) = pat { - self.lower_pat(&pat.pattern) - } else { - let ty = substs.at(Interner, 0).assert_ty_ref(Interner).clone(); - DeconstructedPat::wildcard(ty) - }; + fields.retain(|ipat| ipat.idx == 0); ctor = Struct; - fields = singleton(field); + arity = 1; } &TyKind::Adt(adt, _) => { ctor = match pat.kind.as_ref() { @@ -181,37 +188,33 @@ impl<'p> MatchCheckCtx<'p> { } }; let variant = Self::variant_id_for_adt(&ctor, adt.0).unwrap(); - // Fill a vec with wildcards, then place the fields we have at the right - // index. - let mut wilds: Vec<_> = self - .list_variant_fields(&pat.ty, variant) - .map(|(_, ty)| ty) - .map(DeconstructedPat::wildcard) - .collect(); - for pat in subpatterns { - let field_id: u32 = pat.field.into_raw().into(); - wilds[field_id as usize] = self.lower_pat(&pat.pattern); - } - fields = wilds; + arity = variant.variant_data(self.db.upcast()).fields().len(); } _ => { never!("pattern has unexpected type: pat: {:?}, ty: {:?}", pat, &pat.ty); ctor = Wildcard; - fields = Vec::new(); + fields.clear(); + arity = 0; } } } &PatKind::LiteralBool { value } => { ctor = Bool(value); fields = Vec::new(); + arity = 0; } PatKind::Or { pats } => { ctor = Or; - fields = pats.iter().map(|pat| self.lower_pat(pat)).collect(); + fields = pats + .iter() + .enumerate() + .map(|(i, pat)| self.lower_pat(pat).at_index(i)) + .collect(); + arity = pats.len(); } } let data = PatData { db: self.db }; - DeconstructedPat::new(ctor, fields, pat.ty.clone(), data) + DeconstructedPat::new(ctor, fields, arity, pat.ty.clone(), data) } pub(crate) fn hoist_witness_pat(&self, pat: &WitnessPat<'p>) -> Pat { @@ -271,7 +274,7 @@ impl<'p> MatchCheckCtx<'p> { } } -impl<'p> TypeCx for MatchCheckCtx<'p> { +impl<'p> PatCx for MatchCheckCtx<'p> { type Error = (); type Ty = Ty; type VariantIdx = EnumVariantId; @@ -453,7 +456,7 @@ impl<'p> TypeCx for MatchCheckCtx<'p> { let variant = pat.ty().as_adt().and_then(|(adt, _)| Self::variant_id_for_adt(pat.ctor(), adt)); - let db = pat.data().unwrap().db; + let db = pat.data().db; if let Some(variant) = variant { match variant { VariantId::EnumVariantId(v) => { @@ -475,7 +478,6 @@ impl<'p> TypeCx for MatchCheckCtx<'p> { } fn complexity_exceeded(&self) -> Result<(), Self::Error> { - // FIXME(Nadrieril): make use of the complexity counter. Err(()) } } |