From 3dfd0fd85840bd60fb2956297d6073d791b81d4d Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Sun, 17 Mar 2024 15:48:27 +0100 Subject: Report arm intersections --- compiler/rustc_pattern_analysis/src/usefulness.rs | 25 +++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) (limited to 'compiler/rustc_pattern_analysis/src') diff --git a/compiler/rustc_pattern_analysis/src/usefulness.rs b/compiler/rustc_pattern_analysis/src/usefulness.rs index 3760db8b688..cdc03eaeb37 100644 --- a/compiler/rustc_pattern_analysis/src/usefulness.rs +++ b/compiler/rustc_pattern_analysis/src/usefulness.rs @@ -1042,7 +1042,7 @@ struct MatrixRow<'p, Cx: PatCx> { is_under_guard: bool, /// When we specialize, we remember which row of the original matrix produced a given row of the /// specialized matrix. When we unspecialize, we use this to propagate usefulness back up the - /// callstack. + /// callstack. On creation, this stores the index of the original match arm. parent_row: usize, /// False when the matrix is just built. This is set to `true` by /// [`compute_exhaustiveness_and_usefulness`] if the arm is found to be useful. @@ -1163,10 +1163,10 @@ impl<'p, Cx: PatCx> Matrix<'p, Cx> { place_info: smallvec![place_info], wildcard_row_is_relevant: true, }; - for (row_id, arm) in arms.iter().enumerate() { + for (arm_id, arm) in arms.iter().enumerate() { let v = MatrixRow { pats: PatStack::from_pattern(arm.pat), - parent_row: row_id, // dummy, we don't read it + parent_row: arm_id, is_under_guard: arm.has_guard, useful: false, intersects: BitSet::new_empty(0), // Initialized in `Matrix::expand_and_push`. @@ -1738,6 +1738,9 @@ pub struct UsefulnessReport<'p, Cx: PatCx> { /// If the match is exhaustive, this is empty. If not, this contains witnesses for the lack of /// exhaustiveness. pub non_exhaustiveness_witnesses: Vec>, + /// For each arm, a set of indices of arms above it that have non-empty intersection, i.e. there + /// is a value matched by both arms. This may miss real intersections. + pub arm_intersections: Vec>, } /// Computes whether a match is exhaustive and which of its arms are useful. @@ -1769,5 +1772,19 @@ pub fn compute_match_usefulness<'p, Cx: PatCx>( }) .collect(); - Ok(UsefulnessReport { arm_usefulness, non_exhaustiveness_witnesses }) + let mut arm_intersections: Vec<_> = + arms.iter().enumerate().map(|(i, _)| BitSet::new_empty(i)).collect(); + for row in matrix.rows() { + let arm_id = row.parent_row; + for intersection in row.intersects.iter() { + // Convert the matrix row ids into arm ids (they can differ because we expand or-patterns). + let arm_intersection = matrix.rows[intersection].parent_row; + // Note: self-intersection can happen with or-patterns. + if arm_intersection != arm_id { + arm_intersections[arm_id].insert(arm_intersection); + } + } + } + + Ok(UsefulnessReport { arm_usefulness, non_exhaustiveness_witnesses, arm_intersections }) } -- cgit 1.4.1-3-g733a5 From e4487ad391503fa109506c40aeba377fda0d97dd Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Tue, 5 Mar 2024 00:16:11 +0100 Subject: Improve the `WitnessPat: Debug` impl --- compiler/rustc_pattern_analysis/src/constructor.rs | 75 ++++++++++++++++++++ compiler/rustc_pattern_analysis/src/lib.rs | 3 +- compiler/rustc_pattern_analysis/src/pat.rs | 80 +++------------------- compiler/rustc_pattern_analysis/src/rustc.rs | 7 +- 4 files changed, 89 insertions(+), 76 deletions(-) (limited to 'compiler/rustc_pattern_analysis/src') diff --git a/compiler/rustc_pattern_analysis/src/constructor.rs b/compiler/rustc_pattern_analysis/src/constructor.rs index 5b58d7f43b2..95c5556410d 100644 --- a/compiler/rustc_pattern_analysis/src/constructor.rs +++ b/compiler/rustc_pattern_analysis/src/constructor.rs @@ -819,6 +819,81 @@ impl Constructor { } }) } + + pub(crate) fn fmt_fields( + &self, + f: &mut fmt::Formatter<'_>, + ty: &Cx::Ty, + mut fields: impl Iterator, + ) -> fmt::Result { + let mut first = true; + let mut start_or_continue = |s| { + if first { + first = false; + "" + } else { + s + } + }; + let mut start_or_comma = || start_or_continue(", "); + + match self { + Struct | Variant(_) | UnionField => { + Cx::write_variant_name(f, self, ty)?; + // Without `cx`, we can't know which field corresponds to which, so we can't + // get the names of the fields. Instead we just display everything as a tuple + // struct, which should be good enough. + write!(f, "(")?; + for p in fields { + write!(f, "{}{:?}", start_or_comma(), p)?; + } + write!(f, ")")?; + } + // Note: given the expansion of `&str` patterns done in `expand_pattern`, we should + // be careful to detect strings here. However a string literal pattern will never + // be reported as a non-exhaustiveness witness, so we can ignore this issue. + Ref => { + write!(f, "&{:?}", &fields.next().unwrap())?; + } + Slice(slice) => { + write!(f, "[")?; + match slice.kind { + SliceKind::FixedLen(_) => { + for p in fields { + write!(f, "{}{:?}", start_or_comma(), p)?; + } + } + SliceKind::VarLen(prefix_len, _) => { + for p in fields.by_ref().take(prefix_len) { + write!(f, "{}{:?}", start_or_comma(), p)?; + } + write!(f, "{}..", start_or_comma())?; + for p in fields { + write!(f, "{}{:?}", start_or_comma(), p)?; + } + } + } + write!(f, "]")?; + } + Bool(b) => write!(f, "{b}")?, + // Best-effort, will render signed ranges incorrectly + IntRange(range) => write!(f, "{range:?}")?, + F32Range(lo, hi, end) => write!(f, "{lo}{end}{hi}")?, + F64Range(lo, hi, end) => write!(f, "{lo}{end}{hi}")?, + Str(value) => write!(f, "{value:?}")?, + Opaque(..) => write!(f, "")?, + Or => { + for pat in fields { + write!(f, "{}{:?}", start_or_continue(" | "), pat)?; + } + } + Never => write!(f, "!")?, + Wildcard | Missing | NonExhaustive | Hidden | PrivateUninhabited => { + write!(f, "_ : {:?}", ty)? + } + } + Ok(()) + } } #[derive(Debug, Clone, Copy)] diff --git a/compiler/rustc_pattern_analysis/src/lib.rs b/compiler/rustc_pattern_analysis/src/lib.rs index 5c57c990323..3904959fa0f 100644 --- a/compiler/rustc_pattern_analysis/src/lib.rs +++ b/compiler/rustc_pattern_analysis/src/lib.rs @@ -120,7 +120,8 @@ pub trait PatCx: Sized + fmt::Debug { /// `DeconstructedPat`. Only invoqued when `pat.ctor()` is `Struct | Variant(_) | UnionField`. fn write_variant_name( f: &mut fmt::Formatter<'_>, - pat: &crate::pat::DeconstructedPat, + ctor: &crate::constructor::Constructor, + ty: &Self::Ty, ) -> fmt::Result; /// Raise a bug. diff --git a/compiler/rustc_pattern_analysis/src/pat.rs b/compiler/rustc_pattern_analysis/src/pat.rs index e7eed673c94..5f388ee9f89 100644 --- a/compiler/rustc_pattern_analysis/src/pat.rs +++ b/compiler/rustc_pattern_analysis/src/pat.rs @@ -138,81 +138,11 @@ impl DeconstructedPat { /// This is best effort and not good enough for a `Display` impl. impl fmt::Debug for DeconstructedPat { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - let pat = self; - let mut first = true; - let mut start_or_continue = |s| { - if first { - first = false; - "" - } else { - s - } - }; - let mut start_or_comma = || start_or_continue(", "); - let mut fields: Vec<_> = (0..self.arity).map(|_| PatOrWild::Wild).collect(); for ipat in self.iter_fields() { fields[ipat.idx] = PatOrWild::Pat(&ipat.pat); } - - match pat.ctor() { - Struct | Variant(_) | UnionField => { - Cx::write_variant_name(f, pat)?; - // Without `cx`, we can't know which field corresponds to which, so we can't - // get the names of the fields. Instead we just display everything as a tuple - // struct, which should be good enough. - write!(f, "(")?; - for p in fields { - write!(f, "{}", start_or_comma())?; - write!(f, "{p:?}")?; - } - write!(f, ")") - } - // Note: given the expansion of `&str` patterns done in `expand_pattern`, we should - // be careful to detect strings here. However a string literal pattern will never - // be reported as a non-exhaustiveness witness, so we can ignore this issue. - Ref => { - write!(f, "&{:?}", &fields[0]) - } - Slice(slice) => { - write!(f, "[")?; - match slice.kind { - SliceKind::FixedLen(_) => { - for p in fields { - write!(f, "{}{:?}", start_or_comma(), p)?; - } - } - SliceKind::VarLen(prefix_len, _) => { - for p in &fields[..prefix_len] { - write!(f, "{}{:?}", start_or_comma(), p)?; - } - write!(f, "{}", start_or_comma())?; - write!(f, "..")?; - for p in &fields[prefix_len..] { - write!(f, "{}{:?}", start_or_comma(), p)?; - } - } - } - write!(f, "]") - } - Bool(b) => write!(f, "{b}"), - // Best-effort, will render signed ranges incorrectly - IntRange(range) => write!(f, "{range:?}"), - F32Range(lo, hi, end) => write!(f, "{lo}{end}{hi}"), - F64Range(lo, hi, end) => write!(f, "{lo}{end}{hi}"), - Str(value) => write!(f, "{value:?}"), - Opaque(..) => write!(f, ""), - Or => { - for pat in fields { - write!(f, "{}{:?}", start_or_continue(" | "), pat)?; - } - Ok(()) - } - Never => write!(f, "!"), - Wildcard | Missing | NonExhaustive | Hidden | PrivateUninhabited => { - write!(f, "_ : {:?}", pat.ty()) - } - } + self.ctor().fmt_fields(f, self.ty(), fields.into_iter()) } } @@ -295,7 +225,6 @@ impl<'p, Cx: PatCx> fmt::Debug for PatOrWild<'p, Cx> { /// Same idea as `DeconstructedPat`, except this is a fictitious pattern built up for diagnostics /// purposes. As such they don't use interning and can be cloned. -#[derive(Debug)] pub struct WitnessPat { ctor: Constructor, pub(crate) fields: Vec>, @@ -353,3 +282,10 @@ impl WitnessPat { self.fields.iter() } } + +/// This is best effort and not good enough for a `Display` impl. +impl fmt::Debug for WitnessPat { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.ctor().fmt_fields(f, self.ty(), self.fields.iter()) + } +} diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs index eedc00a5613..f600c20d384 100644 --- a/compiler/rustc_pattern_analysis/src/rustc.rs +++ b/compiler/rustc_pattern_analysis/src/rustc.rs @@ -874,13 +874,14 @@ impl<'p, 'tcx: 'p> PatCx for RustcPatCtxt<'p, 'tcx> { fn write_variant_name( f: &mut fmt::Formatter<'_>, - pat: &crate::pat::DeconstructedPat, + ctor: &crate::constructor::Constructor, + ty: &Self::Ty, ) -> fmt::Result { - if let ty::Adt(adt, _) = pat.ty().kind() { + if let ty::Adt(adt, _) = ty.kind() { if adt.is_box() { write!(f, "Box")? } else { - let variant = adt.variant(Self::variant_index_for_adt(pat.ctor(), *adt)); + let variant = adt.variant(Self::variant_index_for_adt(ctor, *adt)); write!(f, "{}", variant.name)?; } } -- cgit 1.4.1-3-g733a5 From d697dd44d18fbab9a28032d7b1ceba829600637e Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Mon, 4 Mar 2024 16:57:32 +0100 Subject: Add a crate-custom test harness --- Cargo.lock | 2 + compiler/rustc_pattern_analysis/Cargo.toml | 4 + compiler/rustc_pattern_analysis/src/lib.rs | 6 + .../rustc_pattern_analysis/tests/common/mod.rs | 315 +++++++++++++++++++++ .../rustc_pattern_analysis/tests/complexity.rs | 109 +++++++ .../rustc_pattern_analysis/tests/exhaustiveness.rs | 77 +++++ .../rustc_pattern_analysis/tests/intersection.rs | 69 +++++ 7 files changed, 582 insertions(+) create mode 100644 compiler/rustc_pattern_analysis/tests/common/mod.rs create mode 100644 compiler/rustc_pattern_analysis/tests/complexity.rs create mode 100644 compiler/rustc_pattern_analysis/tests/exhaustiveness.rs create mode 100644 compiler/rustc_pattern_analysis/tests/intersection.rs (limited to 'compiler/rustc_pattern_analysis/src') diff --git a/Cargo.lock b/Cargo.lock index 3110f32ade9..0b9eb88ec2b 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -4440,6 +4440,8 @@ dependencies = [ "rustc_target", "smallvec", "tracing", + "tracing-subscriber", + "tracing-tree", ] [[package]] diff --git a/compiler/rustc_pattern_analysis/Cargo.toml b/compiler/rustc_pattern_analysis/Cargo.toml index b9bdcb41929..6357d18b9da 100644 --- a/compiler/rustc_pattern_analysis/Cargo.toml +++ b/compiler/rustc_pattern_analysis/Cargo.toml @@ -22,6 +22,10 @@ smallvec = { version = "1.8.1", features = ["union"] } tracing = "0.1" # tidy-alphabetical-end +[dev-dependencies] +tracing-subscriber = { version = "0.3.3", default-features = false, features = ["fmt", "env-filter", "ansi"] } +tracing-tree = "0.2.0" + [features] default = ["rustc"] rustc = [ diff --git a/compiler/rustc_pattern_analysis/src/lib.rs b/compiler/rustc_pattern_analysis/src/lib.rs index 3904959fa0f..1a1da5c55f6 100644 --- a/compiler/rustc_pattern_analysis/src/lib.rs +++ b/compiler/rustc_pattern_analysis/src/lib.rs @@ -49,6 +49,12 @@ pub mod index { } } + impl FromIterator for IdxContainer { + fn from_iter>(iter: T) -> Self { + Self(iter.into_iter().enumerate().collect()) + } + } + #[derive(Debug)] pub struct IdxSet(pub rustc_hash::FxHashSet); impl IdxSet { diff --git a/compiler/rustc_pattern_analysis/tests/common/mod.rs b/compiler/rustc_pattern_analysis/tests/common/mod.rs new file mode 100644 index 00000000000..e72fddb9e9a --- /dev/null +++ b/compiler/rustc_pattern_analysis/tests/common/mod.rs @@ -0,0 +1,315 @@ +use rustc_pattern_analysis::{ + constructor::{ + Constructor, ConstructorSet, IntRange, MaybeInfiniteInt, RangeEnd, VariantVisibility, + }, + usefulness::{PlaceValidity, UsefulnessReport}, + Captures, MatchArm, PatCx, PrivateUninhabitedField, +}; + +/// Sets up `tracing` for easier debugging. Tries to look like the `rustc` setup. +pub fn init_tracing() { + use tracing_subscriber::layer::SubscriberExt; + use tracing_subscriber::util::SubscriberInitExt; + use tracing_subscriber::Layer; + let _ = tracing_tree::HierarchicalLayer::default() + .with_writer(std::io::stderr) + .with_indent_lines(true) + .with_ansi(true) + .with_targets(true) + .with_indent_amount(2) + .with_subscriber( + tracing_subscriber::Registry::default() + .with(tracing_subscriber::EnvFilter::from_default_env()), + ) + .try_init(); +} + +/// A simple set of types. +#[allow(dead_code)] +#[derive(Debug, Copy, Clone)] +pub enum Ty { + /// Booleans + Bool, + /// 8-bit unsigned integers + U8, + /// Tuples. + Tuple(&'static [Ty]), + /// A struct with `arity` fields of type `ty`. + BigStruct { arity: usize, ty: &'static Ty }, + /// A enum with `arity` variants of type `ty`. + BigEnum { arity: usize, ty: &'static Ty }, +} + +/// The important logic. +impl Ty { + pub fn sub_tys(&self, ctor: &Constructor) -> Vec { + use Constructor::*; + match (ctor, *self) { + (Struct, Ty::Tuple(tys)) => tys.iter().copied().collect(), + (Struct, Ty::BigStruct { arity, ty }) => (0..arity).map(|_| *ty).collect(), + (Variant(_), Ty::BigEnum { ty, .. }) => vec![*ty], + (Bool(..) | IntRange(..) | NonExhaustive | Missing | Wildcard, _) => vec![], + _ => panic!("Unexpected ctor {ctor:?} for type {self:?}"), + } + } + + pub fn ctor_set(&self) -> ConstructorSet { + match *self { + Ty::Bool => ConstructorSet::Bool, + Ty::U8 => ConstructorSet::Integers { + range_1: IntRange::from_range( + MaybeInfiniteInt::new_finite_uint(0), + MaybeInfiniteInt::new_finite_uint(255), + RangeEnd::Included, + ), + range_2: None, + }, + Ty::Tuple(..) | Ty::BigStruct { .. } => ConstructorSet::Struct { empty: false }, + Ty::BigEnum { arity, .. } => ConstructorSet::Variants { + variants: (0..arity).map(|_| VariantVisibility::Visible).collect(), + non_exhaustive: false, + }, + } + } + + pub fn write_variant_name( + &self, + f: &mut std::fmt::Formatter<'_>, + ctor: &Constructor, + ) -> std::fmt::Result { + match (*self, ctor) { + (Ty::Tuple(..), _) => Ok(()), + (Ty::BigStruct { .. }, _) => write!(f, "BigStruct"), + (Ty::BigEnum { .. }, Constructor::Variant(i)) => write!(f, "BigEnum::Variant{i}"), + _ => write!(f, "{:?}::{:?}", self, ctor), + } + } +} + +/// Compute usefulness in our simple context (and set up tracing for easier debugging). +pub fn compute_match_usefulness<'p>( + arms: &[MatchArm<'p, Cx>], + ty: Ty, + scrut_validity: PlaceValidity, + complexity_limit: Option, +) -> Result, ()> { + init_tracing(); + rustc_pattern_analysis::usefulness::compute_match_usefulness( + &Cx, + arms, + ty, + scrut_validity, + complexity_limit, + ) +} + +#[derive(Debug)] +pub struct Cx; + +/// The context for pattern analysis. Forwards anything interesting to `Ty` methods. +impl PatCx for Cx { + type Ty = Ty; + type Error = (); + type VariantIdx = usize; + type StrLit = (); + type ArmData = (); + type PatData = (); + + fn is_exhaustive_patterns_feature_on(&self) -> bool { + false + } + + fn is_min_exhaustive_patterns_feature_on(&self) -> bool { + false + } + + fn ctor_arity(&self, ctor: &Constructor, ty: &Self::Ty) -> usize { + ty.sub_tys(ctor).len() + } + + fn ctor_sub_tys<'a>( + &'a self, + ctor: &'a Constructor, + ty: &'a Self::Ty, + ) -> impl Iterator + ExactSizeIterator + Captures<'a> + { + ty.sub_tys(ctor).into_iter().map(|ty| (ty, PrivateUninhabitedField(false))) + } + + fn ctors_for_ty(&self, ty: &Self::Ty) -> Result, Self::Error> { + Ok(ty.ctor_set()) + } + + fn write_variant_name( + f: &mut std::fmt::Formatter<'_>, + ctor: &Constructor, + ty: &Self::Ty, + ) -> std::fmt::Result { + ty.write_variant_name(f, ctor) + } + + fn bug(&self, fmt: std::fmt::Arguments<'_>) -> Self::Error { + panic!("{}", fmt) + } + + /// Abort when reaching the complexity limit. This is what we'll check in tests. + fn complexity_exceeded(&self) -> Result<(), Self::Error> { + Err(()) + } +} + +/// Construct a single pattern; see `pats!()`. +#[allow(unused_macros)] +macro_rules! pat { + ($($rest:tt)*) => {{ + let mut vec = pats!($($rest)*); + vec.pop().unwrap() + }}; +} + +/// A macro to construct patterns. Called like `pats!(type_expr; pattern, pattern, ..)` and returns +/// a `Vec`. A pattern can be nested and looks like `Constructor(pat, pat)` or +/// `Constructor { .i: pat, .j: pat }`, where `Constructor` is `Struct`, `Variant.i` (with index +/// `i`), as well as booleans and integer ranges. +/// +/// The general structure of the macro is a tt-muncher with several stages identified with +/// `@something(args)`. The args are a key-value list (the keys ensure we don't mix the arguments +/// around) which is passed down and modified as needed. We then parse token-trees from +/// left-to-right. Non-trivial recursion happens when we parse the arguments to a pattern: we +/// recurse to parse the tokens inside `{..}`/`(..)`, and then we continue parsing anything that +/// follows. +macro_rules! pats { + // Entrypoint + // Parse `type; ..` + ($ty:expr; $($rest:tt)*) => {{ + #[allow(unused_imports)] + use rustc_pattern_analysis::{ + constructor::{Constructor, IntRange, MaybeInfiniteInt, RangeEnd}, + pat::DeconstructedPat, + }; + let ty = $ty; + // The heart of the macro is designed to push `IndexedPat`s into a `Vec`, so we work around + // that. + let sub_tys = ::std::iter::repeat(&ty); + let mut vec = Vec::new(); + pats!(@ctor(vec:vec, sub_tys:sub_tys, idx:0) $($rest)*); + vec.into_iter().map(|ipat| ipat.pat).collect::>() + }}; + + // Parse `constructor ..` + + (@ctor($($args:tt)*) true $($rest:tt)*) => {{ + let ctor = Constructor::Bool(true); + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + (@ctor($($args:tt)*) false $($rest:tt)*) => {{ + let ctor = Constructor::Bool(false); + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + (@ctor($($args:tt)*) Struct $($rest:tt)*) => {{ + let ctor = Constructor::Struct; + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + (@ctor($($args:tt)*) ( $($fields:tt)* ) $($rest:tt)*) => {{ + let ctor = Constructor::Struct; // tuples + pats!(@pat($($args)*, ctor:ctor) ( $($fields)* ) $($rest)*) + }}; + (@ctor($($args:tt)*) Variant.$variant:ident $($rest:tt)*) => {{ + let ctor = Constructor::Variant($variant); + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + (@ctor($($args:tt)*) Variant.$variant:literal $($rest:tt)*) => {{ + let ctor = Constructor::Variant($variant); + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + (@ctor($($args:tt)*) _ $($rest:tt)*) => {{ + let ctor = Constructor::Wildcard; + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + + // Integers and int ranges + (@ctor($($args:tt)*) $($start:literal)?..$end:literal $($rest:tt)*) => {{ + let ctor = Constructor::IntRange(IntRange::from_range( + pats!(@rangeboundary- $($start)?), + pats!(@rangeboundary+ $end), + RangeEnd::Excluded, + )); + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + (@ctor($($args:tt)*) $($start:literal)?.. $($rest:tt)*) => {{ + let ctor = Constructor::IntRange(IntRange::from_range( + pats!(@rangeboundary- $($start)?), + pats!(@rangeboundary+), + RangeEnd::Excluded, + )); + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + (@ctor($($args:tt)*) $($start:literal)?..=$end:literal $($rest:tt)*) => {{ + let ctor = Constructor::IntRange(IntRange::from_range( + pats!(@rangeboundary- $($start)?), + pats!(@rangeboundary+ $end), + RangeEnd::Included, + )); + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + (@ctor($($args:tt)*) $int:literal $($rest:tt)*) => {{ + let ctor = Constructor::IntRange(IntRange::from_range( + pats!(@rangeboundary- $int), + pats!(@rangeboundary+ $int), + RangeEnd::Included, + )); + pats!(@pat($($args)*, ctor:ctor) $($rest)*) + }}; + // Utility to manage range boundaries. + (@rangeboundary $sign:tt $int:literal) => { MaybeInfiniteInt::new_finite_uint($int) }; + (@rangeboundary -) => { MaybeInfiniteInt::NegInfinity }; + (@rangeboundary +) => { MaybeInfiniteInt::PosInfinity }; + + // Parse subfields: `(..)` or `{..}` + + // Constructor with no fields, e.g. `bool` or `Variant.1`. + (@pat($($args:tt)*) $(,)?) => { + pats!(@pat($($args)*) {}) + }; + (@pat($($args:tt)*) , $($rest:tt)*) => { + pats!(@pat($($args)*) {}, $($rest)*) + }; + // `(..)` and `{..}` are treated the same. + (@pat($($args:tt)*) ( $($subpat:tt)* ) $($rest:tt)*) => {{ + pats!(@pat($($args)*) { $($subpat)* } $($rest)*) + }}; + (@pat(vec:$vec:expr, sub_tys:$sub_tys:expr, idx:$idx:expr, ctor:$ctor:expr) { $($fields:tt)* } $($rest:tt)*) => {{ + let sub_tys = $sub_tys; + let index = $idx; + // Silly dance to work with both a vec and `iter::repeat()`. + let ty = *(&sub_tys).clone().into_iter().nth(index).unwrap(); + let ctor = $ctor; + let ctor_sub_tys = &ty.sub_tys(&ctor); + #[allow(unused_mut)] + let mut fields = Vec::new(); + // Parse subpatterns (note the leading comma). + pats!(@fields(idx:0, vec:fields, sub_tys:ctor_sub_tys) ,$($fields)*); + let arity = ctor_sub_tys.len(); + let pat = DeconstructedPat::new(ctor, fields, arity, ty, ()).at_index(index); + $vec.push(pat); + + // Continue parsing further patterns. + pats!(@fields(idx:index+1, vec:$vec, sub_tys:sub_tys) $($rest)*); + }}; + + // Parse fields one by one. + + // No fields left. + (@fields($($args:tt)*) $(,)?) => {}; + // `.i: pat` sets the current index to `i`. + (@fields(idx:$_idx:expr, $($args:tt)*) , .$idx:literal : $($rest:tt)*) => {{ + pats!(@ctor($($args)*, idx:$idx) $($rest)*); + }}; + (@fields(idx:$_idx:expr, $($args:tt)*) , .$idx:ident : $($rest:tt)*) => {{ + pats!(@ctor($($args)*, idx:$idx) $($rest)*); + }}; + // Field without an explicit index; we use the current index which gets incremented above. + (@fields(idx:$idx:expr, $($args:tt)*) , $($rest:tt)*) => {{ + pats!(@ctor($($args)*, idx:$idx) $($rest)*); + }}; +} diff --git a/compiler/rustc_pattern_analysis/tests/complexity.rs b/compiler/rustc_pattern_analysis/tests/complexity.rs new file mode 100644 index 00000000000..93f455c6257 --- /dev/null +++ b/compiler/rustc_pattern_analysis/tests/complexity.rs @@ -0,0 +1,109 @@ +//! Test the pattern complexity limit. +use common::*; +use rustc_pattern_analysis::{pat::DeconstructedPat, usefulness::PlaceValidity, MatchArm}; + +#[macro_use] +mod common; + +/// Analyze a match made of these patterns. Ignore the report; we only care whether we exceeded the +/// limit or not. +fn check(patterns: &[DeconstructedPat], complexity_limit: usize) -> Result<(), ()> { + let ty = *patterns[0].ty(); + let arms: Vec<_> = + patterns.iter().map(|pat| MatchArm { pat, has_guard: false, arm_data: () }).collect(); + compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, Some(complexity_limit)) + .map(|_report| ()) +} + +/// Asserts that analyzing this match takes exactly `complexity` steps. +#[track_caller] +fn assert_complexity(patterns: Vec>, complexity: usize) { + assert!(check(&patterns, complexity).is_ok()); + assert!(check(&patterns, complexity - 1).is_err()); +} + +/// Construct a match like: +/// ```ignore(illustrative) +/// match ... { +/// BigStruct { field01: true, .. } => {} +/// BigStruct { field02: true, .. } => {} +/// BigStruct { field03: true, .. } => {} +/// BigStruct { field04: true, .. } => {} +/// ... +/// _ => {} +/// } +/// ``` +fn diagonal_match(arity: usize) -> Vec> { + let struct_ty = Ty::BigStruct { arity, ty: &Ty::Bool }; + let mut patterns = vec![]; + for i in 0..arity { + patterns.push(pat!(struct_ty; Struct { .i: true })); + } + patterns.push(pat!(struct_ty; _)); + patterns +} + +/// Construct a match like: +/// ```ignore(illustrative) +/// match ... { +/// BigStruct { field01: true, .. } => {} +/// BigStruct { field02: true, .. } => {} +/// BigStruct { field03: true, .. } => {} +/// BigStruct { field04: true, .. } => {} +/// ... +/// BigStruct { field01: false, .. } => {} +/// BigStruct { field02: false, .. } => {} +/// BigStruct { field03: false, .. } => {} +/// BigStruct { field04: false, .. } => {} +/// ... +/// _ => {} +/// } +/// ``` +fn diagonal_exponential_match(arity: usize) -> Vec> { + let struct_ty = Ty::BigStruct { arity, ty: &Ty::Bool }; + let mut patterns = vec![]; + for i in 0..arity { + patterns.push(pat!(struct_ty; Struct { .i: true })); + } + for i in 0..arity { + patterns.push(pat!(struct_ty; Struct { .i: false })); + } + patterns.push(pat!(struct_ty; _)); + patterns +} + +#[test] +fn test_diagonal_struct_match() { + // These cases are nicely linear: we check `arity` patterns with exactly one `true`, matching + // in 2 branches each, and a final pattern with all `false`, matching only the `_` branch. + assert_complexity(diagonal_match(20), 41); + assert_complexity(diagonal_match(30), 61); + // This case goes exponential. + assert!(check(&diagonal_exponential_match(10), 10000).is_err()); +} + +/// Construct a match like: +/// ```ignore(illustrative) +/// match ... { +/// BigEnum::Variant1(_) => {} +/// BigEnum::Variant2(_) => {} +/// BigEnum::Variant3(_) => {} +/// ... +/// _ => {} +/// } +/// ``` +fn big_enum(arity: usize) -> Vec> { + let enum_ty = Ty::BigEnum { arity, ty: &Ty::Bool }; + let mut patterns = vec![]; + for i in 0..arity { + patterns.push(pat!(enum_ty; Variant.i)); + } + patterns.push(pat!(enum_ty; _)); + patterns +} + +#[test] +fn test_big_enum() { + // We try 2 branches per variant. + assert_complexity(big_enum(20), 40); +} diff --git a/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs b/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs new file mode 100644 index 00000000000..4c6c72fa8ec --- /dev/null +++ b/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs @@ -0,0 +1,77 @@ +//! Test exhaustiveness checking. +use common::*; +use rustc_pattern_analysis::{ + pat::{DeconstructedPat, WitnessPat}, + usefulness::PlaceValidity, + MatchArm, +}; + +#[macro_use] +mod common; + +/// Analyze a match made of these patterns. +fn check(patterns: Vec>) -> Vec> { + let ty = *patterns[0].ty(); + let arms: Vec<_> = + patterns.iter().map(|pat| MatchArm { pat, has_guard: false, arm_data: () }).collect(); + let report = + compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, None).unwrap(); + report.non_exhaustiveness_witnesses +} + +#[track_caller] +fn assert_exhaustive(patterns: Vec>) { + let witnesses = check(patterns); + if !witnesses.is_empty() { + panic!("non-exaustive match: missing {witnesses:?}"); + } +} + +#[track_caller] +fn assert_non_exhaustive(patterns: Vec>) { + let witnesses = check(patterns); + assert!(!witnesses.is_empty()) +} + +#[test] +fn test_int_ranges() { + let ty = Ty::U8; + assert_exhaustive(pats!(ty; + 0..=255, + )); + assert_exhaustive(pats!(ty; + 0.., + )); + assert_non_exhaustive(pats!(ty; + 0..255, + )); + assert_exhaustive(pats!(ty; + 0..255, + 255, + )); + assert_exhaustive(pats!(ty; + ..10, + 10.. + )); +} + +#[test] +fn test_nested() { + let ty = Ty::BigStruct { arity: 2, ty: &Ty::BigEnum { arity: 2, ty: &Ty::Bool } }; + assert_non_exhaustive(pats!(ty; + Struct(Variant.0, _), + )); + assert_exhaustive(pats!(ty; + Struct(Variant.0, _), + Struct(Variant.1, _), + )); + assert_non_exhaustive(pats!(ty; + Struct(Variant.0, _), + Struct(_, Variant.0), + )); + assert_exhaustive(pats!(ty; + Struct(Variant.0, _), + Struct(_, Variant.0), + Struct(Variant.1, Variant.1), + )); +} diff --git a/compiler/rustc_pattern_analysis/tests/intersection.rs b/compiler/rustc_pattern_analysis/tests/intersection.rs new file mode 100644 index 00000000000..4d8a21506d7 --- /dev/null +++ b/compiler/rustc_pattern_analysis/tests/intersection.rs @@ -0,0 +1,69 @@ +//! Test the computation of arm intersections. +use common::*; +use rustc_pattern_analysis::{pat::DeconstructedPat, usefulness::PlaceValidity, MatchArm}; + +#[macro_use] +mod common; + +/// Analyze a match made of these patterns and returns the computed arm intersections. +fn check(patterns: Vec>) -> Vec> { + let ty = *patterns[0].ty(); + let arms: Vec<_> = + patterns.iter().map(|pat| MatchArm { pat, has_guard: false, arm_data: () }).collect(); + let report = + compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, None).unwrap(); + report.arm_intersections.into_iter().map(|bitset| bitset.iter().collect()).collect() +} + +#[track_caller] +fn assert_intersects(patterns: Vec>, intersects: &[&[usize]]) { + let computed_intersects = check(patterns); + assert_eq!(computed_intersects, intersects); +} + +#[test] +fn test_int_ranges() { + let ty = Ty::U8; + assert_intersects( + pats!(ty; + 0..=100, + 100.., + ), + &[&[], &[0]], + ); + assert_intersects( + pats!(ty; + 0..=101, + 100.., + ), + &[&[], &[0]], + ); + assert_intersects( + pats!(ty; + 0..100, + 100.., + ), + &[&[], &[]], + ); +} + +#[test] +fn test_nested() { + let ty = Ty::Tuple(&[Ty::Bool; 2]); + assert_intersects( + pats!(ty; + (true, true), + (true, _), + (_, true), + ), + &[&[], &[0], &[0, 1]], + ); + // Here we shortcut because `(true, true)` is irrelevant, so we fail to detect the intersection. + assert_intersects( + pats!(ty; + (true, _), + (_, true), + ), + &[&[], &[]], + ); +} -- cgit 1.4.1-3-g733a5 From 120d3570aa467c287814fe3edb9003920d8232aa Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Fri, 8 Mar 2024 19:17:23 +0100 Subject: Add barest-bones deref patterns Co-authored-by: Deadbeef --- compiler/rustc_ast_passes/src/feature_gate.rs | 10 +++++-- compiler/rustc_feature/src/unstable.rs | 2 ++ compiler/rustc_hir_typeck/src/pat.rs | 28 +++++++++++++++++-- compiler/rustc_middle/src/thir.rs | 9 +++++++ compiler/rustc_middle/src/thir/visit.rs | 1 + compiler/rustc_mir_build/src/build/matches/mod.rs | 4 +++ compiler/rustc_mir_build/src/build/matches/util.rs | 6 +++++ compiler/rustc_mir_build/src/check_unsafety.rs | 3 ++- compiler/rustc_mir_build/src/thir/pattern/mod.rs | 3 +++ compiler/rustc_mir_build/src/thir/print.rs | 6 +++++ compiler/rustc_pattern_analysis/src/rustc.rs | 6 +++++ compiler/rustc_span/src/symbol.rs | 1 + tests/ui/cfg/cfg-false-feature.stderr | 24 ++++++++--------- .../feature-gates/feature-gate-deref_patterns.rs | 9 +++++++ .../feature-gate-deref_patterns.stderr | 13 +++++++++ tests/ui/pattern/deref-patterns/typeck.rs | 31 ++++++++++++++++++++++ 16 files changed, 139 insertions(+), 17 deletions(-) create mode 100644 tests/ui/feature-gates/feature-gate-deref_patterns.rs create mode 100644 tests/ui/feature-gates/feature-gate-deref_patterns.stderr create mode 100644 tests/ui/pattern/deref-patterns/typeck.rs (limited to 'compiler/rustc_pattern_analysis/src') diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs index 2c396a64789..277e82b4e53 100644 --- a/compiler/rustc_ast_passes/src/feature_gate.rs +++ b/compiler/rustc_ast_passes/src/feature_gate.rs @@ -413,7 +413,10 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> { } } PatKind::Box(..) => { - gate!(&self, box_patterns, pattern.span, "box pattern syntax is experimental"); + if !self.features.deref_patterns { + // Allow box patterns under `deref_patterns`. + gate!(&self, box_patterns, pattern.span, "box pattern syntax is experimental"); + } } PatKind::Range(_, Some(_), Spanned { node: RangeEnd::Excluded, .. }) => { gate!( @@ -607,13 +610,16 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) { }; } + if !visitor.features.deref_patterns { + // Allow box patterns under `deref_patterns`. + gate_all_legacy_dont_use!(box_patterns, "box pattern syntax is experimental"); + } gate_all_legacy_dont_use!(trait_alias, "trait aliases are experimental"); // Despite being a new feature, `where T: Trait`, which is RTN syntax now, // used to be gated under associated_type_bounds, which are right above, so RTN needs to // be too. gate_all_legacy_dont_use!(return_type_notation, "return type notation is experimental"); gate_all_legacy_dont_use!(decl_macro, "`macro` is experimental"); - gate_all_legacy_dont_use!(box_patterns, "box pattern syntax is experimental"); gate_all_legacy_dont_use!( exclusive_range_pattern, "exclusive range pattern syntax is experimental" diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs index a3b13c4d907..1820e172ea5 100644 --- a/compiler/rustc_feature/src/unstable.rs +++ b/compiler/rustc_feature/src/unstable.rs @@ -436,6 +436,8 @@ declare_features! ( (unstable, deprecated_safe, "1.61.0", Some(94978)), /// Allows having using `suggestion` in the `#[deprecated]` attribute. (unstable, deprecated_suggestion, "1.61.0", Some(94785)), + /// Allows deref patterns. + (incomplete, deref_patterns, "CURRENT_RUSTC_VERSION", Some(87121)), /// Controls errors in trait implementations. (unstable, do_not_recommend, "1.67.0", Some(51992)), /// Tells rustdoc to automatically generate `#[doc(cfg(...))]`. diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs index 491da7eb2c2..633f851c7d5 100644 --- a/compiler/rustc_hir_typeck/src/pat.rs +++ b/compiler/rustc_hir_typeck/src/pat.rs @@ -18,8 +18,7 @@ use rustc_span::edit_distance::find_best_match_for_name; use rustc_span::hygiene::DesugaringKind; use rustc_span::source_map::Spanned; use rustc_span::symbol::{kw, sym, Ident}; -use rustc_span::Span; -use rustc_span::{BytePos, DUMMY_SP}; +use rustc_span::{BytePos, Span, DUMMY_SP}; use rustc_target::abi::FieldIdx; use rustc_trait_selection::traits::{ObligationCause, Pattern}; use ty::VariantDef; @@ -211,6 +210,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { PatKind::Tuple(elements, ddpos) => { self.check_pat_tuple(pat.span, elements, ddpos, expected, pat_info) } + PatKind::Box(inner) if self.tcx.features().deref_patterns => { + self.check_pat_deref(pat.span, inner, expected, pat_info) + } PatKind::Box(inner) => self.check_pat_box(pat.span, inner, expected, pat_info), PatKind::Ref(inner, mutbl) => self.check_pat_ref(pat, inner, mutbl, expected, pat_info), PatKind::Slice(before, slice, after) => { @@ -1975,6 +1977,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { box_ty } + fn check_pat_deref( + &self, + span: Span, + inner: &'tcx Pat<'tcx>, + expected: Ty<'tcx>, + pat_info: PatInfo<'tcx, '_>, + ) -> Ty<'tcx> { + let tcx = self.tcx; + // FIXME(deref_patterns): use `DerefPure` for soundness + // FIXME(deref_patterns): use `DerefMut` when required + // ::Target + let ty = Ty::new_projection( + tcx, + tcx.require_lang_item(hir::LangItem::DerefTarget, Some(span)), + [expected], + ); + let ty = self.normalize(span, ty); + let ty = self.try_structurally_resolve_type(span, ty); + self.check_pat(inner, ty, pat_info); + expected + } + // Precondition: Pat is Ref(inner) fn check_pat_ref( &self, diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs index 96a61883cc1..fc9950a51fb 100644 --- a/compiler/rustc_middle/src/thir.rs +++ b/compiler/rustc_middle/src/thir.rs @@ -647,6 +647,7 @@ impl<'tcx> Pat<'tcx> { AscribeUserType { subpattern, .. } | Binding { subpattern: Some(subpattern), .. } | Deref { subpattern } + | DerefPattern { subpattern } | InlineConstant { subpattern, .. } => subpattern.walk_(it), Leaf { subpatterns } | Variant { subpatterns, .. } => { subpatterns.iter().for_each(|field| field.pattern.walk_(it)) @@ -762,6 +763,11 @@ pub enum PatKind<'tcx> { subpattern: Box>, }, + /// Deref pattern, written `box P` for now. + DerefPattern { + subpattern: Box>, + }, + /// One of the following: /// * `&str` (represented as a valtree), which will be handled as a string pattern and thus /// exhaustiveness checking will detect if you use the same string twice in different @@ -1172,6 +1178,9 @@ impl<'tcx> fmt::Display for Pat<'tcx> { } write!(f, "{subpattern}") } + PatKind::DerefPattern { ref subpattern } => { + write!(f, "k#deref {subpattern}") + } PatKind::Constant { value } => write!(f, "{value}"), PatKind::InlineConstant { def: _, ref subpattern } => { write!(f, "{} (from inline const)", subpattern) diff --git a/compiler/rustc_middle/src/thir/visit.rs b/compiler/rustc_middle/src/thir/visit.rs index 5952c296fb6..99ab006bcc0 100644 --- a/compiler/rustc_middle/src/thir/visit.rs +++ b/compiler/rustc_middle/src/thir/visit.rs @@ -229,6 +229,7 @@ pub fn walk_pat<'thir, 'tcx: 'thir, V: Visitor<'thir, 'tcx>>( match &pat.kind { AscribeUserType { subpattern, ascription: _ } | Deref { subpattern } + | DerefPattern { subpattern } | Binding { subpattern: Some(subpattern), mutability: _, diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs index d2cbbf9be32..f4f452d474f 100644 --- a/compiler/rustc_mir_build/src/build/matches/mod.rs +++ b/compiler/rustc_mir_build/src/build/matches/mod.rs @@ -879,6 +879,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { self.visit_primary_bindings(subpattern, pattern_user_ty.deref(), f); } + PatKind::DerefPattern { ref subpattern } => { + self.visit_primary_bindings(subpattern, UserTypeProjections::none(), f); + } + PatKind::AscribeUserType { ref subpattern, ascription: thir::Ascription { ref annotation, variance: _ }, diff --git a/compiler/rustc_mir_build/src/build/matches/util.rs b/compiler/rustc_mir_build/src/build/matches/util.rs index d0d49c13f13..1148cd19a01 100644 --- a/compiler/rustc_mir_build/src/build/matches/util.rs +++ b/compiler/rustc_mir_build/src/build/matches/util.rs @@ -256,6 +256,12 @@ impl<'pat, 'tcx> MatchPair<'pat, 'tcx> { subpairs.push(MatchPair::new(place_builder, subpattern, cx)); default_irrefutable() } + + PatKind::DerefPattern { .. } => { + // FIXME(deref_patterns) + // Treat it like a wildcard for now. + default_irrefutable() + } }; MatchPair { place, test_case, subpairs, pattern } diff --git a/compiler/rustc_mir_build/src/check_unsafety.rs b/compiler/rustc_mir_build/src/check_unsafety.rs index 1ce8da162bf..e04fe31a76f 100644 --- a/compiler/rustc_mir_build/src/check_unsafety.rs +++ b/compiler/rustc_mir_build/src/check_unsafety.rs @@ -250,6 +250,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> { | PatKind::Variant { .. } | PatKind::Leaf { .. } | PatKind::Deref { .. } + | PatKind::DerefPattern { .. } | PatKind::Range { .. } | PatKind::Slice { .. } | PatKind::Array { .. } => { @@ -310,7 +311,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> { } visit::walk_pat(self, pat); } - PatKind::Deref { .. } => { + PatKind::Deref { .. } | PatKind::DerefPattern { .. } => { let old_inside_adt = std::mem::replace(&mut self.inside_adt, false); visit::walk_pat(self, pat); self.inside_adt = old_inside_adt; diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs index 03eda9a9322..f4aed91cd72 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs @@ -257,6 +257,9 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { return self.lower_path(qpath, pat.hir_id, pat.span); } + hir::PatKind::Box(subpattern) if self.tcx.features().deref_patterns => { + PatKind::DerefPattern { subpattern: self.lower_pattern(subpattern) } + } hir::PatKind::Ref(subpattern, _) | hir::PatKind::Box(subpattern) => { PatKind::Deref { subpattern: self.lower_pattern(subpattern) } } diff --git a/compiler/rustc_mir_build/src/thir/print.rs b/compiler/rustc_mir_build/src/thir/print.rs index d53704f89e7..16c4248a159 100644 --- a/compiler/rustc_mir_build/src/thir/print.rs +++ b/compiler/rustc_mir_build/src/thir/print.rs @@ -688,6 +688,12 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> { self.print_pat(subpattern, depth_lvl + 2); print_indented!(self, "}", depth_lvl + 1); } + PatKind::DerefPattern { subpattern } => { + print_indented!(self, "DerefPattern { ", depth_lvl + 1); + print_indented!(self, "subpattern:", depth_lvl + 2); + self.print_pat(subpattern, depth_lvl + 2); + print_indented!(self, "}", depth_lvl + 1); + } PatKind::Constant { value } => { print_indented!(self, "Constant {", depth_lvl + 1); print_indented!(self, format!("value: {:?}", value), depth_lvl + 2); diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs index eedc00a5613..4cb306b1950 100644 --- a/compiler/rustc_pattern_analysis/src/rustc.rs +++ b/compiler/rustc_pattern_analysis/src/rustc.rs @@ -462,6 +462,12 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { _ => bug!("pattern has unexpected type: pat: {:?}, ty: {:?}", pat, ty), }; } + PatKind::DerefPattern { .. } => { + // FIXME(deref_patterns): At least detect that `box _` is irrefutable. + fields = vec![]; + arity = 0; + ctor = Opaque(OpaqueId::new()); + } PatKind::Leaf { subpatterns } | PatKind::Variant { subpatterns, .. } => { match ty.kind() { ty::Tuple(fs) => { diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index 8b911a41a11..8b35087a005 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -674,6 +674,7 @@ symbols! { deref_method, deref_mut, deref_mut_method, + deref_patterns, deref_target, derive, derive_const, diff --git a/tests/ui/cfg/cfg-false-feature.stderr b/tests/ui/cfg/cfg-false-feature.stderr index 9309b59ca59..542aeaf5caf 100644 --- a/tests/ui/cfg/cfg-false-feature.stderr +++ b/tests/ui/cfg/cfg-false-feature.stderr @@ -1,15 +1,3 @@ -warning: trait aliases are experimental - --> $DIR/cfg-false-feature.rs:12:1 - | -LL | trait A = Clone; - | ^^^^^^^^^^^^^^^^ - | - = note: see issue #41517 for more information - = help: add `#![feature(trait_alias)]` to the crate attributes to enable - = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date - = warning: unstable syntax can change at any point in the future, causing a hard error! - = note: for more information, see issue #65860 - warning: box pattern syntax is experimental --> $DIR/cfg-false-feature.rs:16:9 | @@ -22,5 +10,17 @@ LL | let box _ = Box::new(0); = warning: unstable syntax can change at any point in the future, causing a hard error! = note: for more information, see issue #65860 +warning: trait aliases are experimental + --> $DIR/cfg-false-feature.rs:12:1 + | +LL | trait A = Clone; + | ^^^^^^^^^^^^^^^^ + | + = note: see issue #41517 for more information + = help: add `#![feature(trait_alias)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + = warning: unstable syntax can change at any point in the future, causing a hard error! + = note: for more information, see issue #65860 + warning: 2 warnings emitted diff --git a/tests/ui/feature-gates/feature-gate-deref_patterns.rs b/tests/ui/feature-gates/feature-gate-deref_patterns.rs new file mode 100644 index 00000000000..b43001f2d53 --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-deref_patterns.rs @@ -0,0 +1,9 @@ +fn main() { + // We reuse the `box` syntax so this doesn't actually test the feature gate but eh. + let box x = Box::new('c'); //~ ERROR box pattern syntax is experimental + println!("x: {}", x); + + // `box` syntax is allowed to be cfg-ed out for historical reasons (#65742). + #[cfg(FALSE)] + let box _x = Box::new('c'); +} diff --git a/tests/ui/feature-gates/feature-gate-deref_patterns.stderr b/tests/ui/feature-gates/feature-gate-deref_patterns.stderr new file mode 100644 index 00000000000..48426b50d89 --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-deref_patterns.stderr @@ -0,0 +1,13 @@ +error[E0658]: box pattern syntax is experimental + --> $DIR/feature-gate-deref_patterns.rs:3:9 + | +LL | let box x = Box::new('c'); + | ^^^^^ + | + = note: see issue #29641 for more information + = help: add `#![feature(box_patterns)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0658`. diff --git a/tests/ui/pattern/deref-patterns/typeck.rs b/tests/ui/pattern/deref-patterns/typeck.rs new file mode 100644 index 00000000000..20577abe485 --- /dev/null +++ b/tests/ui/pattern/deref-patterns/typeck.rs @@ -0,0 +1,31 @@ +//@ check-pass +#![feature(deref_patterns)] +#![allow(incomplete_features)] + +use std::rc::Rc; + +fn main() { + let vec: Vec = Vec::new(); + match vec { + box [..] => {} + _ => {} + } + match Box::new(true) { + box true => {} + _ => {} + } + match &Box::new(true) { + box true => {} + _ => {} + } + match &Rc::new(0) { + box (1..) => {} + _ => {} + } + // FIXME(deref_patterns): fails to typecheck because `"foo"` has type &str but deref creates a + // place of type `str`. + // match "foo".to_string() { + // box "foo" => {} + // _ => {} + // } +} -- cgit 1.4.1-3-g733a5