From bdab21399372bee9127b5e6641c8a54034005138 Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Wed, 24 Jan 2024 20:04:33 +0100 Subject: [PATCH 1/2] Most of the `DeconstructedPat` `Debug` impl is reusable --- compiler/rustc_pattern_analysis/src/lib.rs | 8 +- compiler/rustc_pattern_analysis/src/pat.rs | 70 +++++++++++- compiler/rustc_pattern_analysis/src/rustc.rs | 110 ++----------------- 3 files changed, 86 insertions(+), 102 deletions(-) diff --git a/compiler/rustc_pattern_analysis/src/lib.rs b/compiler/rustc_pattern_analysis/src/lib.rs index 4fd01b5e638ce..5178490317804 100644 --- a/compiler/rustc_pattern_analysis/src/lib.rs +++ b/compiler/rustc_pattern_analysis/src/lib.rs @@ -108,8 +108,12 @@ pub trait TypeCx: Sized + fmt::Debug { /// This must follow the invariants of `ConstructorSet` fn ctors_for_ty(&self, ty: &Self::Ty) -> Result, Self::Error>; - /// Best-effort `Debug` implementation. - fn debug_pat(f: &mut fmt::Formatter<'_>, pat: &DeconstructedPat<'_, Self>) -> fmt::Result; + /// Write the name of the variant represented by `pat`. Used for the best-effort `Debug` impl of + /// `DeconstructedPat`. Only invoqued when `pat.ctor()` is `Struct | Variant(_) | UnionField`. + fn write_variant_name( + f: &mut fmt::Formatter<'_>, + pat: &crate::pat::DeconstructedPat<'_, Self>, + ) -> fmt::Result; /// Raise a bug. fn bug(&self, fmt: fmt::Arguments<'_>) -> !; diff --git a/compiler/rustc_pattern_analysis/src/pat.rs b/compiler/rustc_pattern_analysis/src/pat.rs index 8cd0ecb073c2f..e9f0a80699f8b 100644 --- a/compiler/rustc_pattern_analysis/src/pat.rs +++ b/compiler/rustc_pattern_analysis/src/pat.rs @@ -142,7 +142,75 @@ impl<'p, Cx: TypeCx> DeconstructedPat<'p, Cx> { /// This is best effort and not good enough for a `Display` impl. impl<'p, Cx: TypeCx> fmt::Debug for DeconstructedPat<'p, Cx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - Cx::debug_pat(f, self) + 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(", "); + + 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 pat.iter_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 => { + let subpattern = pat.iter_fields().next().unwrap(); + write!(f, "&{:?}", subpattern) + } + Slice(slice) => { + let mut subpatterns = pat.iter_fields(); + write!(f, "[")?; + match slice.kind { + SliceKind::FixedLen(_) => { + for p in subpatterns { + write!(f, "{}{:?}", start_or_comma(), p)?; + } + } + SliceKind::VarLen(prefix_len, _) => { + for p in subpatterns.by_ref().take(prefix_len) { + write!(f, "{}{:?}", start_or_comma(), p)?; + } + write!(f, "{}", start_or_comma())?; + write!(f, "..")?; + for p in subpatterns { + 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 pat.iter_fields() { + write!(f, "{}{:?}", start_or_continue(" | "), pat)?; + } + Ok(()) + } + Wildcard | Missing { .. } | NonExhaustive | Hidden => write!(f, "_ : {:?}", pat.ty()), + } } } diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs index d8c3c010a2a93..f60f1b9f96d4a 100644 --- a/compiler/rustc_pattern_analysis/src/rustc.rs +++ b/compiler/rustc_pattern_analysis/src/rustc.rs @@ -850,103 +850,6 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> { Pat { ty: pat.ty().inner(), span: DUMMY_SP, kind } } - - /// Best-effort `Debug` implementation. - pub(crate) fn debug_pat( - f: &mut fmt::Formatter<'_>, - pat: &crate::pat::DeconstructedPat<'_, Self>, - ) -> 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 pat.ctor() { - Struct | Variant(_) | UnionField => match pat.ty().kind() { - ty::Adt(def, _) if def.is_box() => { - // Without `box_patterns`, the only legal pattern of type `Box` is `_` (outside - // of `std`). So this branch is only reachable when the feature is enabled and - // the pattern is a box pattern. - let subpattern = pat.iter_fields().next().unwrap(); - write!(f, "box {subpattern:?}") - } - ty::Adt(..) | ty::Tuple(..) => { - let variant = - match pat.ty().kind() { - ty::Adt(adt, _) => Some(adt.variant( - RustcMatchCheckCtxt::variant_index_for_adt(pat.ctor(), *adt), - )), - ty::Tuple(_) => None, - _ => unreachable!(), - }; - - if let Some(variant) = variant { - write!(f, "{}", variant.name)?; - } - - // 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 pat.iter_fields() { - write!(f, "{}", start_or_comma())?; - write!(f, "{p:?}")?; - } - write!(f, ")") - } - _ => 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 => { - let subpattern = pat.iter_fields().next().unwrap(); - write!(f, "&{:?}", subpattern) - } - Slice(slice) => { - let mut subpatterns = pat.iter_fields(); - write!(f, "[")?; - match slice.kind { - SliceKind::FixedLen(_) => { - for p in subpatterns { - write!(f, "{}{:?}", start_or_comma(), p)?; - } - } - SliceKind::VarLen(prefix_len, _) => { - for p in subpatterns.by_ref().take(prefix_len) { - write!(f, "{}{:?}", start_or_comma(), p)?; - } - write!(f, "{}", start_or_comma())?; - write!(f, "..")?; - for p in subpatterns { - 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 pat.iter_fields() { - write!(f, "{}{:?}", start_or_continue(" | "), pat)?; - } - Ok(()) - } - Wildcard | Missing { .. } | NonExhaustive | Hidden => write!(f, "_ : {:?}", pat.ty()), - } - } } impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> { @@ -978,12 +881,21 @@ impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> { self.ctors_for_ty(*ty) } - fn debug_pat( + fn write_variant_name( f: &mut fmt::Formatter<'_>, pat: &crate::pat::DeconstructedPat<'_, Self>, ) -> fmt::Result { - Self::debug_pat(f, pat) + if let ty::Adt(adt, _) = pat.ty().kind() { + if adt.is_box() { + write!(f, "Box")? + } else { + let variant = adt.variant(Self::variant_index_for_adt(pat.ctor(), *adt)); + write!(f, "{}", variant.name)?; + } + } + Ok(()) } + fn bug(&self, fmt: fmt::Arguments<'_>) -> ! { span_bug!(self.scrut_span, "{}", fmt) } From 354b45f52854d4534aaf4bf860d539a9657a596f Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Wed, 24 Jan 2024 20:09:30 +0100 Subject: [PATCH 2/2] Improve `Range: Debug` impl --- .../rustc_pattern_analysis/src/constructor.rs | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/compiler/rustc_pattern_analysis/src/constructor.rs b/compiler/rustc_pattern_analysis/src/constructor.rs index eba71a23435a6..e94a0373c79ff 100644 --- a/compiler/rustc_pattern_analysis/src/constructor.rs +++ b/compiler/rustc_pattern_analysis/src/constructor.rs @@ -391,12 +391,18 @@ impl IntRange { /// first. impl fmt::Debug for IntRange { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - if let Finite(lo) = self.lo { + if self.is_singleton() { + // Only finite ranges can be singletons. + let Finite(lo) = self.lo else { unreachable!() }; write!(f, "{lo}")?; - } - write!(f, "{}", RangeEnd::Excluded)?; - if let Finite(hi) = self.hi { - write!(f, "{hi}")?; + } else { + if let Finite(lo) = self.lo { + write!(f, "{lo}")?; + } + write!(f, "{}", RangeEnd::Excluded)?; + if let Finite(hi) = self.hi { + write!(f, "{hi}")?; + } } Ok(()) }