From e4487ad391503fa109506c40aeba377fda0d97dd Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Tue, 5 Mar 2024 00:16:11 +0100 Subject: [PATCH] Improve the `WitnessPat: Debug` impl --- .../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(-) 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)?; } }