diff options
Diffstat (limited to 'compiler/rustc_pattern_analysis/src')
| -rw-r--r-- | compiler/rustc_pattern_analysis/src/rustc.rs | 26 | ||||
| -rw-r--r-- | compiler/rustc_pattern_analysis/src/rustc/print.rs | 193 |
2 files changed, 208 insertions, 11 deletions
diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs index 13501720858..6290aeb2523 100644 --- a/compiler/rustc_pattern_analysis/src/rustc.rs +++ b/compiler/rustc_pattern_analysis/src/rustc.rs @@ -7,7 +7,7 @@ use rustc_hir::HirId; use rustc_index::{Idx, IndexVec}; use rustc_middle::middle::stability::EvalResult; use rustc_middle::mir::{self, Const}; -use rustc_middle::thir::{self, FieldPat, Pat, PatKind, PatRange, PatRangeBoundary}; +use rustc_middle::thir::{self, Pat, PatKind, PatRange, PatRangeBoundary}; use rustc_middle::ty::layout::IntegerExt; use rustc_middle::ty::{ self, FieldDef, OpaqueTypeKey, ScalarInt, Ty, TyCtxt, TypeVisitableExt, VariantDef, @@ -26,6 +26,8 @@ use crate::pat_column::PatternColumn; use crate::usefulness::{compute_match_usefulness, PlaceValidity}; use crate::{errors, Captures, PatCx, PrivateUninhabitedField}; +mod print; + // Re-export rustc-specific versions of all these types. pub type Constructor<'p, 'tcx> = crate::constructor::Constructor<RustcPatCtxt<'p, 'tcx>>; pub type ConstructorSet<'p, 'tcx> = crate::constructor::ConstructorSet<RustcPatCtxt<'p, 'tcx>>; @@ -773,8 +775,9 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { } } - /// Convert back to a `thir::Pat` for diagnostic purposes. - fn hoist_pat_range(&self, range: &IntRange, ty: RevealedTy<'tcx>) -> Pat<'tcx> { + /// Convert to a [`print::Pat`] for diagnostic purposes. + fn hoist_pat_range(&self, range: &IntRange, ty: RevealedTy<'tcx>) -> print::Pat<'tcx> { + use print::{Pat, PatKind}; use MaybeInfiniteInt::*; let cx = self; let kind = if matches!((range.lo, range.hi), (NegInfinity, PosInfinity)) { @@ -808,19 +811,20 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { PatKind::Range(Box::new(PatRange { lo, hi, end, ty: ty.inner() })) }; - Pat { ty: ty.inner(), span: DUMMY_SP, kind } + Pat { ty: ty.inner(), kind } } /// Prints a [`WitnessPat`] to an owned string, for diagnostic purposes. pub fn print_witness_pat(&self, pat: &WitnessPat<'p, 'tcx>) -> String { - // This works by converting the witness pattern back to a `thir::Pat` + // This works by converting the witness pattern to a `print::Pat` // and then printing that, but callers don't need to know that. self.hoist_witness_pat(pat).to_string() } - /// Convert back to a `thir::Pat` for diagnostic purposes. This panics for patterns that don't + /// Convert to a [`print::Pat`] for diagnostic purposes. This panics for patterns that don't /// appear in diagnostics, like float ranges. - fn hoist_witness_pat(&self, pat: &WitnessPat<'p, 'tcx>) -> Pat<'tcx> { + fn hoist_witness_pat(&self, pat: &WitnessPat<'p, 'tcx>) -> print::Pat<'tcx> { + use print::{FieldPat, Pat, PatKind}; let cx = self; let is_wildcard = |pat: &Pat<'_>| matches!(pat.kind, PatKind::Wild); let mut subpatterns = pat.iter_fields().map(|p| Box::new(cx.hoist_witness_pat(p))); @@ -840,7 +844,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { // the pattern is a box pattern. PatKind::Deref { subpattern: subpatterns.next().unwrap() } } - ty::Adt(adt_def, args) => { + ty::Adt(adt_def, _args) => { let variant_index = RustcPatCtxt::variant_index_for_adt(&pat.ctor(), *adt_def); let subpatterns = subpatterns .enumerate() @@ -848,7 +852,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { .collect(); if adt_def.is_enum() { - PatKind::Variant { adt_def: *adt_def, args, variant_index, subpatterns } + PatKind::Variant { adt_def: *adt_def, variant_index, subpatterns } } else { PatKind::Leaf { subpatterns } } @@ -885,7 +889,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { } } let suffix: Box<[_]> = subpatterns.collect(); - let wild = Pat::wildcard_from_ty(pat.ty().inner()); + let wild = Pat { ty: pat.ty().inner(), kind: PatKind::Wild }; PatKind::Slice { prefix: prefix.into_boxed_slice(), slice: Some(Box::new(wild)), @@ -906,7 +910,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> { } }; - Pat { ty: pat.ty().inner(), span: DUMMY_SP, kind } + Pat { ty: pat.ty().inner(), kind } } } diff --git a/compiler/rustc_pattern_analysis/src/rustc/print.rs b/compiler/rustc_pattern_analysis/src/rustc/print.rs new file mode 100644 index 00000000000..4b76764e8b1 --- /dev/null +++ b/compiler/rustc_pattern_analysis/src/rustc/print.rs @@ -0,0 +1,193 @@ +//! Pattern analysis sometimes wants to print patterns as part of a user-visible +//! diagnostic. +//! +//! Historically it did so by creating a synthetic [`thir::Pat`](rustc_middle::thir::Pat) +//! and printing that, but doing so was making it hard to modify the THIR pattern +//! representation for other purposes. +//! +//! So this module contains a forked copy of `thir::Pat` that is used _only_ +//! for diagnostics, and has been partly simplified to remove things that aren't +//! needed for printing. + +use std::fmt; + +use rustc_middle::thir::PatRange; +use rustc_middle::ty::{self, AdtDef, Ty}; +use rustc_middle::{bug, mir}; +use rustc_span::sym; +use rustc_target::abi::{FieldIdx, VariantIdx}; + +#[derive(Clone, Debug)] +pub(crate) struct FieldPat<'tcx> { + pub(crate) field: FieldIdx, + pub(crate) pattern: Box<Pat<'tcx>>, +} + +#[derive(Clone, Debug)] +pub(crate) struct Pat<'tcx> { + pub(crate) ty: Ty<'tcx>, + pub(crate) kind: PatKind<'tcx>, +} + +#[derive(Clone, Debug)] +pub(crate) enum PatKind<'tcx> { + Wild, + + Variant { + adt_def: AdtDef<'tcx>, + variant_index: VariantIdx, + subpatterns: Vec<FieldPat<'tcx>>, + }, + + Leaf { + subpatterns: Vec<FieldPat<'tcx>>, + }, + + Deref { + subpattern: Box<Pat<'tcx>>, + }, + + Constant { + value: mir::Const<'tcx>, + }, + + Range(Box<PatRange<'tcx>>), + + Slice { + prefix: Box<[Box<Pat<'tcx>>]>, + slice: Option<Box<Pat<'tcx>>>, + suffix: Box<[Box<Pat<'tcx>>]>, + }, + + Never, +} + +impl<'tcx> fmt::Display for Pat<'tcx> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + // Printing lists is a chore. + 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.kind { + PatKind::Wild => write!(f, "_"), + PatKind::Never => write!(f, "!"), + PatKind::Variant { ref subpatterns, .. } | PatKind::Leaf { ref subpatterns } => { + let variant_and_name = match self.kind { + PatKind::Variant { adt_def, variant_index, .. } => ty::tls::with(|tcx| { + let variant = adt_def.variant(variant_index); + let adt_did = adt_def.did(); + let name = if tcx.get_diagnostic_item(sym::Option) == Some(adt_did) + || tcx.get_diagnostic_item(sym::Result) == Some(adt_did) + { + variant.name.to_string() + } else { + format!("{}::{}", tcx.def_path_str(adt_def.did()), variant.name) + }; + Some((variant, name)) + }), + _ => self.ty.ty_adt_def().and_then(|adt_def| { + if !adt_def.is_enum() { + ty::tls::with(|tcx| { + Some((adt_def.non_enum_variant(), tcx.def_path_str(adt_def.did()))) + }) + } else { + None + } + }), + }; + + if let Some((variant, name)) = &variant_and_name { + write!(f, "{name}")?; + + // Only for Adt we can have `S {...}`, + // which we handle separately here. + if variant.ctor.is_none() { + write!(f, " {{ ")?; + + let mut printed = 0; + for p in subpatterns { + if let PatKind::Wild = p.pattern.kind { + continue; + } + let name = variant.fields[p.field].name; + write!(f, "{}{}: {}", start_or_comma(), name, p.pattern)?; + printed += 1; + } + + let is_union = self.ty.ty_adt_def().is_some_and(|adt| adt.is_union()); + if printed < variant.fields.len() && (!is_union || printed == 0) { + write!(f, "{}..", start_or_comma())?; + } + + return write!(f, " }}"); + } + } + + let num_fields = + variant_and_name.as_ref().map_or(subpatterns.len(), |(v, _)| v.fields.len()); + if num_fields != 0 || variant_and_name.is_none() { + write!(f, "(")?; + for i in 0..num_fields { + write!(f, "{}", start_or_comma())?; + + // Common case: the field is where we expect it. + if let Some(p) = subpatterns.get(i) { + if p.field.index() == i { + write!(f, "{}", p.pattern)?; + continue; + } + } + + // Otherwise, we have to go looking for it. + if let Some(p) = subpatterns.iter().find(|p| p.field.index() == i) { + write!(f, "{}", p.pattern)?; + } else { + write!(f, "_")?; + } + } + write!(f, ")")?; + } + + Ok(()) + } + PatKind::Deref { ref subpattern } => { + match self.ty.kind() { + ty::Adt(def, _) if def.is_box() => write!(f, "box ")?, + ty::Ref(_, _, mutbl) => { + write!(f, "&{}", mutbl.prefix_str())?; + } + _ => bug!("{} is a bad Deref pattern type", self.ty), + } + write!(f, "{subpattern}") + } + PatKind::Constant { value } => write!(f, "{value}"), + PatKind::Range(ref range) => write!(f, "{range}"), + PatKind::Slice { ref prefix, ref slice, ref suffix } => { + write!(f, "[")?; + for p in prefix.iter() { + write!(f, "{}{}", start_or_comma(), p)?; + } + if let Some(ref slice) = *slice { + write!(f, "{}", start_or_comma())?; + match slice.kind { + PatKind::Wild => {} + _ => write!(f, "{slice}")?, + } + write!(f, "..")?; + } + for p in suffix.iter() { + write!(f, "{}{}", start_or_comma(), p)?; + } + write!(f, "]") + } + } + } +} |