diff options
| -rw-r--r-- | compiler/rustc_middle/src/thir.rs | 65 |
1 files changed, 46 insertions, 19 deletions
diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs index 1300a06f375..9b63b3980d2 100644 --- a/compiler/rustc_middle/src/thir.rs +++ b/compiler/rustc_middle/src/thir.rs @@ -1073,8 +1073,33 @@ impl<'tcx> PatRangeBoundary<'tcx> { } } -impl<'tcx> fmt::Display for Pat<'tcx> { +impl<'tcx> Pat<'tcx> { + /// Prints a [`Pat`] to an owned string, for user-facing diagnostics. + /// + /// If we ever switch over to storing subpatterns as `PatId`, this will also + /// need to take a context that can resolve IDs to subpatterns. + pub fn to_string(&self) -> String { + format!("{}", self.display()) + } + + /// Used internally by [`fmt::Display`] for [`PatDisplay`]. + fn display(&self) -> PatDisplay<'_, 'tcx> { + PatDisplay { pat: self } + } +} + +/// Wrapper around [`&Pat<'tcx>`][`Pat`] that implements [`fmt::Display`]. +/// +/// If we ever switch over to storing subpatterns as `PatId`, this will also +/// need to hold a context that can resolve IDs to subpatterns. +struct PatDisplay<'pat, 'tcx> { + pat: &'pat Pat<'tcx>, +} + +impl<'pat, 'tcx> fmt::Display for PatDisplay<'pat, 'tcx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let &Self { pat } = self; + // Printing lists is a chore. let mut first = true; let mut start_or_continue = |s| { @@ -1087,20 +1112,22 @@ impl<'tcx> fmt::Display for Pat<'tcx> { }; let mut start_or_comma = || start_or_continue(", "); - match self.kind { + match pat.kind { PatKind::Wild => write!(f, "_"), PatKind::Never => write!(f, "!"), - PatKind::AscribeUserType { ref subpattern, .. } => write!(f, "{subpattern}: _"), + PatKind::AscribeUserType { ref subpattern, .. } => { + write!(f, "{}: _", subpattern.display()) + } PatKind::Binding { name, mode, ref subpattern, .. } => { f.write_str(mode.prefix_str())?; write!(f, "{name}")?; if let Some(ref subpattern) = *subpattern { - write!(f, " @ {subpattern}")?; + write!(f, " @ {}", subpattern.display())?; } Ok(()) } PatKind::Variant { ref subpatterns, .. } | PatKind::Leaf { ref subpatterns } => { - let variant_and_name = match self.kind { + let variant_and_name = match pat.kind { PatKind::Variant { adt_def, variant_index, .. } => ty::tls::with(|tcx| { let variant = adt_def.variant(variant_index); let adt_did = adt_def.did(); @@ -1113,7 +1140,7 @@ impl<'tcx> fmt::Display for Pat<'tcx> { }; Some((variant, name)) }), - _ => self.ty.ty_adt_def().and_then(|adt_def| { + _ => pat.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()))) @@ -1138,11 +1165,11 @@ impl<'tcx> fmt::Display for Pat<'tcx> { continue; } let name = variant.fields[p.field].name; - write!(f, "{}{}: {}", start_or_comma(), name, p.pattern)?; + write!(f, "{}{}: {}", start_or_comma(), name, p.pattern.display())?; printed += 1; } - let is_union = self.ty.ty_adt_def().is_some_and(|adt| adt.is_union()); + let is_union = pat.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())?; } @@ -1161,14 +1188,14 @@ impl<'tcx> fmt::Display for Pat<'tcx> { // 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)?; + write!(f, "{}", p.pattern.display())?; 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)?; + write!(f, "{}", p.pattern.display())?; } else { write!(f, "_")?; } @@ -1179,45 +1206,45 @@ impl<'tcx> fmt::Display for Pat<'tcx> { Ok(()) } PatKind::Deref { ref subpattern } => { - match self.ty.kind() { + match pat.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), + _ => bug!("{} is a bad Deref pattern type", pat.ty), } - write!(f, "{subpattern}") + write!(f, "{}", subpattern.display()) } PatKind::DerefPattern { ref subpattern, .. } => { - write!(f, "deref!({subpattern})") + write!(f, "deref!({})", subpattern.display()) } PatKind::Constant { value } => write!(f, "{value}"), PatKind::InlineConstant { def: _, ref subpattern } => { - write!(f, "{} (from inline const)", subpattern) + write!(f, "{} (from inline const)", subpattern.display()) } PatKind::Range(ref range) => write!(f, "{range}"), PatKind::Slice { ref prefix, ref slice, ref suffix } | PatKind::Array { ref prefix, ref slice, ref suffix } => { write!(f, "[")?; for p in prefix.iter() { - write!(f, "{}{}", start_or_comma(), p)?; + write!(f, "{}{}", start_or_comma(), p.display())?; } if let Some(ref slice) = *slice { write!(f, "{}", start_or_comma())?; match slice.kind { PatKind::Wild => {} - _ => write!(f, "{slice}")?, + _ => write!(f, "{}", slice.display())?, } write!(f, "..")?; } for p in suffix.iter() { - write!(f, "{}{}", start_or_comma(), p)?; + write!(f, "{}{}", start_or_comma(), p.display())?; } write!(f, "]") } PatKind::Or { ref pats } => { for pat in pats.iter() { - write!(f, "{}{}", start_or_continue(" | "), pat)?; + write!(f, "{}{}", start_or_continue(" | "), pat.display())?; } Ok(()) } |