diff options
Diffstat (limited to 'compiler/rustc_mir_build/src/thir/pattern/mod.rs')
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/pattern/mod.rs | 147 |
1 files changed, 75 insertions, 72 deletions
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs index d8850b10433..73d60cf4442 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs @@ -13,14 +13,15 @@ use rustc_hir::def::{CtorOf, DefKind, Res}; use rustc_hir::pat_util::EnumerateAndAdjustIterator; use rustc_hir::{self as hir, LangItem, RangeEnd}; use rustc_index::Idx; +use rustc_infer::infer::TyCtxtInferExt; use rustc_middle::mir::interpret::LitToConstInput; use rustc_middle::thir::{ Ascription, FieldPat, LocalVarId, Pat, PatKind, PatRange, PatRangeBoundary, }; use rustc_middle::ty::layout::IntegerExt; -use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, Ty, TyCtxt, TypeVisitableExt}; +use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, Ty, TyCtxt, TypingMode}; use rustc_middle::{bug, span_bug}; -use rustc_span::def_id::LocalDefId; +use rustc_span::def_id::DefId; use rustc_span::{ErrorGuaranteed, Span}; use tracing::{debug, instrument}; @@ -124,7 +125,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { expr: Option<&'tcx hir::PatExpr<'tcx>>, // Out-parameters collecting extra data to be reapplied by the caller ascriptions: &mut Vec<Ascription<'tcx>>, - inline_consts: &mut Vec<LocalDefId>, + expanded_consts: &mut Vec<DefId>, ) -> Result<Option<PatRangeBoundary<'tcx>>, ErrorGuaranteed> { let Some(expr) = expr else { return Ok(None) }; @@ -139,10 +140,8 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { ascriptions.push(ascription); kind = subpattern.kind; } - PatKind::ExpandedConstant { is_inline, def_id, subpattern } => { - if is_inline { - inline_consts.extend(def_id.as_local()); - } + PatKind::ExpandedConstant { def_id, subpattern } => { + expanded_consts.push(def_id); kind = subpattern.kind; } _ => break, @@ -221,10 +220,10 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { // Collect extra data while lowering the endpoints, to be reapplied later. let mut ascriptions = vec![]; - let mut inline_consts = vec![]; + let mut expanded_consts = vec![]; let mut lower_endpoint = - |expr| self.lower_pattern_range_endpoint(expr, &mut ascriptions, &mut inline_consts); + |expr| self.lower_pattern_range_endpoint(expr, &mut ascriptions, &mut expanded_consts); let lo = lower_endpoint(lo_expr)?.unwrap_or(PatRangeBoundary::NegInfinity); let hi = lower_endpoint(hi_expr)?.unwrap_or(PatRangeBoundary::PosInfinity); @@ -269,17 +268,12 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { // `Foo::<'a>::A..=Foo::B`), we need to put the ascriptions for the associated // constants somewhere. Have them on the range pattern. for ascription in ascriptions { - kind = PatKind::AscribeUserType { - ascription, - subpattern: Box::new(Pat { span, ty, kind }), - }; + let subpattern = Box::new(Pat { span, ty, kind }); + kind = PatKind::AscribeUserType { ascription, subpattern }; } - for def in inline_consts { - kind = PatKind::ExpandedConstant { - def_id: def.to_def_id(), - is_inline: true, - subpattern: Box::new(Pat { span, ty, kind }), - }; + for def_id in expanded_consts { + let subpattern = Box::new(Pat { span, ty, kind }); + kind = PatKind::ExpandedConstant { def_id, subpattern }; } Ok(kind) } @@ -569,15 +563,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { // Lower the named constant to a THIR pattern. let args = self.typeck_results.node_args(id); let c = ty::Const::new_unevaluated(self.tcx, ty::UnevaluatedConst { def: def_id, args }); - let subpattern = self.const_to_pat(c, ty, id, span); - - // Wrap the pattern in a marker node to indicate that it is the result - // of lowering a named constant. This marker is used for improved - // diagnostics in some situations, but has no effect at runtime. - let mut pattern = { - let kind = PatKind::ExpandedConstant { subpattern, def_id, is_inline: false }; - Box::new(Pat { span, ty, kind }) - }; + let mut pattern = self.const_to_pat(c, ty, id, span); // If this is an associated constant with an explicit user-written // type, add an ascription node (e.g. `<Foo<'a> as MyTrait>::CONST`). @@ -614,18 +600,37 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { let ty = tcx.typeck(def_id).node_type(block.hir_id); let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id()); - let parent_args = - tcx.erase_regions(ty::GenericArgs::identity_for_item(tcx, typeck_root_def_id)); + let parent_args = ty::GenericArgs::identity_for_item(tcx, typeck_root_def_id); let args = ty::InlineConstArgs::new(tcx, ty::InlineConstArgsParts { parent_args, ty }).args; - debug_assert!(!args.has_free_regions()); - let ct = ty::UnevaluatedConst { def: def_id.to_def_id(), args }; - let subpattern = self.const_to_pat(ty::Const::new_unevaluated(self.tcx, ct), ty, id, span); - - // Wrap the pattern in a marker node to indicate that it is the result - // of lowering an inline const block. - PatKind::ExpandedConstant { subpattern, def_id: def_id.to_def_id(), is_inline: true } + let c = ty::Const::new_unevaluated(self.tcx, ct); + let pattern = self.const_to_pat(c, ty, id, span); + + // Apply a type ascription for the inline constant. + let annotation = { + let infcx = tcx.infer_ctxt().build(TypingMode::non_body_analysis()); + let args = ty::InlineConstArgs::new( + tcx, + ty::InlineConstArgsParts { parent_args, ty: infcx.next_ty_var(span) }, + ) + .args; + infcx.canonicalize_user_type_annotation(ty::UserType::new(ty::UserTypeKind::TypeOf( + def_id.to_def_id(), + ty::UserArgs { args, user_self_ty: None }, + ))) + }; + let annotation = + CanonicalUserTypeAnnotation { user_ty: Box::new(annotation), span, inferred_ty: ty }; + PatKind::AscribeUserType { + subpattern: pattern, + ascription: Ascription { + annotation, + // Note that we use `Contravariant` here. See the `variance` field documentation + // for details. + variance: ty::Contravariant, + }, + } } /// Lowers the kinds of "expression" that can appear in a HIR pattern: @@ -637,43 +642,41 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { expr: &'tcx hir::PatExpr<'tcx>, pat_ty: Option<Ty<'tcx>>, ) -> PatKind<'tcx> { - let (lit, neg) = match &expr.kind { - hir::PatExprKind::Path(qpath) => { - return self.lower_path(qpath, expr.hir_id, expr.span).kind; - } + match &expr.kind { + hir::PatExprKind::Path(qpath) => self.lower_path(qpath, expr.hir_id, expr.span).kind, hir::PatExprKind::ConstBlock(anon_const) => { - return self.lower_inline_const(anon_const, expr.hir_id, expr.span); + self.lower_inline_const(anon_const, expr.hir_id, expr.span) } - hir::PatExprKind::Lit { lit, negated } => (lit, *negated), - }; - - // We handle byte string literal patterns by using the pattern's type instead of the - // literal's type in `const_to_pat`: if the literal `b"..."` matches on a slice reference, - // the pattern's type will be `&[u8]` whereas the literal's type is `&[u8; 3]`; using the - // pattern's type means we'll properly translate it to a slice reference pattern. This works - // because slices and arrays have the same valtree representation. - // HACK: As an exception, use the literal's type if `pat_ty` is `String`; this can happen if - // `string_deref_patterns` is enabled. There's a special case for that when lowering to MIR. - // FIXME(deref_patterns): This hack won't be necessary once `string_deref_patterns` is - // superseded by a more general implementation of deref patterns. - let ct_ty = match pat_ty { - Some(pat_ty) - if let ty::Adt(def, _) = *pat_ty.kind() - && self.tcx.is_lang_item(def.did(), LangItem::String) => - { - if !self.tcx.features().string_deref_patterns() { - span_bug!( - expr.span, - "matching on `String` went through without enabling string_deref_patterns" - ); - } - self.typeck_results.node_type(expr.hir_id) + hir::PatExprKind::Lit { lit, negated } => { + // We handle byte string literal patterns by using the pattern's type instead of the + // literal's type in `const_to_pat`: if the literal `b"..."` matches on a slice reference, + // the pattern's type will be `&[u8]` whereas the literal's type is `&[u8; 3]`; using the + // pattern's type means we'll properly translate it to a slice reference pattern. This works + // because slices and arrays have the same valtree representation. + // HACK: As an exception, use the literal's type if `pat_ty` is `String`; this can happen if + // `string_deref_patterns` is enabled. There's a special case for that when lowering to MIR. + // FIXME(deref_patterns): This hack won't be necessary once `string_deref_patterns` is + // superseded by a more general implementation of deref patterns. + let ct_ty = match pat_ty { + Some(pat_ty) + if let ty::Adt(def, _) = *pat_ty.kind() + && self.tcx.is_lang_item(def.did(), LangItem::String) => + { + if !self.tcx.features().string_deref_patterns() { + span_bug!( + expr.span, + "matching on `String` went through without enabling string_deref_patterns" + ); + } + self.typeck_results.node_type(expr.hir_id) + } + Some(pat_ty) => pat_ty, + None => self.typeck_results.node_type(expr.hir_id), + }; + let lit_input = LitToConstInput { lit: &lit.node, ty: ct_ty, neg: *negated }; + let constant = self.tcx.at(expr.span).lit_to_const(lit_input); + self.const_to_pat(constant, ct_ty, expr.hir_id, lit.span).kind } - Some(pat_ty) => pat_ty, - None => self.typeck_results.node_type(expr.hir_id), - }; - let lit_input = LitToConstInput { lit: &lit.node, ty: ct_ty, neg }; - let constant = self.tcx.at(expr.span).lit_to_const(lit_input); - self.const_to_pat(constant, ct_ty, expr.hir_id, lit.span).kind + } } } |