Rollup merge of #106583 - estebank:suggest-result-coercion, r=compiler-errors

[rust.git] / compiler / rustc_middle / src / ty / sty.rs

diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 14e5f01099a0832b94fa095941dc837402babc4d..6a7b23e40a7792edb3cb7f72000cbb2f6a7321f3 100644 (file)
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -7,8 +7,8 @@
 use crate::ty::visit::ValidateBoundVars;
 use crate::ty::InferTy::*;
 use crate::ty::{
-    self, AdtDef, DefIdTree, Discr, Term, Ty, TyCtxt, TypeFlags, TypeSuperVisitable, TypeVisitable,
-    TypeVisitor,
+    self, AdtDef, DefIdTree, Discr, FallibleTypeFolder, Term, Ty, TyCtxt, TypeFlags, TypeFoldable,
+    TypeSuperFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitor,
 };
 use crate::ty::{List, ParamEnv};
 use hir::def::DefKind;
@@ -100,6 +100,13 @@ pub fn get_name(&self) -> Option<Symbol> {
 
         None
     }
+
+    pub fn get_id(&self) -> Option<DefId> {
+        match *self {
+            BoundRegionKind::BrNamed(id, _) => return Some(id),
+            _ => None,
+        }
+    }
 }
 
 pub trait Article {
@@ -1135,12 +1142,87 @@ pub fn iter(self) -> impl Iterator<Item = ty::Binder<'tcx, T::Item>> {
     }
 }
 
+struct SkipBindersAt<'tcx> {
+    tcx: TyCtxt<'tcx>,
+    index: ty::DebruijnIndex,
+}
+
+impl<'tcx> FallibleTypeFolder<'tcx> for SkipBindersAt<'tcx> {
+    type Error = ();
+
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
+    fn try_fold_binder<T>(&mut self, t: Binder<'tcx, T>) -> Result<Binder<'tcx, T>, Self::Error>
+    where
+        T: ty::TypeFoldable<'tcx>,
+    {
+        self.index.shift_in(1);
+        let value = t.try_map_bound(|t| t.try_fold_with(self));
+        self.index.shift_out(1);
+        value
+    }
+
+    fn try_fold_ty(&mut self, ty: Ty<'tcx>) -> Result<Ty<'tcx>, Self::Error> {
+        if !ty.has_escaping_bound_vars() {
+            Ok(ty)
+        } else if let ty::Bound(index, bv) = *ty.kind() {
+            if index == self.index {
+                Err(())
+            } else {
+                Ok(self.tcx().mk_ty(ty::Bound(index.shifted_out(1), bv)))
+            }
+        } else {
+            ty.try_super_fold_with(self)
+        }
+    }
+
+    fn try_fold_region(&mut self, r: ty::Region<'tcx>) -> Result<ty::Region<'tcx>, Self::Error> {
+        if !r.has_escaping_bound_vars() {
+            Ok(r)
+        } else if let ty::ReLateBound(index, bv) = r.kind() {
+            if index == self.index {
+                Err(())
+            } else {
+                Ok(self.tcx().mk_region(ty::ReLateBound(index.shifted_out(1), bv)))
+            }
+        } else {
+            r.try_super_fold_with(self)
+        }
+    }
+
+    fn try_fold_const(&mut self, ct: ty::Const<'tcx>) -> Result<ty::Const<'tcx>, Self::Error> {
+        if !ct.has_escaping_bound_vars() {
+            Ok(ct)
+        } else if let ty::ConstKind::Bound(index, bv) = ct.kind() {
+            if index == self.index {
+                Err(())
+            } else {
+                Ok(self.tcx().mk_const(
+                    ty::ConstKind::Bound(index.shifted_out(1), bv),
+                    ct.ty().try_fold_with(self)?,
+                ))
+            }
+        } else {
+            ct.try_super_fold_with(self)
+        }
+    }
+
+    fn try_fold_predicate(
+        &mut self,
+        p: ty::Predicate<'tcx>,
+    ) -> Result<ty::Predicate<'tcx>, Self::Error> {
+        if !p.has_escaping_bound_vars() { Ok(p) } else { p.try_super_fold_with(self) }
+    }
+}
+
 /// Represents the projection of an associated type.
 ///
 /// For a projection, this would be `<Ty as Trait<...>>::N`.
 ///
 /// For an opaque type, there is no explicit syntax.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct AliasTy<'tcx> {
     /// The parameters of the associated or opaque item.
@@ -1163,11 +1245,26 @@ pub struct AliasTy<'tcx> {
     /// aka. `tcx.parent(def_id)`.
     pub def_id: DefId,
 
-    /// This field exists to prevent the creation of `ProjectionTy` without using
+    /// This field exists to prevent the creation of `AliasTy` without using
     /// [TyCtxt::mk_alias_ty].
     pub(super) _use_mk_alias_ty_instead: (),
 }
 
+impl<'tcx> AliasTy<'tcx> {
+    pub fn kind(self, tcx: TyCtxt<'tcx>) -> ty::AliasKind {
+        match tcx.def_kind(self.def_id) {
+            DefKind::AssocTy | DefKind::ImplTraitPlaceholder => ty::Projection,
+            DefKind::OpaqueTy => ty::Opaque,
+            kind => bug!("unexpected DefKind in AliasTy: {kind:?}"),
+        }
+    }
+
+    pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
+        tcx.mk_ty(ty::Alias(self.kind(tcx), self))
+    }
+}
+
+/// The following methods work only with associated type projections.
 impl<'tcx> AliasTy<'tcx> {
     pub fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId {
         match tcx.def_kind(self.def_id) {
@@ -1175,7 +1272,7 @@ pub fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId {
             DefKind::ImplTraitPlaceholder => {
                 tcx.parent(tcx.impl_trait_in_trait_parent(self.def_id))
             }
-            kind => bug!("unexpected DefKind in ProjectionTy: {kind:?}"),
+            kind => bug!("expected a projection AliasTy; found {kind:?}"),
         }
     }
 
@@ -1686,7 +1783,7 @@ pub fn ty_vid(self) -> Option<ty::TyVid> {
     }
 
     #[inline]
-    pub fn is_ty_infer(self) -> bool {
+    pub fn is_ty_or_numeric_infer(self) -> bool {
         matches!(self.kind(), Infer(_))
     }
 
@@ -1929,7 +2026,7 @@ impl<'tcx> TypeVisitor<'tcx> for ContainsTyVisitor<'tcx> {
             type BreakTy = ();
 
             fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-                if self.0 == t { ControlFlow::BREAK } else { t.super_visit_with(self) }
+                if self.0 == t { ControlFlow::Break(()) } else { t.super_visit_with(self) }
             }
         }