Rollup merge of #146564 - cjgillot:mir-nolen, r=scottmcm

Remove Rvalue::Len again.

Now that we have `RawPtrKind::FakeForPtrMetadata`, we can reimplement `Rvalue::Len` using `PtrMetadata(&raw const (fake) place)`.

r? ``@scottmcm``

4 files changed, 0 insertions, 21 deletions

diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index f9d0a5f0a3b..96148fd5b92 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -1062,7 +1062,6 @@ impl<'tcx> Debug for Rvalue<'tcx> {
                 pretty_print_const(b, fmt, false)?;
                 write!(fmt, "]")
             }
-            Len(ref a) => write!(fmt, "Len({a:?})"),
             Cast(ref kind, ref place, ref ty) => {
                 with_no_trimmed_paths!(write!(fmt, "{place:?} as {ty} ({kind:?})"))
             }
diff --git a/compiler/rustc_middle/src/mir/statement.rs b/compiler/rustc_middle/src/mir/statement.rs
index ec2a8e86077..28294b47e90 100644
--- a/compiler/rustc_middle/src/mir/statement.rs
+++ b/compiler/rustc_middle/src/mir/statement.rs
@@ -697,7 +697,6 @@ impl<'tcx> Rvalue<'tcx> {
             | Rvalue::Ref(_, _, _)
             | Rvalue::ThreadLocalRef(_)
             | Rvalue::RawPtr(_, _)
-            | Rvalue::Len(_)
             | Rvalue::Cast(
                 CastKind::IntToInt
                 | CastKind::FloatToInt
@@ -739,7 +738,6 @@ impl<'tcx> Rvalue<'tcx> {
                 let place_ty = place.ty(local_decls, tcx).ty;
                 Ty::new_ptr(tcx, place_ty, kind.to_mutbl_lossy())
             }
-            Rvalue::Len(..) => tcx.types.usize,
             Rvalue::Cast(.., ty) => ty,
             Rvalue::BinaryOp(op, box (ref lhs, ref rhs)) => {
                 let lhs_ty = lhs.ty(local_decls, tcx);
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index d402ea4b04f..e6c8512564e 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -1407,16 +1407,6 @@ pub enum Rvalue<'tcx> {
     /// model.
     RawPtr(RawPtrKind, Place<'tcx>),
 
-    /// Yields the length of the place, as a `usize`.
-    ///
-    /// If the type of the place is an array, this is the array length. For slices (`[T]`, not
-    /// `&[T]`) this accesses the place's metadata to determine the length. This rvalue is
-    /// ill-formed for places of other types.
-    ///
-    /// This cannot be a `UnOp(PtrMetadata, _)` because that expects a value, and we only
-    /// have a place, and `UnOp(PtrMetadata, RawPtr(place))` is not a thing.
-    Len(Place<'tcx>),
-
     /// Performs essentially all of the casts that can be performed via `as`.
     ///
     /// This allows for casts from/to a variety of types.
diff --git a/compiler/rustc_middle/src/mir/visit.rs b/compiler/rustc_middle/src/mir/visit.rs
index b498b7b8912..07a15b3cd18 100644
--- a/compiler/rustc_middle/src/mir/visit.rs
+++ b/compiler/rustc_middle/src/mir/visit.rs
@@ -717,14 +717,6 @@ macro_rules! make_mir_visitor {
                         self.visit_place(path, ctx, location);
                     }
 
-                    Rvalue::Len(path) => {
-                        self.visit_place(
-                            path,
-                            PlaceContext::NonMutatingUse(NonMutatingUseContext::Inspect),
-                            location
-                        );
-                    }
-
                     Rvalue::Cast(_cast_kind, operand, ty) => {
                         self.visit_operand(operand, location);
                         self.visit_ty($(& $mutability)? *ty, TyContext::Location(location));