Merging upstream version 1.66.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

17 files changed, 414 insertions, 199 deletions

diff --git a/compiler/rustc_mir_transform/Cargo.toml b/compiler/rustc_mir_transform/Cargo.toml
index 85b7a4af5..53545cff0 100644
--- a/compiler/rustc_mir_transform/Cargo.toml
+++ b/compiler/rustc_mir_transform/Cargo.toml
@@ -4,7 +4,6 @@ version = "0.0.0"
 edition = "2021"
 
 [lib]
-doctest = false
 
 [dependencies]
 itertools = "0.10.1"
diff --git a/compiler/rustc_mir_transform/src/check_const_item_mutation.rs b/compiler/rustc_mir_transform/src/check_const_item_mutation.rs
index 8838b14c5..fa5f392fa 100644
--- a/compiler/rustc_mir_transform/src/check_const_item_mutation.rs
+++ b/compiler/rustc_mir_transform/src/check_const_item_mutation.rs
@@ -1,4 +1,4 @@
-use rustc_errors::{DiagnosticBuilder, LintDiagnosticBuilder};
+use rustc_errors::{DiagnosticBuilder, DiagnosticMessage};
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
@@ -63,7 +63,10 @@ impl<'tcx> ConstMutationChecker<'_, 'tcx> {
         place: &Place<'tcx>,
         const_item: DefId,
         location: Location,
-        decorate: impl for<'b> FnOnce(LintDiagnosticBuilder<'b, ()>) -> DiagnosticBuilder<'b, ()>,
+        msg: impl Into<DiagnosticMessage>,
+        decorate: impl for<'a, 'b> FnOnce(
+            &'a mut DiagnosticBuilder<'b, ()>,
+        ) -> &'a mut DiagnosticBuilder<'b, ()>,
     ) {
         // Don't lint on borrowing/assigning when a dereference is involved.
         // If we 'leave' the temporary via a dereference, we must
@@ -84,10 +87,10 @@ impl<'tcx> ConstMutationChecker<'_, 'tcx> {
                 CONST_ITEM_MUTATION,
                 lint_root,
                 source_info.span,
+                msg,
                 |lint| {
                     decorate(lint)
                         .span_note(self.tcx.def_span(const_item), "`const` item defined here")
-                        .emit();
                 },
             );
         }
@@ -102,10 +105,8 @@ impl<'tcx> Visitor<'tcx> for ConstMutationChecker<'_, 'tcx> {
             // so emitting a lint would be redundant.
             if !lhs.projection.is_empty() {
                 if let Some(def_id) = self.is_const_item_without_destructor(lhs.local) {
-                    self.lint_const_item_usage(&lhs, def_id, loc, |lint| {
-                        let mut lint = lint.build("attempting to modify a `const` item");
-                        lint.note("each usage of a `const` item creates a new temporary; the original `const` item will not be modified");
-                        lint
+                    self.lint_const_item_usage(&lhs, def_id, loc, "attempting to modify a `const` item",|lint| {
+                        lint.note("each usage of a `const` item creates a new temporary; the original `const` item will not be modified")
                     })
                 }
             }
@@ -137,8 +138,7 @@ impl<'tcx> Visitor<'tcx> for ConstMutationChecker<'_, 'tcx> {
                 });
                 let lint_loc =
                     if method_did.is_some() { self.body.terminator_loc(loc.block) } else { loc };
-                self.lint_const_item_usage(place, def_id, lint_loc, |lint| {
-                    let mut lint = lint.build("taking a mutable reference to a `const` item");
+                self.lint_const_item_usage(place, def_id, lint_loc, "taking a mutable reference to a `const` item", |lint| {
                     lint
                         .note("each usage of a `const` item creates a new temporary")
                         .note("the mutable reference will refer to this temporary, not the original `const` item");
diff --git a/compiler/rustc_mir_transform/src/check_packed_ref.rs b/compiler/rustc_mir_transform/src/check_packed_ref.rs
index 3b7ba3f9a..51abcf511 100644
--- a/compiler/rustc_mir_transform/src/check_packed_ref.rs
+++ b/compiler/rustc_mir_transform/src/check_packed_ref.rs
@@ -33,21 +33,27 @@ struct PackedRefChecker<'a, 'tcx> {
 fn unsafe_derive_on_repr_packed(tcx: TyCtxt<'_>, def_id: LocalDefId) {
     let lint_hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
 
-    tcx.struct_span_lint_hir(UNALIGNED_REFERENCES, lint_hir_id, tcx.def_span(def_id), |lint| {
-        // FIXME: when we make this a hard error, this should have its
-        // own error code.
-        let extra = if tcx.generics_of(def_id).own_requires_monomorphization() {
-            "with type or const parameters"
-        } else {
-            "that does not derive `Copy`"
-        };
-        let message = format!(
-            "`{}` can't be derived on this `#[repr(packed)]` struct {}",
-            tcx.item_name(tcx.trait_id_of_impl(def_id.to_def_id()).expect("derived trait name")),
-            extra
-        );
-        lint.build(message).emit();
-    });
+    // FIXME: when we make this a hard error, this should have its
+    // own error code.
+
+    let extra = if tcx.generics_of(def_id).own_requires_monomorphization() {
+        "with type or const parameters"
+    } else {
+        "that does not derive `Copy`"
+    };
+    let message = format!(
+        "`{}` can't be derived on this `#[repr(packed)]` struct {}",
+        tcx.item_name(tcx.trait_id_of_impl(def_id.to_def_id()).expect("derived trait name")),
+        extra
+    );
+
+    tcx.struct_span_lint_hir(
+        UNALIGNED_REFERENCES,
+        lint_hir_id,
+        tcx.def_span(def_id),
+        message,
+        |lint| lint,
+    );
 }
 
 impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> {
@@ -86,8 +92,9 @@ impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> {
                         UNALIGNED_REFERENCES,
                         lint_root,
                         source_info.span,
+                        "reference to packed field is unaligned",
                         |lint| {
-                            lint.build("reference to packed field is unaligned")
+                            lint
                                 .note(
                                     "fields of packed structs are not properly aligned, and creating \
                                     a misaligned reference is undefined behavior (even if that \
@@ -98,7 +105,6 @@ impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> {
                                     reference with a raw pointer and use `read_unaligned`/`write_unaligned` \
                                     (loads and stores via `*p` must be properly aligned even when using raw pointers)"
                                 )
-                                .emit();
                         },
                     );
                 }
diff --git a/compiler/rustc_mir_transform/src/check_unsafety.rs b/compiler/rustc_mir_transform/src/check_unsafety.rs
index beff19a3a..f8f04214a 100644
--- a/compiler/rustc_mir_transform/src/check_unsafety.rs
+++ b/compiler/rustc_mir_transform/src/check_unsafety.rs
@@ -312,7 +312,7 @@ impl<'tcx> UnsafetyChecker<'_, 'tcx> {
                             } else if !place
                                 .ty(self.body, self.tcx)
                                 .ty
-                                .is_freeze(self.tcx.at(self.source_info.span), self.param_env)
+                                .is_freeze(self.tcx, self.param_env)
                             {
                                 UnsafetyViolationDetails::BorrowOfLayoutConstrainedField
                             } else {
@@ -489,21 +489,20 @@ fn unsafety_check_result<'tcx>(
 
 fn report_unused_unsafe(tcx: TyCtxt<'_>, kind: UnusedUnsafe, id: HirId) {
     let span = tcx.sess.source_map().guess_head_span(tcx.hir().span(id));
-    tcx.struct_span_lint_hir(UNUSED_UNSAFE, id, span, |lint| {
-        let msg = "unnecessary `unsafe` block";
-        let mut db = lint.build(msg);
-        db.span_label(span, msg);
+    let msg = "unnecessary `unsafe` block";
+    tcx.struct_span_lint_hir(UNUSED_UNSAFE, id, span, msg, |lint| {
+        lint.span_label(span, msg);
         match kind {
             UnusedUnsafe::Unused => {}
             UnusedUnsafe::InUnsafeBlock(id) => {
-                db.span_label(
+                lint.span_label(
                     tcx.sess.source_map().guess_head_span(tcx.hir().span(id)),
                     "because it's nested under this `unsafe` block",
                 );
             }
         }
 
-        db.emit();
+        lint
     });
 }
 
@@ -543,15 +542,8 @@ pub fn check_unsafety(tcx: TyCtxt<'_>, def_id: LocalDefId) {
                 UNSAFE_OP_IN_UNSAFE_FN,
                 lint_root,
                 source_info.span,
-                |lint| {
-                    lint.build(&format!(
-                        "{} is unsafe and requires unsafe block (error E0133)",
-                        description,
-                    ))
-                    .span_label(source_info.span, description)
-                    .note(note)
-                    .emit();
-                },
+                format!("{} is unsafe and requires unsafe block (error E0133)", description,),
+                |lint| lint.span_label(source_info.span, description).note(note),
             ),
         }
     }
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 7a2a15a84..4e4515888 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -17,7 +17,7 @@ use rustc_middle::mir::{
     RETURN_PLACE,
 };
 use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
+use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, ConstKind, Instance, ParamEnv, Ty, TyCtxt, TypeVisitable};
 use rustc_span::{def_id::DefId, Span};
 use rustc_target::abi::{self, HasDataLayout, Size, TargetDataLayout};
@@ -471,7 +471,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        self.ecx.mir_const_to_op(&c.literal, None).ok()
+        self.ecx.const_to_op(&c.literal, None).ok()
     }
 
     /// Returns the value, if any, of evaluating `place`.
@@ -633,7 +633,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         }
         if !rvalue
             .ty(&self.ecx.frame().body.local_decls, *self.ecx.tcx)
-            .is_sized(self.ecx.tcx, self.param_env)
+            .is_sized(*self.ecx.tcx, self.param_env)
         {
             // the interpreter doesn't support unsized locals (only unsized arguments),
             // but rustc does (in a kinda broken way), so we have to skip them here
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 37e78f4ac..479c4e577 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -16,12 +16,12 @@ use rustc_index::bit_set::BitSet;
 use rustc_index::vec::IndexVec;
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::{
-    AssertKind, BinOp, Body, Constant, ConstantKind, Local, LocalDecl, Location, Operand, Place,
-    Rvalue, SourceInfo, SourceScope, SourceScopeData, Statement, StatementKind, Terminator,
-    TerminatorKind, UnOp, RETURN_PLACE,
+    AssertKind, BinOp, Body, Constant, Local, LocalDecl, Location, Operand, Place, Rvalue,
+    SourceInfo, SourceScope, SourceScopeData, Statement, StatementKind, Terminator, TerminatorKind,
+    UnOp, RETURN_PLACE,
 };
 use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
+use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, ConstInt, Instance, ParamEnv, ScalarInt, Ty, TyCtxt, TypeVisitable};
 use rustc_session::lint;
 use rustc_span::Span;
@@ -286,39 +286,22 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
     }
 
     /// Returns the value, if any, of evaluating `c`.
-    fn eval_constant(&mut self, c: &Constant<'tcx>, source_info: SourceInfo) -> Option<OpTy<'tcx>> {
+    fn eval_constant(
+        &mut self,
+        c: &Constant<'tcx>,
+        _source_info: SourceInfo,
+    ) -> Option<OpTy<'tcx>> {
         // FIXME we need to revisit this for #67176
         if c.needs_subst() {
             return None;
         }
 
-        match self.ecx.mir_const_to_op(&c.literal, None) {
+        match self.ecx.const_to_op(&c.literal, None) {
             Ok(op) => Some(op),
             Err(error) => {
                 let tcx = self.ecx.tcx.at(c.span);
                 let err = ConstEvalErr::new(&self.ecx, error, Some(c.span));
-                if let Some(lint_root) = self.lint_root(source_info) {
-                    let lint_only = match c.literal {
-                        ConstantKind::Ty(ct) => ct.needs_subst(),
-                        ConstantKind::Unevaluated(
-                            ty::Unevaluated { def: _, substs: _, promoted: Some(_) },
-                            _,
-                        ) => {
-                            // Promoteds must lint and not error as the user didn't ask for them
-                            true
-                        }
-                        ConstantKind::Unevaluated(..) | ConstantKind::Val(..) => c.needs_subst(),
-                    };
-                    if lint_only {
-                        // Out of backwards compatibility we cannot report hard errors in unused
-                        // generic functions using associated constants of the generic parameters.
-                        err.report_as_lint(tcx, "erroneous constant used", lint_root, Some(c.span));
-                    } else {
-                        err.report_as_error(tcx, "erroneous constant used");
-                    }
-                } else {
-                    err.report_as_error(tcx, "erroneous constant used");
-                }
+                err.report_as_error(tcx, "erroneous constant used");
                 None
             }
         }
@@ -347,10 +330,8 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         panic: AssertKind<impl std::fmt::Debug>,
     ) {
         if let Some(lint_root) = self.lint_root(source_info) {
-            self.tcx.struct_span_lint_hir(lint, lint_root, source_info.span, |lint| {
-                let mut err = lint.build(message);
-                err.span_label(source_info.span, format!("{:?}", panic));
-                err.emit();
+            self.tcx.struct_span_lint_hir(lint, lint_root, source_info.span, message, |lint| {
+                lint.span_label(source_info.span, format!("{:?}", panic))
             });
         }
     }
@@ -519,7 +500,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         }
         if !rvalue
             .ty(&self.ecx.frame().body.local_decls, *self.ecx.tcx)
-            .is_sized(self.ecx.tcx, self.param_env)
+            .is_sized(*self.ecx.tcx, self.param_env)
         {
             // the interpreter doesn't support unsized locals (only unsized arguments),
             // but rustc does (in a kinda broken way), so we have to skip them here
diff --git a/compiler/rustc_mir_transform/src/coverage/test_macros/Cargo.toml b/compiler/rustc_mir_transform/src/coverage/test_macros/Cargo.toml
index f5e8b6565..f753caa91 100644
--- a/compiler/rustc_mir_transform/src/coverage/test_macros/Cargo.toml
+++ b/compiler/rustc_mir_transform/src/coverage/test_macros/Cargo.toml
@@ -5,4 +5,3 @@ edition = "2021"
 
 [lib]
 proc-macro = true
-doctest = false
diff --git a/compiler/rustc_mir_transform/src/deduce_param_attrs.rs b/compiler/rustc_mir_transform/src/deduce_param_attrs.rs
new file mode 100644
index 000000000..28b1c5a48
--- /dev/null
+++ b/compiler/rustc_mir_transform/src/deduce_param_attrs.rs
@@ -0,0 +1,248 @@
+//! Deduces supplementary parameter attributes from MIR.
+//!
+//! Deduced parameter attributes are those that can only be soundly determined by examining the
+//! body of the function instead of just the signature. These can be useful for optimization
+//! purposes on a best-effort basis. We compute them here and store them into the crate metadata so
+//! dependent crates can use them.
+
+use rustc_hir::def_id::DefId;
+use rustc_index::bit_set::BitSet;
+use rustc_middle::mir::visit::{NonMutatingUseContext, PlaceContext, Visitor};
+use rustc_middle::mir::{Body, Local, Location, Operand, Terminator, TerminatorKind, RETURN_PLACE};
+use rustc_middle::ty::{self, DeducedParamAttrs, ParamEnv, Ty, TyCtxt};
+use rustc_session::config::OptLevel;
+
+/// A visitor that determines which arguments have been mutated. We can't use the mutability field
+/// on LocalDecl for this because it has no meaning post-optimization.
+struct DeduceReadOnly {
+    /// Each bit is indexed by argument number, starting at zero (so 0 corresponds to local decl
+    /// 1). The bit is true if the argument may have been mutated or false if we know it hasn't
+    /// been up to the point we're at.
+    mutable_args: BitSet<usize>,
+}
+
+impl DeduceReadOnly {
+    /// Returns a new DeduceReadOnly instance.
+    fn new(arg_count: usize) -> Self {
+        Self { mutable_args: BitSet::new_empty(arg_count) }
+    }
+}
+
+impl<'tcx> Visitor<'tcx> for DeduceReadOnly {
+    fn visit_local(&mut self, local: Local, mut context: PlaceContext, _: Location) {
+        // We're only interested in arguments.
+        if local == RETURN_PLACE || local.index() > self.mutable_args.domain_size() {
+            return;
+        }
+
+        // Replace place contexts that are moves with copies. This is safe in all cases except
+        // function argument position, which we already handled in `visit_terminator()` by using the
+        // ArgumentChecker. See the comment in that method for more details.
+        //
+        // In the future, we might want to move this out into a separate pass, but for now let's
+        // just do it on the fly because that's faster.
+        if matches!(context, PlaceContext::NonMutatingUse(NonMutatingUseContext::Move)) {
+            context = PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy);
+        }
+
+        match context {
+            PlaceContext::MutatingUse(..)
+            | PlaceContext::NonMutatingUse(NonMutatingUseContext::Move) => {
+                // This is a mutation, so mark it as such.
+                self.mutable_args.insert(local.index() - 1);
+            }
+            PlaceContext::NonMutatingUse(..) | PlaceContext::NonUse(..) => {
+                // Not mutating, so it's fine.
+            }
+        }
+    }
+
+    fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
+        // OK, this is subtle. Suppose that we're trying to deduce whether `x` in `f` is read-only
+        // and we have the following:
+        //
+        //     fn f(x: BigStruct) { g(x) }
+        //     fn g(mut y: BigStruct) { y.foo = 1 }
+        //
+        // If, at the generated MIR level, `f` turned into something like:
+        //
+        //      fn f(_1: BigStruct) -> () {
+        //          let mut _0: ();
+        //          bb0: {
+        //              _0 = g(move _1) -> bb1;
+        //          }
+        //          ...
+        //      }
+        //
+        // then it would be incorrect to mark `x` (i.e. `_1`) as `readonly`, because `g`'s write to
+        // its copy of the indirect parameter would actually be a write directly to the pointer that
+        // `f` passes. Note that function arguments are the only situation in which this problem can
+        // arise: every other use of `move` in MIR doesn't actually write to the value it moves
+        // from.
+        //
+        // Anyway, right now this situation doesn't actually arise in practice. Instead, the MIR for
+        // that function looks like this:
+        //
+        //      fn f(_1: BigStruct) -> () {
+        //          let mut _0: ();
+        //          let mut _2: BigStruct;
+        //          bb0: {
+        //              _2 = move _1;
+        //              _0 = g(move _2) -> bb1;
+        //          }
+        //          ...
+        //      }
+        //
+        // Because of that extra move that MIR construction inserts, `x` (i.e. `_1`) can *in
+        // practice* safely be marked `readonly`.
+        //
+        // To handle the possibility that other optimizations (for example, destination propagation)
+        // might someday generate MIR like the first example above, we panic upon seeing an argument
+        // to *our* function that is directly moved into *another* function as an argument. Having
+        // eliminated that problematic case, we can safely treat moves as copies in this analysis.
+        //
+        // In the future, if MIR optimizations cause arguments of a caller to be directly moved into
+        // the argument of a callee, we can just add that argument to `mutated_args` instead of
+        // panicking.
+        //
+        // Note that, because the problematic MIR is never actually generated, we can't add a test
+        // case for this.
+
+        if let TerminatorKind::Call { ref args, .. } = terminator.kind {
+            for arg in args {
+                if let Operand::Move(_) = *arg {
+                    // ArgumentChecker panics if a direct move of an argument from a caller to a
+                    // callee was detected.
+                    //
+                    // If, in the future, MIR optimizations cause arguments to be moved directly
+                    // from callers to callees, change the panic to instead add the argument in
+                    // question to `mutating_uses`.
+                    ArgumentChecker::new(self.mutable_args.domain_size())
+                        .visit_operand(arg, location)
+                }
+            }
+        };
+
+        self.super_terminator(terminator, location);
+    }
+}
+
+/// A visitor that simply panics if a direct move of an argument from a caller to a callee was
+/// detected.
+struct ArgumentChecker {
+    /// The number of arguments to the calling function.
+    arg_count: usize,
+}
+
+impl ArgumentChecker {
+    /// Creates a new ArgumentChecker.
+    fn new(arg_count: usize) -> Self {
+        Self { arg_count }
+    }
+}
+
+impl<'tcx> Visitor<'tcx> for ArgumentChecker {
+    fn visit_local(&mut self, local: Local, context: PlaceContext, _: Location) {
+        // Check to make sure that, if this local is an argument, we didn't move directly from it.
+        if matches!(context, PlaceContext::NonMutatingUse(NonMutatingUseContext::Move))
+            && local != RETURN_PLACE
+            && local.index() <= self.arg_count
+        {
+            // If, in the future, MIR optimizations cause arguments to be moved directly from
+            // callers to callees, change this panic to instead add the argument in question to
+            // `mutating_uses`.
+            panic!("Detected a direct move from a caller's argument to a callee's argument!")
+        }
+    }
+}
+
+/// Returns true if values of a given type will never be passed indirectly, regardless of ABI.
+fn type_will_always_be_passed_directly<'tcx>(ty: Ty<'tcx>) -> bool {
+    matches!(
+        ty.kind(),
+        ty::Bool
+            | ty::Char
+            | ty::Float(..)
+            | ty::Int(..)
+            | ty::RawPtr(..)
+            | ty::Ref(..)
+            | ty::Slice(..)
+            | ty::Uint(..)
+    )
+}
+
+/// Returns the deduced parameter attributes for a function.
+///
+/// Deduced parameter attributes are those that can only be soundly determined by examining the
+/// body of the function instead of just the signature. These can be useful for optimization
+/// purposes on a best-effort basis. We compute them here and store them into the crate metadata so
+/// dependent crates can use them.
+pub fn deduced_param_attrs<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx [DeducedParamAttrs] {
+    // This computation is unfortunately rather expensive, so don't do it unless we're optimizing.
+    // Also skip it in incremental mode.
+    if tcx.sess.opts.optimize == OptLevel::No || tcx.sess.opts.incremental.is_some() {
+        return &[];
+    }
+
+    // If the Freeze language item isn't present, then don't bother.
+    if tcx.lang_items().freeze_trait().is_none() {
+        return &[];
+    }
+
+    // Codegen won't use this information for anything if all the function parameters are passed
+    // directly. Detect that and bail, for compilation speed.
+    let fn_ty = tcx.type_of(def_id);
+    if matches!(fn_ty.kind(), ty::FnDef(..)) {
+        if fn_ty
+            .fn_sig(tcx)
+            .inputs()
+            .skip_binder()
+            .iter()
+            .cloned()
+            .all(type_will_always_be_passed_directly)
+        {
+            return &[];
+        }
+    }
+
+    // Don't deduce any attributes for functions that have no MIR.
+    if !tcx.is_mir_available(def_id) {
+        return &[];
+    }
+
+    // Deduced attributes for other crates should be read from the metadata instead of via this
+    // function.
+    debug_assert!(def_id.is_local());
+
+    // Grab the optimized MIR. Analyze it to determine which arguments have been mutated.
+    let body: &Body<'tcx> = tcx.optimized_mir(def_id);
+    let mut deduce_read_only = DeduceReadOnly::new(body.arg_count);
+    deduce_read_only.visit_body(body);
+
+    // Set the `readonly` attribute for every argument that we concluded is immutable and that
+    // contains no UnsafeCells.
+    //
+    // FIXME: This is overly conservative around generic parameters: `is_freeze()` will always
+    // return false for them. For a description of alternatives that could do a better job here,
+    // see [1].
+    //
+    // [1]: https://github.com/rust-lang/rust/pull/103172#discussion_r999139997
+    let mut deduced_param_attrs = tcx.arena.alloc_from_iter(
+        body.local_decls.iter().skip(1).take(body.arg_count).enumerate().map(
+            |(arg_index, local_decl)| DeducedParamAttrs {
+                read_only: !deduce_read_only.mutable_args.contains(arg_index)
+                    && local_decl.ty.is_freeze(tcx, ParamEnv::reveal_all()),
+            },
+        ),
+    );
+
+    // Trailing parameters past the size of the `deduced_param_attrs` array are assumed to have the
+    // default set of attributes, so we don't have to store them explicitly. Pop them off to save a
+    // few bytes in metadata.
+    while deduced_param_attrs.last() == Some(&DeducedParamAttrs::default()) {
+        let last_index = deduced_param_attrs.len() - 1;
+        deduced_param_attrs = &mut deduced_param_attrs[0..last_index];
+    }
+
+    deduced_param_attrs
+}
diff --git a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
index 294af2455..ef8d6bb65 100644
--- a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
@@ -8,7 +8,6 @@ use rustc_index::vec::Idx;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::MutVisitor;
 use rustc_middle::mir::*;
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{Ty, TyCtxt};
 
 /// Constructs the types used when accessing a Box's pointer
diff --git a/compiler/rustc_mir_transform/src/ffi_unwind_calls.rs b/compiler/rustc_mir_transform/src/ffi_unwind_calls.rs
index 7522a50a8..1244c1802 100644
--- a/compiler/rustc_mir_transform/src/ffi_unwind_calls.rs
+++ b/compiler/rustc_mir_transform/src/ffi_unwind_calls.rs
@@ -106,14 +106,12 @@ fn has_ffi_unwind_calls(tcx: TyCtxt<'_>, local_def_id: LocalDefId) -> bool {
                 .lint_root;
             let span = terminator.source_info.span;
 
-            tcx.struct_span_lint_hir(FFI_UNWIND_CALLS, lint_root, span, |lint| {
-                let msg = match fn_def_id {
-                    Some(_) => "call to foreign function with FFI-unwind ABI",
-                    None => "call to function pointer with FFI-unwind ABI",
-                };
-                let mut db = lint.build(msg);
-                db.span_label(span, msg);
-                db.emit();
+            let msg = match fn_def_id {
+                Some(_) => "call to foreign function with FFI-unwind ABI",
+                None => "call to function pointer with FFI-unwind ABI",
+            };
+            tcx.struct_span_lint_hir(FFI_UNWIND_CALLS, lint_root, span, msg, |lint| {
+                lint.span_label(span, msg)
             });
 
             tainted = true;
diff --git a/compiler/rustc_mir_transform/src/function_item_references.rs b/compiler/rustc_mir_transform/src/function_item_references.rs
index 2e4fe1e3e..469566694 100644
--- a/compiler/rustc_mir_transform/src/function_item_references.rs
+++ b/compiler/rustc_mir_transform/src/function_item_references.rs
@@ -3,11 +3,7 @@ use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::*;
-use rustc_middle::ty::{
-    self,
-    subst::{GenericArgKind, Subst, SubstsRef},
-    EarlyBinder, PredicateKind, Ty, TyCtxt,
-};
+use rustc_middle::ty::{self, EarlyBinder, GenericArgKind, PredicateKind, SubstsRef, Ty, TyCtxt};
 use rustc_session::lint::builtin::FUNCTION_ITEM_REFERENCES;
 use rustc_span::{symbol::sym, Span};
 use rustc_target::spec::abi::Abi;
@@ -183,11 +179,15 @@ impl<'tcx> FunctionItemRefChecker<'_, 'tcx> {
         let num_args = fn_sig.inputs().map_bound(|inputs| inputs.len()).skip_binder();
         let variadic = if fn_sig.c_variadic() { ", ..." } else { "" };
         let ret = if fn_sig.output().skip_binder().is_unit() { "" } else { " -> _" };
-        self.tcx.struct_span_lint_hir(FUNCTION_ITEM_REFERENCES, lint_root, span, |lint| {
-            lint.build("taking a reference to a function item does not give a function pointer")
-                .span_suggestion(
+        self.tcx.struct_span_lint_hir(
+            FUNCTION_ITEM_REFERENCES,
+            lint_root,
+            span,
+            "taking a reference to a function item does not give a function pointer",
+            |lint| {
+                lint.span_suggestion(
                     span,
-                    &format!("cast `{}` to obtain a function pointer", ident),
+                    format!("cast `{}` to obtain a function pointer", ident),
                     format!(
                         "{} as {}{}fn({}{}){}",
                         if params.is_empty() { ident } else { format!("{}::<{}>", ident, params) },
@@ -199,7 +199,7 @@ impl<'tcx> FunctionItemRefChecker<'_, 'tcx> {
                     ),
                     Applicability::Unspecified,
                 )
-                .emit();
-        });
+            },
+        );
     }
 }
diff --git a/compiler/rustc_mir_transform/src/generator.rs b/compiler/rustc_mir_transform/src/generator.rs
index 705cf776f..c833de3a8 100644
--- a/compiler/rustc_mir_transform/src/generator.rs
+++ b/compiler/rustc_mir_transform/src/generator.rs
@@ -61,9 +61,8 @@ use rustc_index::vec::{Idx, IndexVec};
 use rustc_middle::mir::dump_mir;
 use rustc_middle::mir::visit::{MutVisitor, PlaceContext, Visitor};
 use rustc_middle::mir::*;
-use rustc_middle::ty::subst::{Subst, SubstsRef};
-use rustc_middle::ty::GeneratorSubsts;
 use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt};
+use rustc_middle::ty::{GeneratorSubsts, SubstsRef};
 use rustc_mir_dataflow::impls::{
     MaybeBorrowedLocals, MaybeLiveLocals, MaybeRequiresStorage, MaybeStorageLive,
 };
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index d00a384cb..780b91d92 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -7,7 +7,6 @@ use rustc_index::vec::Idx;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
 use rustc_session::config::OptLevel;
 use rustc_span::def_id::DefId;
@@ -606,7 +605,7 @@ impl<'tcx> Inliner<'tcx> {
                 caller_body.required_consts.extend(
                     callee_body.required_consts.iter().copied().filter(|&ct| match ct.literal {
                         ConstantKind::Ty(_) => {
-                            bug!("should never encounter ty::Unevaluated in `required_consts`")
+                            bug!("should never encounter ty::UnevaluatedConst in `required_consts`")
                         }
                         ConstantKind::Val(..) | ConstantKind::Unevaluated(..) => true,
                     }),
@@ -978,6 +977,21 @@ impl Integrator<'_, '_> {
         trace!("mapping block `{:?}` to `{:?}`", block, new);
         new
     }
+
+    fn map_unwind(&self, unwind: Option<BasicBlock>) -> Option<BasicBlock> {
+        if self.in_cleanup_block {
+            if unwind.is_some() {
+                bug!("cleanup on cleanup block");
+            }
+            return unwind;
+        }
+
+        match unwind {
+            Some(target) => Some(self.map_block(target)),
+            // Add an unwind edge to the original call's cleanup block
+            None => self.cleanup_block,
+        }
+    }
 }
 
 impl<'tcx> MutVisitor<'tcx> for Integrator<'_, 'tcx> {
@@ -1086,35 +1100,17 @@ impl<'tcx> MutVisitor<'tcx> for Integrator<'_, 'tcx> {
             TerminatorKind::Drop { ref mut target, ref mut unwind, .. }
             | TerminatorKind::DropAndReplace { ref mut target, ref mut unwind, .. } => {
                 *target = self.map_block(*target);
-                if let Some(tgt) = *unwind {
-                    *unwind = Some(self.map_block(tgt));
-                } else if !self.in_cleanup_block {
-                    // Unless this drop is in a cleanup block, add an unwind edge to
-                    // the original call's cleanup block
-                    *unwind = self.cleanup_block;
-                }
+                *unwind = self.map_unwind(*unwind);
             }
             TerminatorKind::Call { ref mut target, ref mut cleanup, .. } => {
                 if let Some(ref mut tgt) = *target {
                     *tgt = self.map_block(*tgt);
                 }
-                if let Some(tgt) = *cleanup {
-                    *cleanup = Some(self.map_block(tgt));
-                } else if !self.in_cleanup_block {
-                    // Unless this call is in a cleanup block, add an unwind edge to
-                    // the original call's cleanup block
-                    *cleanup = self.cleanup_block;
-                }
+                *cleanup = self.map_unwind(*cleanup);
             }
             TerminatorKind::Assert { ref mut target, ref mut cleanup, .. } => {
                 *target = self.map_block(*target);
-                if let Some(tgt) = *cleanup {
-                    *cleanup = Some(self.map_block(tgt));
-                } else if !self.in_cleanup_block {
-                    // Unless this assert is in a cleanup block, add an unwind edge to
-                    // the original call's cleanup block
-                    *cleanup = self.cleanup_block;
-                }
+                *cleanup = self.map_unwind(*cleanup);
             }
             TerminatorKind::Return => {
                 terminator.kind = if let Some(tgt) = self.callsite.target {
@@ -1142,11 +1138,8 @@ impl<'tcx> MutVisitor<'tcx> for Integrator<'_, 'tcx> {
             TerminatorKind::InlineAsm { ref mut destination, ref mut cleanup, .. } => {
                 if let Some(ref mut tgt) = *destination {
                     *tgt = self.map_block(*tgt);
-                } else if !self.in_cleanup_block {
-                    // Unless this inline asm is in a cleanup block, add an unwind edge to
-                    // the original call's cleanup block
-                    *cleanup = self.cleanup_block;
                 }
+                *cleanup = self.map_unwind(*cleanup);
             }
         }
     }
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index e6fc85595..5be223254 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -1,7 +1,6 @@
 #![allow(rustc::potential_query_instability)]
 #![feature(box_patterns)]
 #![feature(let_chains)]
-#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(never_type)]
@@ -57,6 +56,7 @@ mod const_prop_lint;
 mod coverage;
 mod dead_store_elimination;
 mod deaggregator;
+mod deduce_param_attrs;
 mod deduplicate_blocks;
 mod deref_separator;
 mod dest_prop;
@@ -71,7 +71,6 @@ mod inline;
 mod instcombine;
 mod lower_intrinsics;
 mod lower_slice_len;
-mod marker;
 mod match_branches;
 mod multiple_return_terminators;
 mod normalize_array_len;
@@ -140,6 +139,7 @@ pub fn provide(providers: &mut Providers) {
         promoted_mir_of_const_arg: |tcx, (did, param_did)| {
             promoted_mir(tcx, ty::WithOptConstParam { did, const_param_did: Some(param_did) })
         },
+        deduced_param_attrs: deduce_param_attrs::deduced_param_attrs,
         ..*providers
     };
 }
@@ -302,6 +302,7 @@ fn mir_const<'tcx>(
             &simplify::SimplifyCfg::new("initial"),
             &rustc_peek::SanityCheck, // Just a lint
         ],
+        None,
     );
     tcx.alloc_steal_mir(body)
 }
@@ -341,6 +342,7 @@ fn mir_promoted<'tcx>(
             &simplify::SimplifyCfg::new("promote-consts"),
             &coverage::InstrumentCoverage,
         ],
+        Some(MirPhase::Analysis(AnalysisPhase::Initial)),
     );
 
     let promoted = promote_pass.promoted_fragments.into_inner();
@@ -408,10 +410,8 @@ fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -
             pm::run_passes(
                 tcx,
                 &mut body,
-                &[
-                    &const_prop::ConstProp,
-                    &marker::PhaseChange(MirPhase::Runtime(RuntimePhase::Optimized)),
-                ],
+                &[&const_prop::ConstProp],
+                Some(MirPhase::Runtime(RuntimePhase::Optimized)),
             );
         }
     }
@@ -473,6 +473,7 @@ fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>
                 &remove_uninit_drops::RemoveUninitDrops,
                 &simplify::SimplifyCfg::new("remove-false-edges"),
             ],
+            None,
         );
         check_consts::post_drop_elaboration::check_live_drops(tcx, &body); // FIXME: make this a MIR lint
     }
@@ -497,10 +498,9 @@ fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         &cleanup_post_borrowck::CleanupNonCodegenStatements,
         &simplify::SimplifyCfg::new("early-opt"),
         &deref_separator::Derefer,
-        &marker::PhaseChange(MirPhase::Analysis(AnalysisPhase::PostCleanup)),
     ];
 
-    pm::run_passes(tcx, body, passes);
+    pm::run_passes(tcx, body, passes, Some(MirPhase::Analysis(AnalysisPhase::PostCleanup)));
 }
 
 /// Returns the sequence of passes that lowers analysis to runtime MIR.
@@ -525,9 +525,8 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         // CTFE support for aggregates.
         &deaggregator::Deaggregator,
         &Lint(const_prop_lint::ConstProp),
-        &marker::PhaseChange(MirPhase::Runtime(RuntimePhase::Initial)),
     ];
-    pm::run_passes_no_validate(tcx, body, passes);
+    pm::run_passes_no_validate(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::Initial)));
 }
 
 /// Returns the sequence of passes that do the initial cleanup of runtime MIR.
@@ -536,10 +535,9 @@ fn run_runtime_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         &elaborate_box_derefs::ElaborateBoxDerefs,
         &lower_intrinsics::LowerIntrinsics,
         &simplify::SimplifyCfg::new("elaborate-drops"),
-        &marker::PhaseChange(MirPhase::Runtime(RuntimePhase::PostCleanup)),
     ];
 
-    pm::run_passes(tcx, body, passes);
+    pm::run_passes(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::PostCleanup)));
 }
 
 fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
@@ -590,10 +588,10 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
             &deduplicate_blocks::DeduplicateBlocks,
             // Some cleanup necessary at least for LLVM and potentially other codegen backends.
             &add_call_guards::CriticalCallEdges,
-            &marker::PhaseChange(MirPhase::Runtime(RuntimePhase::Optimized)),
             // Dump the end result for testing and debugging purposes.
             &dump_mir::Marker("PreCodegen"),
         ],
+        Some(MirPhase::Runtime(RuntimePhase::Optimized)),
     );
 }
 
diff --git a/compiler/rustc_mir_transform/src/marker.rs b/compiler/rustc_mir_transform/src/marker.rs
deleted file mode 100644
index 06819fc1d..000000000
--- a/compiler/rustc_mir_transform/src/marker.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-use std::borrow::Cow;
-
-use crate::MirPass;
-use rustc_middle::mir::{Body, MirPhase};
-use rustc_middle::ty::TyCtxt;
-
-/// Changes the MIR phase without changing the MIR itself.
-pub struct PhaseChange(pub MirPhase);
-
-impl<'tcx> MirPass<'tcx> for PhaseChange {
-    fn phase_change(&self) -> Option<MirPhase> {
-        Some(self.0)
-    }
-
-    fn name(&self) -> Cow<'_, str> {
-        Cow::from(format!("PhaseChange-{:?}", self.0))
-    }
-
-    fn run_pass(&self, _: TyCtxt<'tcx>, _body: &mut Body<'tcx>) {}
-}
diff --git a/compiler/rustc_mir_transform/src/pass_manager.rs b/compiler/rustc_mir_transform/src/pass_manager.rs
index 67dae7146..230c6a7cb 100644
--- a/compiler/rustc_mir_transform/src/pass_manager.rs
+++ b/compiler/rustc_mir_transform/src/pass_manager.rs
@@ -66,10 +66,6 @@ where
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         self.1.run_pass(tcx, body)
     }
-
-    fn phase_change(&self) -> Option<MirPhase> {
-        self.1.phase_change()
-    }
 }
 
 /// Run the sequence of passes without validating the MIR after each pass. The MIR is still
@@ -78,23 +74,28 @@ pub fn run_passes_no_validate<'tcx>(
     tcx: TyCtxt<'tcx>,
     body: &mut Body<'tcx>,
     passes: &[&dyn MirPass<'tcx>],
+    phase_change: Option<MirPhase>,
 ) {
-    run_passes_inner(tcx, body, passes, false);
+    run_passes_inner(tcx, body, passes, phase_change, false);
 }
 
-pub fn run_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, passes: &[&dyn MirPass<'tcx>]) {
-    run_passes_inner(tcx, body, passes, true);
+/// The optional `phase_change` is applied after executing all the passes, if present
+pub fn run_passes<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    body: &mut Body<'tcx>,
+    passes: &[&dyn MirPass<'tcx>],
+    phase_change: Option<MirPhase>,
+) {
+    run_passes_inner(tcx, body, passes, phase_change, true);
 }
 
 fn run_passes_inner<'tcx>(
     tcx: TyCtxt<'tcx>,
     body: &mut Body<'tcx>,
     passes: &[&dyn MirPass<'tcx>],
+    phase_change: Option<MirPhase>,
     validate_each: bool,
 ) {
-    let start_phase = body.phase;
-    let mut cnt = 0;
-
     let validate = validate_each & tcx.sess.opts.unstable_opts.validate_mir;
     let overridden_passes = &tcx.sess.opts.unstable_opts.mir_enable_passes;
     trace!(?overridden_passes);
@@ -102,7 +103,6 @@ fn run_passes_inner<'tcx>(
     for pass in passes {
         let name = pass.name();
 
-        // Gather information about what we should be doing for this pass
         let overridden =
             overridden_passes.iter().rev().find(|(s, _)| s == &*name).map(|(_name, polarity)| {
                 trace!(
@@ -112,32 +112,44 @@ fn run_passes_inner<'tcx>(
                 );
                 *polarity
             });
-        let is_enabled = overridden.unwrap_or_else(|| pass.is_enabled(&tcx.sess));
-        let new_phase = pass.phase_change();
-        let dump_enabled = (is_enabled && pass.is_mir_dump_enabled()) || new_phase.is_some();
-        let validate = (validate && is_enabled)
-            || new_phase == Some(MirPhase::Runtime(RuntimePhase::Optimized));
+        if !overridden.unwrap_or_else(|| pass.is_enabled(&tcx.sess)) {
+            continue;
+        }
+
+        let dump_enabled = pass.is_mir_dump_enabled();
 
         if dump_enabled {
-            dump_mir(tcx, body, start_phase, &name, cnt, false);
-        }
-        if is_enabled {
-            pass.run_pass(tcx, body);
+            dump_mir_for_pass(tcx, body, &name, false);
         }
-        if dump_enabled {
-            dump_mir(tcx, body, start_phase, &name, cnt, true);
-            cnt += 1;
+        if validate {
+            validate_body(tcx, body, format!("before pass {}", name));
         }
-        if let Some(new_phase) = pass.phase_change() {
-            if body.phase >= new_phase {
-                panic!("Invalid MIR phase transition from {:?} to {:?}", body.phase, new_phase);
-            }
 
-            body.phase = new_phase;
+        pass.run_pass(tcx, body);
+
+        if dump_enabled {
+            dump_mir_for_pass(tcx, body, &name, true);
         }
         if validate {
             validate_body(tcx, body, format!("after pass {}", name));
         }
+
+        body.pass_count += 1;
+    }
+
+    if let Some(new_phase) = phase_change {
+        if body.phase >= new_phase {
+            panic!("Invalid MIR phase transition from {:?} to {:?}", body.phase, new_phase);
+        }
+
+        body.phase = new_phase;
+
+        dump_mir_for_phase_change(tcx, body);
+        if validate || new_phase == MirPhase::Runtime(RuntimePhase::Optimized) {
+            validate_body(tcx, body, format!("after phase change to {}", new_phase));
+        }
+
+        body.pass_count = 1;
     }
 }
 
@@ -145,22 +157,33 @@ pub fn validate_body<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, when: Strin
     validate::Validator { when, mir_phase: body.phase }.run_pass(tcx, body);
 }
 
-pub fn dump_mir<'tcx>(
+pub fn dump_mir_for_pass<'tcx>(
     tcx: TyCtxt<'tcx>,
     body: &Body<'tcx>,
-    phase: MirPhase,
     pass_name: &str,
-    cnt: usize,
     is_after: bool,
 ) {
-    let phase_index = phase.phase_index();
+    let phase_index = body.phase.phase_index();
 
     mir::dump_mir(
         tcx,
-        Some(&format_args!("{:03}-{:03}", phase_index, cnt)),
+        Some(&format_args!("{:03}-{:03}", phase_index, body.pass_count)),
         pass_name,
         if is_after { &"after" } else { &"before" },
         body,
         |_, _| Ok(()),
     );
 }
+
+pub fn dump_mir_for_phase_change<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
+    let phase_index = body.phase.phase_index();
+
+    mir::dump_mir(
+        tcx,
+        Some(&format_args!("{:03}-000", phase_index)),
+        &format!("{}", body.phase),
+        &"after",
+        body,
+        |_, _| Ok(()),
+    )
+}
diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs
index 882136200..4e8798b7a 100644
--- a/compiler/rustc_mir_transform/src/shim.rs
+++ b/compiler/rustc_mir_transform/src/shim.rs
@@ -3,7 +3,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::mir::*;
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
+use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, EarlyBinder, GeneratorSubsts, Ty, TyCtxt};
 use rustc_target::abi::VariantIdx;
 
@@ -17,7 +17,7 @@ use std::iter;
 
 use crate::util::expand_aggregate;
 use crate::{
-    abort_unwinding_calls, add_call_guards, add_moves_for_packed_drops, deref_separator, marker,
+    abort_unwinding_calls, add_call_guards, add_moves_for_packed_drops, deref_separator,
     pass_manager as pm, remove_noop_landing_pads, simplify,
 };
 use rustc_middle::mir::patch::MirPatch;
@@ -97,8 +97,8 @@ fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> Body<'
             &simplify::SimplifyCfg::new("make_shim"),
             &add_call_guards::CriticalCallEdges,
             &abort_unwinding_calls::AbortUnwindingCalls,
-            &marker::PhaseChange(MirPhase::Runtime(RuntimePhase::Optimized)),
         ],
+        Some(MirPhase::Runtime(RuntimePhase::Optimized)),
     );
 
     debug!("make_shim({:?}) = {:?}", instance, result);
@@ -312,7 +312,7 @@ fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -
     let param_env = tcx.param_env(def_id);
 
     let mut builder = CloneShimBuilder::new(tcx, def_id, self_ty);
-    let is_copy = self_ty.is_copy_modulo_regions(tcx.at(builder.span), param_env);
+    let is_copy = self_ty.is_copy_modulo_regions(tcx, param_env);
 
     let dest = Place::return_place();
     let src = tcx.mk_place_deref(Place::from(Local::new(1 + 0)));