Auto merge of #76771 - Dylan-DPC:rollup-qj4j3ma, r=Dylan-DPC

Rollup of 10 pull requests

Successful merges:

 - #73955 (deny(unsafe_op_in_unsafe_fn) in libstd/process.rs)
 - #75146 (Detect overflow in proc_macro_server subspan)
 - #75304 (Note when a a move/borrow error is caused by a deref coercion)
 - #75749 (Consolidate some duplicate code in the sys modules.)
 - #75882 (Use translated variable for test string)
 - #75886 (Test that bounds checks are elided for [..index] after .position())
 - #76048 (Initial support for riscv32gc_unknown_linux_gnu)
 - #76198 (Make some Ordering methods const)
 - #76689 (Upgrade to pulldown-cmark 0.8.0)
 - #76763 (Update cargo)

Failed merges:

r? `@ghost`

57 files changed, 563 insertions, 972 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 9b5a4c24d25..d3f777bc663 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -534,7 +534,7 @@ dependencies = [
  "if_chain",
  "itertools 0.9.0",
  "lazy_static",
- "pulldown-cmark",
+ "pulldown-cmark 0.7.2",
  "quine-mc_cluskey",
  "quote",
  "regex-syntax",
@@ -1853,7 +1853,7 @@ dependencies = [
  "log",
  "memchr",
  "open",
- "pulldown-cmark",
+ "pulldown-cmark 0.7.2",
  "regex",
  "serde",
  "serde_derive",
@@ -2512,6 +2512,17 @@ dependencies = [
 ]
 
 [[package]]
+name = "pulldown-cmark"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffade02495f22453cd593159ea2f59827aae7f53fa8323f756799b670881dcf8"
+dependencies = [
+ "bitflags",
+ "memchr",
+ "unicase",
+]
+
+[[package]]
 name = "punycode"
 version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -4122,7 +4133,7 @@ dependencies = [
  "expect-test",
  "itertools 0.9.0",
  "minifier",
- "pulldown-cmark",
+ "pulldown-cmark 0.8.0",
  "rustc-rayon",
  "serde",
  "serde_json",
diff --git a/compiler/rustc_expand/src/proc_macro_server.rs b/compiler/rustc_expand/src/proc_macro_server.rs
index ec41fd7a3ee..4cfb188783b 100644
--- a/compiler/rustc_expand/src/proc_macro_server.rs
+++ b/compiler/rustc_expand/src/proc_macro_server.rs
@@ -584,12 +584,12 @@ impl server::Literal for Rustc<'_> {
 
         let start = match start {
             Bound::Included(lo) => lo,
-            Bound::Excluded(lo) => lo + 1,
+            Bound::Excluded(lo) => lo.checked_add(1)?,
             Bound::Unbounded => 0,
         };
 
         let end = match end {
-            Bound::Included(hi) => hi + 1,
+            Bound::Included(hi) => hi.checked_add(1)?,
             Bound::Excluded(hi) => hi,
             Bound::Unbounded => length,
         };
diff --git a/compiler/rustc_middle/src/ty/adjustment.rs b/compiler/rustc_middle/src/ty/adjustment.rs
index 6a9bb8d6c28..46ef5ff7dd8 100644
--- a/compiler/rustc_middle/src/ty/adjustment.rs
+++ b/compiler/rustc_middle/src/ty/adjustment.rs
@@ -4,6 +4,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_macros::HashStable;
+use rustc_span::Span;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
 pub enum PointerCast {
@@ -113,6 +114,9 @@ pub enum Adjust<'tcx> {
 pub struct OverloadedDeref<'tcx> {
     pub region: ty::Region<'tcx>,
     pub mutbl: hir::Mutability,
+    /// The `Span` associated with the field access or method call
+    /// that triggered this overloaded deref.
+    pub span: Span,
 }
 
 impl<'tcx> OverloadedDeref<'tcx> {
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index afbf805975c..6d9d23836fc 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -612,8 +612,11 @@ impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::Adjust<'a> {
 impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::OverloadedDeref<'a> {
     type Lifted = ty::adjustment::OverloadedDeref<'tcx>;
     fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(&self.region)
-            .map(|region| ty::adjustment::OverloadedDeref { region, mutbl: self.mutbl })
+        tcx.lift(&self.region).map(|region| ty::adjustment::OverloadedDeref {
+            region,
+            mutbl: self.mutbl,
+            span: self.span,
+        })
     }
 }
 
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
index 676065007b7..11122b195c0 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
@@ -66,7 +66,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let span = use_spans.args_or_use();
 
         let move_site_vec = self.get_moved_indexes(location, mpi);
-        debug!("report_use_of_moved_or_uninitialized: move_site_vec={:?}", move_site_vec);
+        debug!(
+            "report_use_of_moved_or_uninitialized: move_site_vec={:?} use_spans={:?}",
+            move_site_vec, use_spans
+        );
         let move_out_indices: Vec<_> =
             move_site_vec.iter().map(|move_site| move_site.moi).collect();
 
@@ -229,6 +232,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                     );
                                 }
                             }
+                            // Deref::deref takes &self, which cannot cause a move
+                            FnSelfUseKind::DerefCoercion { .. } => unreachable!(),
                         }
                     } else {
                         err.span_label(
@@ -355,6 +360,20 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 self.note_type_does_not_implement_copy(&mut err, &note_msg, ty, span, partial_str);
             }
 
+            if let UseSpans::FnSelfUse {
+                kind: FnSelfUseKind::DerefCoercion { deref_target, deref_target_ty },
+                ..
+            } = use_spans
+            {
+                err.note(&format!(
+                    "{} occurs due to deref coercion to `{}`",
+                    desired_action.as_noun(),
+                    deref_target_ty
+                ));
+
+                err.span_note(deref_target, "deref defined here");
+            }
+
             if let Some((_, mut old_err)) =
                 self.move_error_reported.insert(move_out_indices, (used_place, err))
             {
@@ -945,7 +964,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         name: &str,
         borrow: &BorrowData<'tcx>,
         drop_span: Span,
-        borrow_spans: UseSpans,
+        borrow_spans: UseSpans<'tcx>,
         explanation: BorrowExplanation,
     ) -> DiagnosticBuilder<'cx> {
         debug!(
@@ -1146,7 +1165,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         location: Location,
         borrow: &BorrowData<'tcx>,
         drop_span: Span,
-        borrow_spans: UseSpans,
+        borrow_spans: UseSpans<'tcx>,
         proper_span: Span,
         explanation: BorrowExplanation,
     ) -> DiagnosticBuilder<'cx> {
@@ -1274,7 +1293,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
     fn report_escaping_closure_capture(
         &mut self,
-        use_span: UseSpans,
+        use_span: UseSpans<'tcx>,
         var_span: Span,
         fr_name: &RegionName,
         category: ConstraintCategory,
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/explain_borrow.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/explain_borrow.rs
index eaaf202f3bd..eccb6168229 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/explain_borrow.rs
@@ -501,7 +501,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     fn later_use_kind(
         &self,
         borrow: &BorrowData<'tcx>,
-        use_spans: UseSpans,
+        use_spans: UseSpans<'tcx>,
         location: Location,
     ) -> (LaterUseKind, Span) {
         match use_spans {
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs
index 3cee32834be..4256f6e39d5 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs
@@ -11,7 +11,7 @@ use rustc_middle::mir::{
     PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind,
 };
 use rustc_middle::ty::print::Print;
-use rustc_middle::ty::{self, DefIdTree, Ty, TyCtxt};
+use rustc_middle::ty::{self, DefIdTree, Instance, Ty, TyCtxt};
 use rustc_span::{
     hygiene::{DesugaringKind, ForLoopLoc},
     symbol::sym,
@@ -538,7 +538,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
 /// The span(s) associated to a use of a place.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub(super) enum UseSpans {
+pub(super) enum UseSpans<'tcx> {
     /// The access is caused by capturing a variable for a closure.
     ClosureUse {
         /// This is true if the captured variable was from a generator.
@@ -558,7 +558,7 @@ pub(super) enum UseSpans {
         fn_call_span: Span,
         /// The definition span of the method being called
         fn_span: Span,
-        kind: FnSelfUseKind,
+        kind: FnSelfUseKind<'tcx>,
     },
     /// This access is caused by a `match` or `if let` pattern.
     PatUse(Span),
@@ -567,22 +567,32 @@ pub(super) enum UseSpans {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub(super) enum FnSelfUseKind {
+pub(super) enum FnSelfUseKind<'tcx> {
     /// A normal method call of the form `receiver.foo(a, b, c)`
     Normal { self_arg: Ident, implicit_into_iter: bool },
     /// A call to `FnOnce::call_once`, desugared from `my_closure(a, b, c)`
     FnOnceCall,
     /// A call to an operator trait, desuraged from operator syntax (e.g. `a << b`)
     Operator { self_arg: Ident },
+    DerefCoercion {
+        /// The `Span` of the `Target` associated type
+        /// in the `Deref` impl we are using.
+        deref_target: Span,
+        /// The type `T::Deref` we are dereferencing to
+        deref_target_ty: Ty<'tcx>,
+    },
 }
 
-impl UseSpans {
+impl UseSpans<'_> {
     pub(super) fn args_or_use(self) -> Span {
         match self {
             UseSpans::ClosureUse { args_span: span, .. }
             | UseSpans::PatUse(span)
-            | UseSpans::FnSelfUse { var_span: span, .. }
             | UseSpans::OtherUse(span) => span,
+            UseSpans::FnSelfUse {
+                fn_call_span, kind: FnSelfUseKind::DerefCoercion { .. }, ..
+            } => fn_call_span,
+            UseSpans::FnSelfUse { var_span, .. } => var_span,
         }
     }
 
@@ -590,8 +600,11 @@ impl UseSpans {
         match self {
             UseSpans::ClosureUse { var_span: span, .. }
             | UseSpans::PatUse(span)
-            | UseSpans::FnSelfUse { var_span: span, .. }
             | UseSpans::OtherUse(span) => span,
+            UseSpans::FnSelfUse {
+                fn_call_span, kind: FnSelfUseKind::DerefCoercion { .. }, ..
+            } => fn_call_span,
+            UseSpans::FnSelfUse { var_span, .. } => var_span,
         }
     }
 
@@ -754,7 +767,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &self,
         moved_place: PlaceRef<'tcx>, // Could also be an upvar.
         location: Location,
-    ) -> UseSpans {
+    ) -> UseSpans<'tcx> {
         use self::UseSpans::*;
 
         let stmt = match self.body[location.block].statements.get(location.statement_index) {
@@ -809,36 +822,64 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             kind: TerminatorKind::Call { fn_span, from_hir_call, .. }, ..
         }) = &self.body[location.block].terminator
         {
-            let method_did = if let Some(method_did) =
+            let (method_did, method_substs) = if let Some(info) =
                 crate::util::find_self_call(self.infcx.tcx, &self.body, target_temp, location.block)
             {
-                method_did
+                info
             } else {
                 return normal_ret;
             };
 
             let tcx = self.infcx.tcx;
-
             let parent = tcx.parent(method_did);
             let is_fn_once = parent == tcx.lang_items().fn_once_trait();
             let is_operator = !from_hir_call
                 && parent.map_or(false, |p| tcx.lang_items().group(LangItemGroup::Op).contains(&p));
+            let is_deref = !from_hir_call && tcx.is_diagnostic_item(sym::deref_method, method_did);
             let fn_call_span = *fn_span;
 
             let self_arg = tcx.fn_arg_names(method_did)[0];
 
+            debug!(
+                "terminator = {:?} from_hir_call={:?}",
+                self.body[location.block].terminator, from_hir_call
+            );
+
+            // Check for a 'special' use of 'self' -
+            // an FnOnce call, an operator (e.g. `<<`), or a
+            // deref coercion.
             let kind = if is_fn_once {
-                FnSelfUseKind::FnOnceCall
+                Some(FnSelfUseKind::FnOnceCall)
             } else if is_operator {
-                FnSelfUseKind::Operator { self_arg }
+                Some(FnSelfUseKind::Operator { self_arg })
+            } else if is_deref {
+                let deref_target =
+                    tcx.get_diagnostic_item(sym::deref_target).and_then(|deref_target| {
+                        Instance::resolve(tcx, self.param_env, deref_target, method_substs)
+                            .transpose()
+                    });
+                if let Some(Ok(instance)) = deref_target {
+                    let deref_target_ty = instance.ty(tcx, self.param_env);
+                    Some(FnSelfUseKind::DerefCoercion {
+                        deref_target: tcx.def_span(instance.def_id()),
+                        deref_target_ty,
+                    })
+                } else {
+                    None
+                }
             } else {
+                None
+            };
+
+            let kind = kind.unwrap_or_else(|| {
+                // This isn't a 'special' use of `self`
                 debug!("move_spans: method_did={:?}, fn_call_span={:?}", method_did, fn_call_span);
                 let implicit_into_iter = matches!(
                     fn_call_span.desugaring_kind(),
                     Some(DesugaringKind::ForLoop(ForLoopLoc::IntoIter))
                 );
                 FnSelfUseKind::Normal { self_arg, implicit_into_iter }
-            };
+            });
 
             return FnSelfUse {
                 var_span: stmt.source_info.span,
@@ -859,7 +900,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// and its usage of the local assigned at `location`.
     /// This is done by searching in statements succeeding `location`
     /// and originating from `maybe_closure_span`.
-    pub(super) fn borrow_spans(&self, use_span: Span, location: Location) -> UseSpans {
+    pub(super) fn borrow_spans(&self, use_span: Span, location: Location) -> UseSpans<'tcx> {
         use self::UseSpans::*;
         debug!("borrow_spans: use_span={:?} location={:?}", use_span, location);
 
@@ -963,7 +1004,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
     /// Helper to retrieve span(s) of given borrow from the current MIR
     /// representation
-    pub(super) fn retrieve_borrow_spans(&self, borrow: &BorrowData<'_>) -> UseSpans {
+    pub(super) fn retrieve_borrow_spans(&self, borrow: &BorrowData<'_>) -> UseSpans<'tcx> {
         let span = self.body.source_info(borrow.reserve_location).span;
         self.borrow_spans(span, borrow.reserve_location)
     }
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs
index 6cf1cf20b5a..e256fb55b12 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs
@@ -47,7 +47,7 @@ enum GroupedMoveError<'tcx> {
     // Everything that isn't from pattern matching.
     OtherIllegalMove {
         original_path: Place<'tcx>,
-        use_spans: UseSpans,
+        use_spans: UseSpans<'tcx>,
         kind: IllegalMoveOriginKind<'tcx>,
     },
 }
@@ -222,7 +222,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let (mut err, err_span) = {
             let (span, use_spans, original_path, kind): (
                 Span,
-                Option<UseSpans>,
+                Option<UseSpans<'tcx>>,
                 Place<'tcx>,
                 &IllegalMoveOriginKind<'_>,
             ) = match error {
@@ -291,7 +291,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         move_place: Place<'tcx>,
         deref_target_place: Place<'tcx>,
         span: Span,
-        use_spans: Option<UseSpans>,
+        use_spans: Option<UseSpans<'tcx>>,
     ) -> DiagnosticBuilder<'a> {
         // Inspect the type of the content behind the
         // borrow to provide feedback about why this
diff --git a/compiler/rustc_mir/src/borrow_check/mod.rs b/compiler/rustc_mir/src/borrow_check/mod.rs
index acd9e3dcf3f..64ad0627720 100644
--- a/compiler/rustc_mir/src/borrow_check/mod.rs
+++ b/compiler/rustc_mir/src/borrow_check/mod.rs
@@ -17,7 +17,7 @@ use rustc_middle::mir::{AggregateKind, BasicBlock, BorrowCheckResult, BorrowKind
 use rustc_middle::mir::{Field, ProjectionElem, Promoted, Rvalue, Statement, StatementKind};
 use rustc_middle::mir::{InlineAsmOperand, Terminator, TerminatorKind};
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::{self, InstanceDef, RegionVid, TyCtxt};
+use rustc_middle::ty::{self, InstanceDef, ParamEnv, RegionVid, TyCtxt};
 use rustc_session::lint::builtin::{MUTABLE_BORROW_RESERVATION_CONFLICT, UNUSED_MUT};
 use rustc_span::{Span, Symbol, DUMMY_SP};
 
@@ -287,6 +287,7 @@ fn do_mir_borrowck<'a, 'tcx>(
         if let Err((move_data, move_errors)) = move_data_results {
             let mut promoted_mbcx = MirBorrowckCtxt {
                 infcx,
+                param_env,
                 body: promoted_body,
                 mir_def_id: def.did,
                 move_data: &move_data,
@@ -320,6 +321,7 @@ fn do_mir_borrowck<'a, 'tcx>(
 
     let mut mbcx = MirBorrowckCtxt {
         infcx,
+        param_env,
         body,
         mir_def_id: def.did,
         move_data: &mdpe.move_data,
@@ -473,6 +475,7 @@ fn do_mir_borrowck<'a, 'tcx>(
 
 crate struct MirBorrowckCtxt<'cx, 'tcx> {
     crate infcx: &'cx InferCtxt<'cx, 'tcx>,
+    param_env: ParamEnv<'tcx>,
     body: &'cx Body<'tcx>,
     mir_def_id: LocalDefId,
     move_data: &'cx MoveData<'tcx>,
diff --git a/compiler/rustc_mir/src/transform/check_const_item_mutation.rs b/compiler/rustc_mir/src/transform/check_const_item_mutation.rs
index 589268e39bd..70c1aed0957 100644
--- a/compiler/rustc_mir/src/transform/check_const_item_mutation.rs
+++ b/compiler/rustc_mir/src/transform/check_const_item_mutation.rs
@@ -101,7 +101,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ConstMutationChecker<'a, 'tcx> {
                         .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");
 
-                    if let Some(method_did) = method_did {
+                    if let Some((method_did, _substs)) = method_did {
                         lint.span_note(self.tcx.def_span(method_did), "mutable reference created due to call to this method");
                     }
 
diff --git a/compiler/rustc_mir/src/util/find_self_call.rs b/compiler/rustc_mir/src/util/find_self_call.rs
index 049b5f01214..5b146eeb87c 100644
--- a/compiler/rustc_mir/src/util/find_self_call.rs
+++ b/compiler/rustc_mir/src/util/find_self_call.rs
@@ -1,30 +1,31 @@
 use rustc_middle::mir::*;
+use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::def_id::DefId;
 
 /// Checks if the specified `local` is used as the `self` prameter of a method call
 /// in the provided `BasicBlock`. If it is, then the `DefId` of the called method is
 /// returned.
-pub fn find_self_call(
-    tcx: TyCtxt<'_>,
-    body: &Body<'_>,
+pub fn find_self_call<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    body: &Body<'tcx>,
     local: Local,
     block: BasicBlock,
-) -> Option<DefId> {
+) -> Option<(DefId, SubstsRef<'tcx>)> {
     debug!("find_self_call(local={:?}): terminator={:?}", local, &body[block].terminator);
     if let Some(Terminator { kind: TerminatorKind::Call { func, args, .. }, .. }) =
         &body[block].terminator
     {
         debug!("find_self_call: func={:?}", func);
         if let Operand::Constant(box Constant { literal: ty::Const { ty, .. }, .. }) = func {
-            if let ty::FnDef(def_id, _) = *ty.kind() {
+            if let ty::FnDef(def_id, substs) = *ty.kind() {
                 if let Some(ty::AssocItem { fn_has_self_parameter: true, .. }) =
                     tcx.opt_associated_item(def_id)
                 {
                     debug!("find_self_call: args={:?}", args);
                     if let [Operand::Move(self_place) | Operand::Copy(self_place), ..] = **args {
                         if self_place.as_local() == Some(local) {
-                            return Some(def_id);
+                            return Some((def_id, substs));
                         }
                     }
                 }
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index 70c7abc2654..13e69474cfb 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -117,7 +117,14 @@ fn apply_adjustment<'a, 'tcx>(
                 },
             };
 
-            overloaded_place(cx, hir_expr, adjustment.target, Some(call), vec![expr.to_ref()])
+            overloaded_place(
+                cx,
+                hir_expr,
+                adjustment.target,
+                Some(call),
+                vec![expr.to_ref()],
+                deref.span,
+            )
         }
         Adjust::Borrow(AutoBorrow::Ref(_, m)) => {
             ExprKind::Borrow { borrow_kind: m.to_borrow_kind(), arg: expr.to_ref() }
@@ -277,7 +284,14 @@ fn make_mirror_unadjusted<'a, 'tcx>(
 
         hir::ExprKind::Index(ref lhs, ref index) => {
             if cx.typeck_results().is_method_call(expr) {
-                overloaded_place(cx, expr, expr_ty, None, vec![lhs.to_ref(), index.to_ref()])
+                overloaded_place(
+                    cx,
+                    expr,
+                    expr_ty,
+                    None,
+                    vec![lhs.to_ref(), index.to_ref()],
+                    expr.span,
+                )
             } else {
                 ExprKind::Index { lhs: lhs.to_ref(), index: index.to_ref() }
             }
@@ -285,7 +299,7 @@ fn make_mirror_unadjusted<'a, 'tcx>(
 
         hir::ExprKind::Unary(hir::UnOp::UnDeref, ref arg) => {
             if cx.typeck_results().is_method_call(expr) {
-                overloaded_place(cx, expr, expr_ty, None, vec![arg.to_ref()])
+                overloaded_place(cx, expr, expr_ty, None, vec![arg.to_ref()], expr.span)
             } else {
                 ExprKind::Deref { arg: arg.to_ref() }
             }
@@ -1025,6 +1039,7 @@ fn overloaded_place<'a, 'tcx>(
     place_ty: Ty<'tcx>,
     overloaded_callee: Option<(DefId, SubstsRef<'tcx>)>,
     args: Vec<ExprRef<'tcx>>,
+    span: Span,
 ) -> ExprKind<'tcx> {
     // For an overloaded *x or x[y] expression of type T, the method
     // call returns an &T and we must add the deref so that the types
@@ -1040,24 +1055,24 @@ fn overloaded_place<'a, 'tcx>(
     // `Deref(Mut)::Deref(_mut)` and `Index(Mut)::index(_mut)`.
     let (region, mutbl) = match *recv_ty.kind() {
         ty::Ref(region, _, mutbl) => (region, mutbl),
-        _ => span_bug!(expr.span, "overloaded_place: receiver is not a reference"),
+        _ => span_bug!(span, "overloaded_place: receiver is not a reference"),
     };
     let ref_ty = cx.tcx.mk_ref(region, ty::TypeAndMut { ty: place_ty, mutbl });
 
     // construct the complete expression `foo()` for the overloaded call,
     // which will yield the &T type
     let temp_lifetime = cx.region_scope_tree.temporary_scope(expr.hir_id.local_id);
-    let fun = method_callee(cx, expr, expr.span, overloaded_callee);
+    let fun = method_callee(cx, expr, span, overloaded_callee);
     let ref_expr = Expr {
         temp_lifetime,
         ty: ref_ty,
-        span: expr.span,
+        span,
         kind: ExprKind::Call {
             ty: fun.ty,
             fun: fun.to_ref(),
             args,
             from_hir_call: false,
-            fn_span: expr.span,
+            fn_span: span,
         },
     };
 
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 407663e5757..94f795b11ea 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -416,7 +416,9 @@ symbols! {
         deny,
         deprecated,
         deref,
+        deref_method,
         deref_mut,
+        deref_target,
         derive,
         diagnostic,
         direct,
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index d6e8b304380..f1e8330425e 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -654,6 +654,7 @@ supported_targets! {
     ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),
     ("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),
     ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
+    ("riscv32gc-unknown-linux-gnu", riscv32gc_unknown_linux_gnu),
     ("riscv64imac-unknown-none-elf", riscv64imac_unknown_none_elf),
     ("riscv64gc-unknown-none-elf", riscv64gc_unknown_none_elf),
     ("riscv64gc-unknown-linux-gnu", riscv64gc_unknown_linux_gnu),
diff --git a/compiler/rustc_target/src/spec/riscv32gc_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/riscv32gc_unknown_linux_gnu.rs
new file mode 100644
index 00000000000..28710c60175
--- /dev/null
+++ b/compiler/rustc_target/src/spec/riscv32gc_unknown_linux_gnu.rs
@@ -0,0 +1,25 @@
+use crate::spec::{CodeModel, LinkerFlavor, Target, TargetOptions, TargetResult};
+
+pub fn target() -> TargetResult {
+    Ok(Target {
+        llvm_target: "riscv32-unknown-linux-gnu".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "32".to_string(),
+        target_c_int_width: "32".to_string(),
+        target_env: "gnu".to_string(),
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S128".to_string(),
+        arch: "riscv32".to_string(),
+        target_os: "linux".to_string(),
+        target_vendor: "unknown".to_string(),
+        linker_flavor: LinkerFlavor::Gcc,
+        options: TargetOptions {
+            unsupported_abis: super::riscv_base::unsupported_abis(),
+            code_model: Some(CodeModel::Medium),
+            cpu: "generic-rv32".to_string(),
+            features: "+m,+a,+f,+d,+c".to_string(),
+            llvm_abiname: "ilp32d".to_string(),
+            max_atomic_width: Some(32),
+            ..super::linux_base::opts()
+        },
+    })
+}
diff --git a/compiler/rustc_trait_selection/src/autoderef.rs b/compiler/rustc_trait_selection/src/autoderef.rs
index 02eefe56223..b9c5123e49a 100644
--- a/compiler/rustc_trait_selection/src/autoderef.rs
+++ b/compiler/rustc_trait_selection/src/autoderef.rs
@@ -27,6 +27,7 @@ pub struct Autoderef<'a, 'tcx> {
     // Meta infos:
     infcx: &'a InferCtxt<'a, 'tcx>,
     span: Span,
+    overloaded_span: Span,
     body_id: hir::HirId,
     param_env: ty::ParamEnv<'tcx>,
 
@@ -98,10 +99,12 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
         body_id: hir::HirId,
         span: Span,
         base_ty: Ty<'tcx>,
+        overloaded_span: Span,
     ) -> Autoderef<'a, 'tcx> {
         Autoderef {
             infcx,
             span,
+            overloaded_span,
             body_id,
             param_env,
             state: AutoderefSnapshot {
@@ -190,6 +193,10 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
         self.span
     }
 
+    pub fn overloaded_span(&self) -> Span {
+        self.overloaded_span
+    }
+
     pub fn reached_recursion_limit(&self) -> bool {
         self.state.reached_recursion_limit
     }
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index 82e809d014d..90a8d9634ae 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -483,7 +483,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         };
 
         if let ty::Ref(region, base_ty, mutbl) = *real_ty.kind() {
-            let mut autoderef = Autoderef::new(self, param_env, body_id, span, base_ty);
+            let mut autoderef = Autoderef::new(self, param_env, body_id, span, base_ty, span);
             if let Some(steps) = autoderef.find_map(|(ty, steps)| {
                 // Re-add the `&`
                 let ty = self.tcx.mk_ref(region, TypeAndMut { ty, mutbl });
diff --git a/compiler/rustc_typeck/src/check/autoderef.rs b/compiler/rustc_typeck/src/check/autoderef.rs
index 17364897bde..59c366ad7d7 100644
--- a/compiler/rustc_typeck/src/check/autoderef.rs
+++ b/compiler/rustc_typeck/src/check/autoderef.rs
@@ -12,7 +12,18 @@ use std::iter;
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub fn autoderef(&'a self, span: Span, base_ty: Ty<'tcx>) -> Autoderef<'a, 'tcx> {
-        Autoderef::new(self, self.param_env, self.body_id, span, base_ty)
+        Autoderef::new(self, self.param_env, self.body_id, span, base_ty, span)
+    }
+
+    /// Like `autoderef`, but provides a custom `Span` to use for calls to
+    /// an overloaded `Deref` operator
+    pub fn autoderef_overloaded_span(
+        &'a self,
+        span: Span,
+        base_ty: Ty<'tcx>,
+        overloaded_span: Span,
+    ) -> Autoderef<'a, 'tcx> {
+        Autoderef::new(self, self.param_env, self.body_id, span, base_ty, overloaded_span)
     }
 
     pub fn try_overloaded_deref(
@@ -44,7 +55,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         |InferOk { value: method, obligations: o }| {
                             obligations.extend(o);
                             if let ty::Ref(region, _, mutbl) = *method.sig.output().kind() {
-                                Some(OverloadedDeref { region, mutbl })
+                                Some(OverloadedDeref {
+                                    region,
+                                    mutbl,
+                                    span: autoderef.overloaded_span(),
+                                })
                             } else {
                                 None
                             }
diff --git a/compiler/rustc_typeck/src/check/method/confirm.rs b/compiler/rustc_typeck/src/check/method/confirm.rs
index ae338cccf79..fd2700b85e2 100644
--- a/compiler/rustc_typeck/src/check/method/confirm.rs
+++ b/compiler/rustc_typeck/src/check/method/confirm.rs
@@ -137,7 +137,8 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
     ) -> Ty<'tcx> {
         // Commit the autoderefs by calling `autoderef` again, but this
         // time writing the results into the various typeck results.
-        let mut autoderef = self.autoderef(self.span, unadjusted_self_ty);
+        let mut autoderef =
+            self.autoderef_overloaded_span(self.span, unadjusted_self_ty, self.call_expr.span);
         let (_, n) = match autoderef.nth(pick.autoderefs) {
             Some(n) => n,
             None => {
diff --git a/compiler/rustc_typeck/src/check/method/probe.rs b/compiler/rustc_typeck/src/check/method/probe.rs
index ebe71b86c92..8a62031ec88 100644
--- a/compiler/rustc_typeck/src/check/method/probe.rs
+++ b/compiler/rustc_typeck/src/check/method/probe.rs
@@ -446,9 +446,10 @@ fn method_autoderef_steps<'tcx>(
     tcx.infer_ctxt().enter_with_canonical(DUMMY_SP, &goal, |ref infcx, goal, inference_vars| {
         let ParamEnvAnd { param_env, value: self_ty } = goal;
 
-        let mut autoderef = Autoderef::new(infcx, param_env, hir::CRATE_HIR_ID, DUMMY_SP, self_ty)
-            .include_raw_pointers()
-            .silence_errors();
+        let mut autoderef =
+            Autoderef::new(infcx, param_env, hir::CRATE_HIR_ID, DUMMY_SP, self_ty, DUMMY_SP)
+                .include_raw_pointers()
+                .silence_errors();
         let mut reached_raw_pointer = false;
         let mut steps: Vec<_> = autoderef
             .by_ref()
diff --git a/compiler/rustc_typeck/src/check/place_op.rs b/compiler/rustc_typeck/src/check/place_op.rs
index aed2af20e52..502cb562385 100644
--- a/compiler/rustc_typeck/src/check/place_op.rs
+++ b/compiler/rustc_typeck/src/check/place_op.rs
@@ -242,7 +242,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         ) {
                             let method = self.register_infer_ok_obligations(ok);
                             if let ty::Ref(region, _, mutbl) = *method.sig.output().kind() {
-                                *deref = OverloadedDeref { region, mutbl };
+                                *deref = OverloadedDeref { region, mutbl, span: deref.span };
                             }
                             // If this is a union field, also throw an error for `DerefMut` of `ManuallyDrop` (see RFC 2514).
                             // This helps avoid accidental drops.
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 590639d9834..03737e1ef1f 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -15,6 +15,7 @@
 #![feature(slice_ptr_get)]
 #![feature(split_inclusive)]
 #![feature(binary_heap_retain)]
+#![feature(deque_range)]
 #![feature(inplace_iteration)]
 #![feature(iter_map_while)]
 
diff --git a/library/alloc/tests/string.rs b/library/alloc/tests/string.rs
index f7f78046d08..4e604354122 100644
--- a/library/alloc/tests/string.rs
+++ b/library/alloc/tests/string.rs
@@ -1,6 +1,7 @@
 use std::borrow::Cow;
 use std::collections::TryReserveError::*;
 use std::mem::size_of;
+use std::ops::Bound::*;
 
 pub trait IntoCow<'a, B: ?Sized>
 where
@@ -271,8 +272,8 @@ fn test_split_off_past_end() {
 #[test]
 #[should_panic]
 fn test_split_off_mid_char() {
-    let mut orig = String::from("山");
-    let _ = orig.split_off(1);
+    let mut shan = String::from("山");
+    let _broken_mountain = shan.split_off(1);
 }
 
 #[test]
@@ -468,6 +469,20 @@ fn test_drain() {
 }
 
 #[test]
+#[should_panic]
+fn test_drain_start_overflow() {
+    let mut s = String::from("abc");
+    s.drain((Excluded(usize::MAX), Included(0)));
+}
+
+#[test]
+#[should_panic]
+fn test_drain_end_overflow() {
+    let mut s = String::from("abc");
+    s.drain((Included(0), Included(usize::MAX)));
+}
+
+#[test]
 fn test_replace_range() {
     let mut s = "Hello, world!".to_owned();
     s.replace_range(7..12, "世界");
@@ -505,6 +520,20 @@ fn test_replace_range_inclusive_out_of_bounds() {
 }
 
 #[test]
+#[should_panic]
+fn test_replace_range_start_overflow() {
+    let mut s = String::from("123");
+    s.replace_range((Excluded(usize::MAX), Included(0)), "");
+}
+
+#[test]
+#[should_panic]
+fn test_replace_range_end_overflow() {
+    let mut s = String::from("456");
+    s.replace_range((Included(0), Included(usize::MAX)), "");
+}
+
+#[test]
 fn test_replace_range_empty() {
     let mut s = String::from("12345");
     s.replace_range(1..2, "");
diff --git a/library/alloc/tests/vec.rs b/library/alloc/tests/vec.rs
index 608a3c9bdf7..563dd7ab645 100644
--- a/library/alloc/tests/vec.rs
+++ b/library/alloc/tests/vec.rs
@@ -3,6 +3,7 @@ use std::collections::TryReserveError::*;
 use std::fmt::Debug;
 use std::iter::InPlaceIterable;
 use std::mem::size_of;
+use std::ops::Bound::*;
 use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::rc::Rc;
 use std::vec::{Drain, IntoIter};
@@ -647,12 +648,36 @@ fn test_drain_max_vec_size() {
 
 #[test]
 #[should_panic]
+fn test_drain_index_overflow() {
+    let mut v = Vec::<()>::with_capacity(usize::MAX);
+    unsafe {
+        v.set_len(usize::MAX);
+    }
+    v.drain(0..=usize::MAX);
+}
+
+#[test]
+#[should_panic]
 fn test_drain_inclusive_out_of_bounds() {
     let mut v = vec![1, 2, 3, 4, 5];
     v.drain(5..=5);
 }
 
 #[test]
+#[should_panic]
+fn test_drain_start_overflow() {
+    let mut v = vec![1, 2, 3];
+    v.drain((Excluded(usize::MAX), Included(0)));
+}
+
+#[test]
+#[should_panic]
+fn test_drain_end_overflow() {
+    let mut v = vec![1, 2, 3];
+    v.drain((Included(0), Included(usize::MAX)));
+}
+
+#[test]
 fn test_drain_leak() {
     static mut DROPS: i32 = 0;
 
diff --git a/library/alloc/tests/vec_deque.rs b/library/alloc/tests/vec_deque.rs
index 762dc4be44d..46d8a3c4cb4 100644
--- a/library/alloc/tests/vec_deque.rs
+++ b/library/alloc/tests/vec_deque.rs
@@ -2,6 +2,7 @@ use std::collections::TryReserveError::*;
 use std::collections::{vec_deque::Drain, VecDeque};
 use std::fmt::Debug;
 use std::mem::size_of;
+use std::ops::Bound::*;
 use std::panic::{catch_unwind, AssertUnwindSafe};
 
 use crate::hash;
@@ -115,6 +116,20 @@ fn test_index_out_of_bounds() {
     deq[3];
 }
 
+#[test]
+#[should_panic]
+fn test_range_start_overflow() {
+    let deq = VecDeque::from(vec![1, 2, 3]);
+    deq.range((Included(0), Included(usize::MAX)));
+}
+
+#[test]
+#[should_panic]
+fn test_range_end_overflow() {
+    let deq = VecDeque::from(vec![1, 2, 3]);
+    deq.range((Excluded(usize::MAX), Included(0)));
+}
+
 #[derive(Clone, PartialEq, Debug)]
 enum Taggy {
     One(i32),
diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs
index 3953c73319f..dde442aa7b5 100644
--- a/library/core/src/cmp.rs
+++ b/library/core/src/cmp.rs
@@ -356,8 +356,9 @@ impl Ordering {
     /// ```
     #[inline]
     #[must_use]
+    #[rustc_const_stable(feature = "const_ordering", since = "1.48.0")]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn reverse(self) -> Ordering {
+    pub const fn reverse(self) -> Ordering {
         match self {
             Less => Greater,
             Equal => Equal,
@@ -394,8 +395,9 @@ impl Ordering {
     /// ```
     #[inline]
     #[must_use]
+    #[rustc_const_stable(feature = "const_ordering", since = "1.48.0")]
     #[stable(feature = "ordering_chaining", since = "1.17.0")]
-    pub fn then(self, other: Ordering) -> Ordering {
+    pub const fn then(self, other: Ordering) -> Ordering {
         match self {
             Equal => other,
             _ => self,
diff --git a/library/core/src/ops/deref.rs b/library/core/src/ops/deref.rs
index d6c097eee17..245152e5490 100644
--- a/library/core/src/ops/deref.rs
+++ b/library/core/src/ops/deref.rs
@@ -63,11 +63,13 @@
 pub trait Deref {
     /// The resulting type after dereferencing.
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_diagnostic_item = "deref_target"]
     type Target: ?Sized;
 
     /// Dereferences the value.
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_diagnostic_item = "deref_method"]
     fn deref(&self) -> &Self::Target;
 }
 
diff --git a/library/core/tests/cmp.rs b/library/core/tests/cmp.rs
index 4086917780f..835289daf71 100644
--- a/library/core/tests/cmp.rs
+++ b/library/core/tests/cmp.rs
@@ -1,4 +1,7 @@
-use core::cmp::{self, Ordering::*};
+use core::cmp::{
+    self,
+    Ordering::{self, *},
+};
 
 #[test]
 fn test_int_totalord() {
@@ -116,3 +119,16 @@ fn test_user_defined_eq() {
     assert!(SketchyNum { num: 37 } == SketchyNum { num: 34 });
     assert!(SketchyNum { num: 25 } != SketchyNum { num: 57 });
 }
+
+#[test]
+fn ordering_const() {
+    // test that the methods of `Ordering` are usable in a const context
+
+    const ORDERING: Ordering = Greater;
+
+    const REVERSE: Ordering = ORDERING.reverse();
+    assert_eq!(REVERSE, Less);
+
+    const THEN: Ordering = Equal.then(ORDERING);
+    assert_eq!(THEN, Greater);
+}
diff --git a/library/std/src/process.rs b/library/std/src/process.rs
index d1960a049d9..00e2dbc9c1d 100644
--- a/library/std/src/process.rs
+++ b/library/std/src/process.rs
@@ -95,6 +95,7 @@
 //! [`Read`]: io::Read
 
 #![stable(feature = "process", since = "1.0.0")]
+#![deny(unsafe_op_in_unsafe_fn)]
 
 #[cfg(all(test, not(any(target_os = "cloudabi", target_os = "emscripten", target_env = "sgx"))))]
 mod tests;
@@ -321,7 +322,8 @@ impl Read for ChildStdout {
 
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
-        Initializer::nop()
+        // SAFETY: Read is guaranteed to work on uninitialized memory
+        unsafe { Initializer::nop() }
     }
 }
 
@@ -381,7 +383,8 @@ impl Read for ChildStderr {
 
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
-        Initializer::nop()
+        // SAFETY: Read is guaranteed to work on uninitialized memory
+        unsafe { Initializer::nop() }
     }
 }
 
diff --git a/library/std/src/sys/sgx/fs.rs b/library/std/src/sys/sgx/fs.rs
deleted file mode 100644
index ecb5b51cccd..00000000000
--- a/library/std/src/sys/sgx/fs.rs
+++ /dev/null
@@ -1,308 +0,0 @@
-use crate::ffi::OsString;
-use crate::fmt;
-use crate::hash::{Hash, Hasher};
-use crate::io::{self, IoSlice, IoSliceMut, SeekFrom};
-use crate::path::{Path, PathBuf};
-use crate::sys::time::SystemTime;
-use crate::sys::{unsupported, Void};
-
-pub struct File(Void);
-
-pub struct FileAttr(Void);
-
-pub struct ReadDir(Void);
-
-pub struct DirEntry(Void);
-
-#[derive(Clone, Debug)]
-pub struct OpenOptions {}
-
-pub struct FilePermissions(Void);
-
-pub struct FileType(Void);
-
-#[derive(Debug)]
-pub struct DirBuilder {}
-
-impl FileAttr {
-    pub fn size(&self) -> u64 {
-        match self.0 {}
-    }
-
-    pub fn perm(&self) -> FilePermissions {
-        match self.0 {}
-    }
-
-    pub fn file_type(&self) -> FileType {
-        match self.0 {}
-    }
-
-    pub fn modified(&self) -> io::Result<SystemTime> {
-        match self.0 {}
-    }
-
-    pub fn accessed(&self) -> io::Result<SystemTime> {
-        match self.0 {}
-    }
-
-    pub fn created(&self) -> io::Result<SystemTime> {
-        match self.0 {}
-    }
-}
-
-impl Clone for FileAttr {
-    fn clone(&self) -> FileAttr {
-        match self.0 {}
-    }
-}
-
-impl FilePermissions {
-    pub fn readonly(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn set_readonly(&mut self, _readonly: bool) {
-        match self.0 {}
-    }
-}
-
-impl Clone for FilePermissions {
-    fn clone(&self) -> FilePermissions {
-        match self.0 {}
-    }
-}
-
-impl PartialEq for FilePermissions {
-    fn eq(&self, _other: &FilePermissions) -> bool {
-        match self.0 {}
-    }
-}
-
-impl Eq for FilePermissions {}
-
-impl fmt::Debug for FilePermissions {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0 {}
-    }
-}
-
-impl FileType {
-    pub fn is_dir(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn is_file(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn is_symlink(&self) -> bool {
-        match self.0 {}
-    }
-}
-
-impl Clone for FileType {
-    fn clone(&self) -> FileType {
-        match self.0 {}
-    }
-}
-
-impl Copy for FileType {}
-
-impl PartialEq for FileType {
-    fn eq(&self, _other: &FileType) -> bool {
-        match self.0 {}
-    }
-}
-
-impl Eq for FileType {}
-
-impl Hash for FileType {
-    fn hash<H: Hasher>(&self, _h: &mut H) {
-        match self.0 {}
-    }
-}
-
-impl fmt::Debug for FileType {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0 {}
-    }
-}
-
-impl fmt::Debug for ReadDir {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0 {}
-    }
-}
-
-impl Iterator for ReadDir {
-    type Item = io::Result<DirEntry>;
-
-    fn next(&mut self) -> Option<io::Result<DirEntry>> {
-        match self.0 {}
-    }
-}
-
-impl DirEntry {
-    pub fn path(&self) -> PathBuf {
-        match self.0 {}
-    }
-
-    pub fn file_name(&self) -> OsString {
-        match self.0 {}
-    }
-
-    pub fn metadata(&self) -> io::Result<FileAttr> {
-        match self.0 {}
-    }
-
-    pub fn file_type(&self) -> io::Result<FileType> {
-        match self.0 {}
-    }
-}
-
-impl OpenOptions {
-    pub fn new() -> OpenOptions {
-        OpenOptions {}
-    }
-
-    pub fn read(&mut self, _read: bool) {}
-    pub fn write(&mut self, _write: bool) {}
-    pub fn append(&mut self, _append: bool) {}
-    pub fn truncate(&mut self, _truncate: bool) {}
-    pub fn create(&mut self, _create: bool) {}
-    pub fn create_new(&mut self, _create_new: bool) {}
-}
-
-impl File {
-    pub fn open(_path: &Path, _opts: &OpenOptions) -> io::Result<File> {
-        unsupported()
-    }
-
-    pub fn file_attr(&self) -> io::Result<FileAttr> {
-        match self.0 {}
-    }
-
-    pub fn fsync(&self) -> io::Result<()> {
-        match self.0 {}
-    }
-
-    pub fn datasync(&self) -> io::Result<()> {
-        match self.0 {}
-    }
-
-    pub fn truncate(&self, _size: u64) -> io::Result<()> {
-        match self.0 {}
-    }
-
-    pub fn read(&self, _buf: &mut [u8]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn read_vectored(&self, _bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn is_read_vectored(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn write_vectored(&self, _bufs: &[IoSlice<'_>]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn is_write_vectored(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn flush(&self) -> io::Result<()> {
-        match self.0 {}
-    }
-
-    pub fn seek(&self, _pos: SeekFrom) -> io::Result<u64> {
-        match self.0 {}
-    }
-
-    pub fn duplicate(&self) -> io::Result<File> {
-        match self.0 {}
-    }
-
-    pub fn set_permissions(&self, _perm: FilePermissions) -> io::Result<()> {
-        match self.0 {}
-    }
-
-    pub fn diverge(&self) -> ! {
-        match self.0 {}
-    }
-}
-
-impl DirBuilder {
-    pub fn new() -> DirBuilder {
-        DirBuilder {}
-    }
-
-    pub fn mkdir(&self, _p: &Path) -> io::Result<()> {
-        unsupported()
-    }
-}
-
-impl fmt::Debug for File {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0 {}
-    }
-}
-
-pub fn readdir(_p: &Path) -> io::Result<ReadDir> {
-    unsupported()
-}
-
-pub fn unlink(_p: &Path) -> io::Result<()> {
-    unsupported()
-}
-
-pub fn rename(_old: &Path, _new: &Path) -> io::Result<()> {
-    unsupported()
-}
-
-pub fn set_perm(_p: &Path, perm: FilePermissions) -> io::Result<()> {
-    match perm.0 {}
-}
-
-pub fn rmdir(_p: &Path) -> io::Result<()> {
-    unsupported()
-}
-
-pub fn remove_dir_all(_path: &Path) -> io::Result<()> {
-    unsupported()
-}
-
-pub fn readlink(_p: &Path) -> io::Result<PathBuf> {
-    unsupported()
-}
-
-pub fn symlink(_src: &Path, _dst: &Path) -> io::Result<()> {
-    unsupported()
-}
-
-pub fn link(_src: &Path, _dst: &Path) -> io::Result<()> {
-    unsupported()
-}
-
-pub fn stat(_p: &Path) -> io::Result<FileAttr> {
-    unsupported()
-}
-
-pub fn lstat(_p: &Path) -> io::Result<FileAttr> {
-    unsupported()
-}
-
-pub fn canonicalize(_p: &Path) -> io::Result<PathBuf> {
-    unsupported()
-}
-
-pub fn copy(_from: &Path, _to: &Path) -> io::Result<u64> {
-    unsupported()
-}
diff --git a/library/std/src/sys/sgx/io.rs b/library/std/src/sys/sgx/io.rs
deleted file mode 100644
index d5f475b4310..00000000000
--- a/library/std/src/sys/sgx/io.rs
+++ /dev/null
@@ -1,47 +0,0 @@
-use crate::mem;
-
-#[derive(Copy, Clone)]
-pub struct IoSlice<'a>(&'a [u8]);
-
-impl<'a> IoSlice<'a> {
-    #[inline]
-    pub fn new(buf: &'a [u8]) -> IoSlice<'a> {
-        IoSlice(buf)
-    }
-
-    #[inline]
-    pub fn advance(&mut self, n: usize) {
-        self.0 = &self.0[n..]
-    }
-
-    #[inline]
-    pub fn as_slice(&self) -> &[u8] {
-        self.0
-    }
-}
-
-pub struct IoSliceMut<'a>(&'a mut [u8]);
-
-impl<'a> IoSliceMut<'a> {
-    #[inline]
-    pub fn new(buf: &'a mut [u8]) -> IoSliceMut<'a> {
-        IoSliceMut(buf)
-    }
-
-    #[inline]
-    pub fn advance(&mut self, n: usize) {
-        let slice = mem::replace(&mut self.0, &mut []);
-        let (_, remaining) = slice.split_at_mut(n);
-        self.0 = remaining;
-    }
-
-    #[inline]
-    pub fn as_slice(&self) -> &[u8] {
-        self.0
-    }
-
-    #[inline]
-    pub fn as_mut_slice(&mut self) -> &mut [u8] {
-        self.0
-    }
-}
diff --git a/library/std/src/sys/sgx/mod.rs b/library/std/src/sys/sgx/mod.rs
index 1d32eb25424..1abd91e75e8 100644
--- a/library/std/src/sys/sgx/mod.rs
+++ b/library/std/src/sys/sgx/mod.rs
@@ -17,14 +17,18 @@ pub mod condvar;
 pub mod env;
 pub mod ext;
 pub mod fd;
+#[path = "../unsupported/fs.rs"]
 pub mod fs;
+#[path = "../unsupported/io.rs"]
 pub mod io;
 pub mod memchr;
 pub mod mutex;
 pub mod net;
 pub mod os;
 pub mod path;
+#[path = "../unsupported/pipe.rs"]
 pub mod pipe;
+#[path = "../unsupported/process.rs"]
 pub mod process;
 pub mod rwlock;
 pub mod stack_overflow;
diff --git a/library/std/src/sys/sgx/pipe.rs b/library/std/src/sys/sgx/pipe.rs
deleted file mode 100644
index 10d0925823e..00000000000
--- a/library/std/src/sys/sgx/pipe.rs
+++ /dev/null
@@ -1,38 +0,0 @@
-use crate::io::{self, IoSlice, IoSliceMut};
-use crate::sys::Void;
-
-pub struct AnonPipe(Void);
-
-impl AnonPipe {
-    pub fn read(&self, _buf: &mut [u8]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn read_vectored(&self, _bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn is_read_vectored(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn write_vectored(&self, _bufs: &[IoSlice<'_>]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn is_write_vectored(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn diverge(&self) -> ! {
-        match self.0 {}
-    }
-}
-
-pub fn read2(p1: AnonPipe, _v1: &mut Vec<u8>, _p2: AnonPipe, _v2: &mut Vec<u8>) -> io::Result<()> {
-    match p1.0 {}
-}
diff --git a/library/std/src/sys/sgx/process.rs b/library/std/src/sys/sgx/process.rs
deleted file mode 100644
index 4702e5c5492..00000000000
--- a/library/std/src/sys/sgx/process.rs
+++ /dev/null
@@ -1,149 +0,0 @@
-use crate::ffi::OsStr;
-use crate::fmt;
-use crate::io;
-use crate::sys::fs::File;
-use crate::sys::pipe::AnonPipe;
-use crate::sys::{unsupported, Void};
-use crate::sys_common::process::CommandEnv;
-
-pub use crate::ffi::OsString as EnvKey;
-
-////////////////////////////////////////////////////////////////////////////////
-// Command
-////////////////////////////////////////////////////////////////////////////////
-
-pub struct Command {
-    env: CommandEnv,
-}
-
-// passed back to std::process with the pipes connected to the child, if any
-// were requested
-pub struct StdioPipes {
-    pub stdin: Option<AnonPipe>,
-    pub stdout: Option<AnonPipe>,
-    pub stderr: Option<AnonPipe>,
-}
-
-pub enum Stdio {
-    Inherit,
-    Null,
-    MakePipe,
-}
-
-impl Command {
-    pub fn new(_program: &OsStr) -> Command {
-        Command { env: Default::default() }
-    }
-
-    pub fn arg(&mut self, _arg: &OsStr) {}
-
-    pub fn env_mut(&mut self) -> &mut CommandEnv {
-        &mut self.env
-    }
-
-    pub fn cwd(&mut self, _dir: &OsStr) {}
-
-    pub fn stdin(&mut self, _stdin: Stdio) {}
-
-    pub fn stdout(&mut self, _stdout: Stdio) {}
-
-    pub fn stderr(&mut self, _stderr: Stdio) {}
-
-    pub fn spawn(
-        &mut self,
-        _default: Stdio,
-        _needs_stdin: bool,
-    ) -> io::Result<(Process, StdioPipes)> {
-        unsupported()
-    }
-}
-
-impl From<AnonPipe> for Stdio {
-    fn from(pipe: AnonPipe) -> Stdio {
-        pipe.diverge()
-    }
-}
-
-impl From<File> for Stdio {
-    fn from(file: File) -> Stdio {
-        file.diverge()
-    }
-}
-
-impl fmt::Debug for Command {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Ok(())
-    }
-}
-
-pub struct ExitStatus(Void);
-
-impl ExitStatus {
-    pub fn success(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn code(&self) -> Option<i32> {
-        match self.0 {}
-    }
-}
-
-impl Clone for ExitStatus {
-    fn clone(&self) -> ExitStatus {
-        match self.0 {}
-    }
-}
-
-impl Copy for ExitStatus {}
-
-impl PartialEq for ExitStatus {
-    fn eq(&self, _other: &ExitStatus) -> bool {
-        match self.0 {}
-    }
-}
-
-impl Eq for ExitStatus {}
-
-impl fmt::Debug for ExitStatus {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0 {}
-    }
-}
-
-impl fmt::Display for ExitStatus {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0 {}
-    }
-}
-
-#[derive(PartialEq, Eq, Clone, Copy, Debug)]
-pub struct ExitCode(bool);
-
-impl ExitCode {
-    pub const SUCCESS: ExitCode = ExitCode(false);
-    pub const FAILURE: ExitCode = ExitCode(true);
-
-    pub fn as_i32(&self) -> i32 {
-        self.0 as i32
-    }
-}
-
-pub struct Process(Void);
-
-impl Process {
-    pub fn id(&self) -> u32 {
-        match self.0 {}
-    }
-
-    pub fn kill(&mut self) -> io::Result<()> {
-        match self.0 {}
-    }
-
-    pub fn wait(&mut self) -> io::Result<ExitStatus> {
-        match self.0 {}
-    }
-
-    pub fn try_wait(&mut self) -> io::Result<Option<ExitStatus>> {
-        match self.0 {}
-    }
-}
diff --git a/library/std/src/sys/unix/alloc.rs b/library/std/src/sys/unix/alloc.rs
index 8e193935460..964abe8b8c9 100644
--- a/library/std/src/sys/unix/alloc.rs
+++ b/library/std/src/sys/unix/alloc.rs
@@ -52,46 +52,48 @@ unsafe impl GlobalAlloc for System {
     }
 }
 
-#[cfg(any(
-    target_os = "android",
-    target_os = "illumos",
-    target_os = "redox",
-    target_os = "solaris"
-))]
-#[inline]
-unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
-    // On android we currently target API level 9 which unfortunately
-    // doesn't have the `posix_memalign` API used below. Instead we use
-    // `memalign`, but this unfortunately has the property on some systems
-    // where the memory returned cannot be deallocated by `free`!
-    //
-    // Upon closer inspection, however, this appears to work just fine with
-    // Android, so for this platform we should be fine to call `memalign`
-    // (which is present in API level 9). Some helpful references could
-    // possibly be chromium using memalign [1], attempts at documenting that
-    // memalign + free is ok [2] [3], or the current source of chromium
-    // which still uses memalign on android [4].
-    //
-    // [1]: https://codereview.chromium.org/10796020/
-    // [2]: https://code.google.com/p/android/issues/detail?id=35391
-    // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
-    // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
-    //                                       /memory/aligned_memory.cc
-    libc::memalign(layout.align(), layout.size()) as *mut u8
-}
-
-#[cfg(not(any(
-    target_os = "android",
-    target_os = "illumos",
-    target_os = "redox",
-    target_os = "solaris"
-)))]
-#[inline]
-unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
-    let mut out = ptr::null_mut();
-    // posix_memalign requires that the alignment be a multiple of `sizeof(void*)`.
-    // Since these are all powers of 2, we can just use max.
-    let align = layout.align().max(crate::mem::size_of::<usize>());
-    let ret = libc::posix_memalign(&mut out, align, layout.size());
-    if ret != 0 { ptr::null_mut() } else { out as *mut u8 }
+cfg_if::cfg_if! {
+    if #[cfg(any(
+        target_os = "android",
+        target_os = "illumos",
+        target_os = "redox",
+        target_os = "solaris"
+    ))] {
+        #[inline]
+        unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
+            // On android we currently target API level 9 which unfortunately
+            // doesn't have the `posix_memalign` API used below. Instead we use
+            // `memalign`, but this unfortunately has the property on some systems
+            // where the memory returned cannot be deallocated by `free`!
+            //
+            // Upon closer inspection, however, this appears to work just fine with
+            // Android, so for this platform we should be fine to call `memalign`
+            // (which is present in API level 9). Some helpful references could
+            // possibly be chromium using memalign [1], attempts at documenting that
+            // memalign + free is ok [2] [3], or the current source of chromium
+            // which still uses memalign on android [4].
+            //
+            // [1]: https://codereview.chromium.org/10796020/
+            // [2]: https://code.google.com/p/android/issues/detail?id=35391
+            // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
+            // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
+            //                                       /memory/aligned_memory.cc
+            libc::memalign(layout.align(), layout.size()) as *mut u8
+        }
+    } else if #[cfg(target_os = "wasi")] {
+        #[inline]
+        unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
+            libc::aligned_alloc(layout.align(), layout.size()) as *mut u8
+        }
+    } else {
+        #[inline]
+        unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
+            let mut out = ptr::null_mut();
+            // posix_memalign requires that the alignment be a multiple of `sizeof(void*)`.
+            // Since these are all powers of 2, we can just use max.
+            let align = layout.align().max(crate::mem::size_of::<usize>());
+            let ret = libc::posix_memalign(&mut out, align, layout.size());
+            if ret != 0 { ptr::null_mut() } else { out as *mut u8 }
+        }
+    }
 }
diff --git a/library/std/src/sys/unsupported/fs.rs b/library/std/src/sys/unsupported/fs.rs
index ecb5b51cccd..faa53b6a744 100644
--- a/library/std/src/sys/unsupported/fs.rs
+++ b/library/std/src/sys/unsupported/fs.rs
@@ -233,10 +233,6 @@ impl File {
     pub fn set_permissions(&self, _perm: FilePermissions) -> io::Result<()> {
         match self.0 {}
     }
-
-    pub fn diverge(&self) -> ! {
-        match self.0 {}
-    }
 }
 
 impl DirBuilder {
diff --git a/library/std/src/sys/unsupported/mod.rs b/library/std/src/sys/unsupported/mod.rs
index 87f655eecd5..8ba870c5dbc 100644
--- a/library/std/src/sys/unsupported/mod.rs
+++ b/library/std/src/sys/unsupported/mod.rs
@@ -8,6 +8,7 @@ pub mod io;
 pub mod mutex;
 pub mod net;
 pub mod os;
+#[path = "../unix/path.rs"]
 pub mod path;
 pub mod pipe;
 pub mod process;
diff --git a/library/std/src/sys/unsupported/path.rs b/library/std/src/sys/unsupported/path.rs
deleted file mode 100644
index 840a7ae0426..00000000000
--- a/library/std/src/sys/unsupported/path.rs
+++ /dev/null
@@ -1,19 +0,0 @@
-use crate::ffi::OsStr;
-use crate::path::Prefix;
-
-#[inline]
-pub fn is_sep_byte(b: u8) -> bool {
-    b == b'/'
-}
-
-#[inline]
-pub fn is_verbatim_sep(b: u8) -> bool {
-    b == b'/'
-}
-
-pub fn parse_prefix(_: &OsStr) -> Option<Prefix<'_>> {
-    None
-}
-
-pub const MAIN_SEP_STR: &str = "/";
-pub const MAIN_SEP: char = '/';
diff --git a/library/std/src/sys/unsupported/process.rs b/library/std/src/sys/unsupported/process.rs
index 4702e5c5492..7156c9ab92f 100644
--- a/library/std/src/sys/unsupported/process.rs
+++ b/library/std/src/sys/unsupported/process.rs
@@ -65,8 +65,8 @@ impl From<AnonPipe> for Stdio {
 }
 
 impl From<File> for Stdio {
-    fn from(file: File) -> Stdio {
-        file.diverge()
+    fn from(_file: File) -> Stdio {
+        panic!("unsupported")
     }
 }
 
diff --git a/library/std/src/sys/wasi/alloc.rs b/library/std/src/sys/wasi/alloc.rs
deleted file mode 100644
index 4d0afe27bb8..00000000000
--- a/library/std/src/sys/wasi/alloc.rs
+++ /dev/null
@@ -1,69 +0,0 @@
-#![deny(unsafe_op_in_unsafe_fn)]
-
-use crate::alloc::{GlobalAlloc, Layout, System};
-use crate::ptr;
-use crate::sys_common::alloc::{realloc_fallback, MIN_ALIGN};
-
-// SAFETY: All methods implemented follow the contract rules defined
-// in `GlobalAlloc`.
-#[stable(feature = "alloc_system_type", since = "1.28.0")]
-unsafe impl GlobalAlloc for System {
-    #[inline]
-    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
-            // SAFETY: `libc::malloc` is guaranteed to be safe, it will allocate
-            // `layout.size()` bytes of memory and return a pointer to it
-            unsafe { libc::malloc(layout.size()) as *mut u8 }
-        } else {
-            // SAFETY: `libc::aligned_alloc` is guaranteed to be safe if
-            // `layout.size()` is a multiple of `layout.align()`. This
-            // constraint can be satisfied if `pad_to_align` is called,
-            // which creates a layout by rounding the size of this layout up
-            // to a multiple of the layout's alignment
-            let aligned_layout = layout.pad_to_align();
-            unsafe { libc::aligned_alloc(aligned_layout.align(), aligned_layout.size()) as *mut u8 }
-        }
-    }
-
-    #[inline]
-    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
-        if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
-            // SAFETY: `libc::calloc` is safe as long that `layout.size() * 1`
-            // would not result in integer overflow which cannot happen,
-            // multiplying by one never overflows
-            unsafe { libc::calloc(layout.size(), 1) as *mut u8 }
-        } else {
-            // SAFETY: The safety contract for `alloc` must be upheld by the caller
-            let ptr = unsafe { self.alloc(layout.clone()) };
-            if !ptr.is_null() {
-                // SAFETY: in the case of the `ptr` being not null
-                // it will be properly aligned and a valid ptr
-                // which satisfies `ptr::write_bytes` safety constrains
-                unsafe { ptr::write_bytes(ptr, 0, layout.size()) };
-            }
-            ptr
-        }
-    }
-
-    #[inline]
-    unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
-        // SAFETY: `libc::free` is guaranteed to be safe if `ptr` is allocated
-        // by this allocator or if `ptr` is NULL
-        unsafe { libc::free(ptr as *mut libc::c_void) }
-    }
-
-    #[inline]
-    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
-        if layout.align() <= MIN_ALIGN && layout.align() <= new_size {
-            // SAFETY: `libc::realloc` is safe if `ptr` is allocated by this
-            // allocator or NULL
-            // - If `new_size` is 0 and `ptr` is not NULL, it will act as `libc::free`
-            // - If `new_size` is not 0 and `ptr` is NULL, it will act as `libc::malloc`
-            // - Else, it will resize the block accordingly
-            unsafe { libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8 }
-        } else {
-            // SAFETY: The safety contract for `realloc_fallback` must be upheld by the caller
-            unsafe { realloc_fallback(self, ptr, layout, new_size) }
-        }
-    }
-}
diff --git a/library/std/src/sys/wasi/mod.rs b/library/std/src/sys/wasi/mod.rs
index 2704ff484f9..a7a4407ac38 100644
--- a/library/std/src/sys/wasi/mod.rs
+++ b/library/std/src/sys/wasi/mod.rs
@@ -17,6 +17,7 @@
 use crate::io as std_io;
 use crate::mem;
 
+#[path = "../unix/alloc.rs"]
 pub mod alloc;
 pub mod args;
 #[path = "../unsupported/cmath.rs"]
@@ -33,8 +34,11 @@ pub mod net;
 pub mod os;
 pub use crate::sys_common::os_str_bytes as os_str;
 pub mod ext;
+#[path = "../unix/path.rs"]
 pub mod path;
+#[path = "../unsupported/pipe.rs"]
 pub mod pipe;
+#[path = "../unsupported/process.rs"]
 pub mod process;
 #[path = "../unsupported/rwlock.rs"]
 pub mod rwlock;
diff --git a/library/std/src/sys/wasi/path.rs b/library/std/src/sys/wasi/path.rs
deleted file mode 100644
index 840a7ae0426..00000000000
--- a/library/std/src/sys/wasi/path.rs
+++ /dev/null
@@ -1,19 +0,0 @@
-use crate::ffi::OsStr;
-use crate::path::Prefix;
-
-#[inline]
-pub fn is_sep_byte(b: u8) -> bool {
-    b == b'/'
-}
-
-#[inline]
-pub fn is_verbatim_sep(b: u8) -> bool {
-    b == b'/'
-}
-
-pub fn parse_prefix(_: &OsStr) -> Option<Prefix<'_>> {
-    None
-}
-
-pub const MAIN_SEP_STR: &str = "/";
-pub const MAIN_SEP: char = '/';
diff --git a/library/std/src/sys/wasi/pipe.rs b/library/std/src/sys/wasi/pipe.rs
deleted file mode 100644
index 180fc114d86..00000000000
--- a/library/std/src/sys/wasi/pipe.rs
+++ /dev/null
@@ -1,40 +0,0 @@
-#![deny(unsafe_op_in_unsafe_fn)]
-
-use crate::io::{self, IoSlice, IoSliceMut};
-use crate::sys::Void;
-
-pub struct AnonPipe(Void);
-
-impl AnonPipe {
-    pub fn read(&self, _buf: &mut [u8]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn read_vectored(&self, _bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn is_read_vectored(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn write_vectored(&self, _bufs: &[IoSlice<'_>]) -> io::Result<usize> {
-        match self.0 {}
-    }
-
-    pub fn is_write_vectored(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn diverge(&self) -> ! {
-        match self.0 {}
-    }
-}
-
-pub fn read2(p1: AnonPipe, _v1: &mut Vec<u8>, _p2: AnonPipe, _v2: &mut Vec<u8>) -> io::Result<()> {
-    match p1.0 {}
-}
diff --git a/library/std/src/sys/wasi/process.rs b/library/std/src/sys/wasi/process.rs
deleted file mode 100644
index c69d6376b01..00000000000
--- a/library/std/src/sys/wasi/process.rs
+++ /dev/null
@@ -1,151 +0,0 @@
-#![deny(unsafe_op_in_unsafe_fn)]
-
-use crate::ffi::OsStr;
-use crate::fmt;
-use crate::io;
-use crate::sys::fs::File;
-use crate::sys::pipe::AnonPipe;
-use crate::sys::{unsupported, Void};
-use crate::sys_common::process::CommandEnv;
-
-pub use crate::ffi::OsString as EnvKey;
-
-////////////////////////////////////////////////////////////////////////////////
-// Command
-////////////////////////////////////////////////////////////////////////////////
-
-pub struct Command {
-    env: CommandEnv,
-}
-
-// passed back to std::process with the pipes connected to the child, if any
-// were requested
-pub struct StdioPipes {
-    pub stdin: Option<AnonPipe>,
-    pub stdout: Option<AnonPipe>,
-    pub stderr: Option<AnonPipe>,
-}
-
-pub enum Stdio {
-    Inherit,
-    Null,
-    MakePipe,
-}
-
-impl Command {
-    pub fn new(_program: &OsStr) -> Command {
-        Command { env: Default::default() }
-    }
-
-    pub fn arg(&mut self, _arg: &OsStr) {}
-
-    pub fn env_mut(&mut self) -> &mut CommandEnv {
-        &mut self.env
-    }
-
-    pub fn cwd(&mut self, _dir: &OsStr) {}
-
-    pub fn stdin(&mut self, _stdin: Stdio) {}
-
-    pub fn stdout(&mut self, _stdout: Stdio) {}
-
-    pub fn stderr(&mut self, _stderr: Stdio) {}
-
-    pub fn spawn(
-        &mut self,
-        _default: Stdio,
-        _needs_stdin: bool,
-    ) -> io::Result<(Process, StdioPipes)> {
-        unsupported()
-    }
-}
-
-impl From<AnonPipe> for Stdio {
-    fn from(pipe: AnonPipe) -> Stdio {
-        pipe.diverge()
-    }
-}
-
-impl From<File> for Stdio {
-    fn from(_file: File) -> Stdio {
-        panic!("unsupported")
-    }
-}
-
-impl fmt::Debug for Command {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Ok(())
-    }
-}
-
-pub struct ExitStatus(Void);
-
-impl ExitStatus {
-    pub fn success(&self) -> bool {
-        match self.0 {}
-    }
-
-    pub fn code(&self) -> Option<i32> {
-        match self.0 {}
-    }
-}
-
-impl Clone for ExitStatus {
-    fn clone(&self) -> ExitStatus {
-        match self.0 {}
-    }
-}
-
-impl Copy for ExitStatus {}
-
-impl PartialEq for ExitStatus {
-    fn eq(&self, _other: &ExitStatus) -> bool {
-        match self.0 {}
-    }
-}
-
-impl Eq for ExitStatus {}
-
-impl fmt::Debug for ExitStatus {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0 {}
-    }
-}
-
-impl fmt::Display for ExitStatus {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.0 {}
-    }
-}
-
-#[derive(PartialEq, Eq, Clone, Copy, Debug)]
-pub struct ExitCode(bool);
-
-impl ExitCode {
-    pub const SUCCESS: ExitCode = ExitCode(false);
-    pub const FAILURE: ExitCode = ExitCode(true);
-
-    pub fn as_i32(&self) -> i32 {
-        self.0 as i32
-    }
-}
-
-pub struct Process(Void);
-
-impl Process {
-    pub fn id(&self) -> u32 {
-        match self.0 {}
-    }
-
-    pub fn kill(&mut self) -> io::Result<()> {
-        match self.0 {}
-    }
-
-    pub fn wait(&mut self) -> io::Result<ExitStatus> {
-        match self.0 {}
-    }
-
-    pub fn try_wait(&mut self) -> io::Result<Option<ExitStatus>> {
-        match self.0 {}
-    }
-}
diff --git a/library/std/src/sys/wasm/mod.rs b/library/std/src/sys/wasm/mod.rs
index 3de58904043..2934ea59ab5 100644
--- a/library/std/src/sys/wasm/mod.rs
+++ b/library/std/src/sys/wasm/mod.rs
@@ -27,7 +27,7 @@ pub mod io;
 pub mod net;
 #[path = "../unsupported/os.rs"]
 pub mod os;
-#[path = "../unsupported/path.rs"]
+#[path = "../unix/path.rs"]
 pub mod path;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index 794eeafbbbf..da27d2fbf99 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -195,6 +195,7 @@ target | std | host | notes
 `powerpc64-unknown-linux-musl` | ? |  |
 `powerpc64-wrs-vxworks` | ? |  |
 `powerpc64le-unknown-linux-musl` | ? |  |
+`riscv32gc-unknown-linux-gnu` |   |   | RISC-V Linux (kernel 5.4, glibc 2.33)
 `sparc-unknown-linux-gnu` | ✓ |  | 32-bit SPARC Linux
 `sparc64-unknown-netbsd` | ✓ | ✓ | NetBSD/sparc64
 `sparc64-unknown-openbsd` | ? |  |
diff --git a/src/librustdoc/Cargo.toml b/src/librustdoc/Cargo.toml
index 90d2a18ea58..a40a44fe27d 100644
--- a/src/librustdoc/Cargo.toml
+++ b/src/librustdoc/Cargo.toml
@@ -8,7 +8,7 @@ edition = "2018"
 path = "lib.rs"
 
 [dependencies]
-pulldown-cmark = { version = "0.7", default-features = false }
+pulldown-cmark = { version = "0.8", default-features = false }
 minifier = "0.0.33"
 rayon = { version = "0.3.0", package = "rustc-rayon" }
 serde = { version = "1.0", features = ["derive"] }
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index a8c60e4a76d..6c0f1c02ac6 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -27,7 +27,6 @@ use rustc_session::lint;
 use rustc_span::edition::Edition;
 use rustc_span::Span;
 use std::borrow::Cow;
-use std::cell::RefCell;
 use std::collections::VecDeque;
 use std::default::Default;
 use std::fmt::Write;
@@ -39,7 +38,7 @@ use crate::doctest;
 use crate::html::highlight;
 use crate::html::toc::TocBuilder;
 
-use pulldown_cmark::{html, CodeBlockKind, CowStr, Event, Options, Parser, Tag};
+use pulldown_cmark::{html, BrokenLink, CodeBlockKind, CowStr, Event, Options, Parser, Tag};
 
 #[cfg(test)]
 mod tests;
@@ -931,15 +930,17 @@ impl Markdown<'_> {
         if md.is_empty() {
             return String::new();
         }
-        let replacer = |_: &str, s: &str| {
-            if let Some(link) = links.iter().find(|link| &*link.original_text == s) {
-                Some((link.href.clone(), link.new_text.clone()))
+        let mut replacer = |broken_link: BrokenLink<'_>| {
+            if let Some(link) =
+                links.iter().find(|link| &*link.original_text == broken_link.reference)
+            {
+                Some((link.href.as_str().into(), link.new_text.as_str().into()))
             } else {
                 None
             }
         };
 
-        let p = Parser::new_with_broken_link_callback(md, opts(), Some(&replacer));
+        let p = Parser::new_with_broken_link_callback(md, opts(), Some(&mut replacer));
 
         let mut s = String::with_capacity(md.len() * 3 / 2);
 
@@ -1009,9 +1010,11 @@ impl MarkdownSummaryLine<'_> {
             return String::new();
         }
 
-        let replacer = |_: &str, s: &str| {
-            if let Some(link) = links.iter().find(|link| &*link.original_text == s) {
-                Some((link.href.clone(), link.new_text.clone()))
+        let mut replacer = |broken_link: BrokenLink<'_>| {
+            if let Some(link) =
+                links.iter().find(|link| &*link.original_text == broken_link.reference)
+            {
+                Some((link.href.as_str().into(), link.new_text.as_str().into()))
             } else {
                 None
             }
@@ -1020,7 +1023,7 @@ impl MarkdownSummaryLine<'_> {
         let p = Parser::new_with_broken_link_callback(
             md,
             Options::ENABLE_STRIKETHROUGH,
-            Some(&replacer),
+            Some(&mut replacer),
         );
 
         let mut s = String::new();
@@ -1067,7 +1070,7 @@ pub fn markdown_links(md: &str) -> Vec<(String, Option<Range<usize>>)> {
     }
 
     let mut links = vec![];
-    let shortcut_links = RefCell::new(vec![]);
+    let mut shortcut_links = vec![];
 
     {
         let locate = |s: &str| unsafe {
@@ -1084,11 +1087,13 @@ pub fn markdown_links(md: &str) -> Vec<(String, Option<Range<usize>>)> {
             }
         };
 
-        let push = |_: &str, s: &str| {
-            shortcut_links.borrow_mut().push((s.to_owned(), locate(s)));
+        let mut push = |link: BrokenLink<'_>| {
+            // FIXME: use `link.span` instead of `locate`
+            // (doing it now includes the `[]` as well as the text)
+            shortcut_links.push((link.reference.to_owned(), locate(link.reference)));
             None
         };
-        let p = Parser::new_with_broken_link_callback(md, opts(), Some(&push));
+        let p = Parser::new_with_broken_link_callback(md, opts(), Some(&mut push));
 
         // There's no need to thread an IdMap through to here because
         // the IDs generated aren't going to be emitted anywhere.
@@ -1106,8 +1111,7 @@ pub fn markdown_links(md: &str) -> Vec<(String, Option<Range<usize>>)> {
         }
     }
 
-    let mut shortcut_links = shortcut_links.into_inner();
-    links.extend(shortcut_links.drain(..));
+    links.append(&mut shortcut_links);
 
     links
 }
diff --git a/src/test/codegen/issue-73396-bounds-check-after-position.rs b/src/test/codegen/issue-73396-bounds-check-after-position.rs
new file mode 100644
index 00000000000..e5f3ae45c07
--- /dev/null
+++ b/src/test/codegen/issue-73396-bounds-check-after-position.rs
@@ -0,0 +1,78 @@
+// min-llvm-version: 11.0.0
+// compile-flags: -O
+// ignore-debug: the debug assertions get in the way
+#![crate_type = "lib"]
+
+// Make sure no bounds checks are emitted when slicing or indexing
+// with an index from `position()` or `rposition()`.
+
+// CHECK-LABEL: @position_slice_to_no_bounds_check
+#[no_mangle]
+pub fn position_slice_to_no_bounds_check(s: &[u8]) -> &[u8] {
+    // CHECK-NOT: panic
+    // CHECK-NOT: slice_index_len_fail
+    if let Some(idx) = s.iter().position(|b| *b == b'\\') {
+        &s[..idx]
+    } else {
+        s
+    }
+}
+
+// CHECK-LABEL: @position_slice_from_no_bounds_check
+#[no_mangle]
+pub fn position_slice_from_no_bounds_check(s: &[u8]) -> &[u8] {
+    // CHECK-NOT: panic
+    // CHECK-NOT: slice_index_len_fail
+    if let Some(idx) = s.iter().position(|b| *b == b'\\') {
+        &s[idx..]
+    } else {
+        s
+    }
+}
+
+// CHECK-LABEL: @position_index_no_bounds_check
+#[no_mangle]
+pub fn position_index_no_bounds_check(s: &[u8]) -> u8 {
+    // CHECK-NOT: panic
+    // CHECK-NOT: slice_index_len_fail
+    if let Some(idx) = s.iter().position(|b| *b == b'\\') {
+        s[idx]
+    } else {
+        42
+    }
+}
+// CHECK-LABEL: @rposition_slice_to_no_bounds_check
+#[no_mangle]
+pub fn rposition_slice_to_no_bounds_check(s: &[u8]) -> &[u8] {
+    // CHECK-NOT: panic
+    // CHECK-NOT: slice_index_len_fail
+    if let Some(idx) = s.iter().rposition(|b| *b == b'\\') {
+        &s[..idx]
+    } else {
+        s
+    }
+}
+
+// CHECK-LABEL: @rposition_slice_from_no_bounds_check
+#[no_mangle]
+pub fn rposition_slice_from_no_bounds_check(s: &[u8]) -> &[u8] {
+    // CHECK-NOT: panic
+    // CHECK-NOT: slice_index_len_fail
+    if let Some(idx) = s.iter().rposition(|b| *b == b'\\') {
+        &s[idx..]
+    } else {
+        s
+    }
+}
+
+// CHECK-LABEL: @rposition_index_no_bounds_check
+#[no_mangle]
+pub fn rposition_index_no_bounds_check(s: &[u8]) -> u8 {
+    // CHECK-NOT: panic
+    // CHECK-NOT: slice_index_len_fail
+    if let Some(idx) = s.iter().rposition(|b| *b == b'\\') {
+        s[idx]
+    } else {
+        42
+    }
+}
diff --git a/src/test/rustdoc-ui/intra-link-double-anchor.rs b/src/test/rustdoc-ui/intra-link-double-anchor.rs
new file mode 100644
index 00000000000..a01211c4f32
--- /dev/null
+++ b/src/test/rustdoc-ui/intra-link-double-anchor.rs
@@ -0,0 +1,7 @@
+// check-pass
+
+// regression test for #73264
+// should only give one error
+/// docs [label][with#anchor#error]
+//~^ WARNING multiple anchors
+pub struct S;
diff --git a/src/test/rustdoc-ui/intra-link-double-anchor.stderr b/src/test/rustdoc-ui/intra-link-double-anchor.stderr
new file mode 100644
index 00000000000..3282ec8b793
--- /dev/null
+++ b/src/test/rustdoc-ui/intra-link-double-anchor.stderr
@@ -0,0 +1,10 @@
+warning: `with#anchor#error` contains multiple anchors
+  --> $DIR/intra-link-double-anchor.rs:5:18
+   |
+LL | /// docs [label][with#anchor#error]
+   |                  ^^^^^^^^^^^^^^^^^ contains invalid anchor
+   |
+   = note: `#[warn(broken_intra_doc_links)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/lint/lint-unconditional-recursion.stderr b/src/test/ui/lint/lint-unconditional-recursion.stderr
index 1770d71e2e2..fb884e31299 100644
--- a/src/test/ui/lint/lint-unconditional-recursion.stderr
+++ b/src/test/ui/lint/lint-unconditional-recursion.stderr
@@ -149,7 +149,7 @@ error: function cannot return without recursing
 LL |     fn deref(&self) -> &Baz {
    |     ^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
 LL |         self.as_ref()
-   |         ---- recursive call site
+   |         ------------- recursive call site
    |
    = help: a `loop` may express intention better if this is on purpose
 
diff --git a/src/test/ui/moves/move-deref-coercion.rs b/src/test/ui/moves/move-deref-coercion.rs
new file mode 100644
index 00000000000..41154388f56
--- /dev/null
+++ b/src/test/ui/moves/move-deref-coercion.rs
@@ -0,0 +1,33 @@
+use std::ops::Deref;
+
+struct NotCopy {
+    inner: bool
+}
+
+impl NotCopy {
+    fn inner_method(&self) {}
+}
+
+struct Foo {
+    first: NotCopy,
+    second: NotCopy
+}
+
+impl Deref for Foo {
+    type Target = NotCopy;
+    fn deref(&self) -> &NotCopy {
+        &self.second
+    }
+}
+
+fn use_field(val: Foo) {
+    let _val = val.first;
+    val.inner; //~ ERROR borrow of
+}
+
+fn use_method(val: Foo) {
+    let _val = val.first;
+    val.inner_method(); //~ ERROR borrow of
+}
+
+fn main() {}
diff --git a/src/test/ui/moves/move-deref-coercion.stderr b/src/test/ui/moves/move-deref-coercion.stderr
new file mode 100644
index 00000000000..e3bdf6d7832
--- /dev/null
+++ b/src/test/ui/moves/move-deref-coercion.stderr
@@ -0,0 +1,35 @@
+error[E0382]: borrow of partially moved value: `val`
+  --> $DIR/move-deref-coercion.rs:25:5
+   |
+LL |     let _val = val.first;
+   |                --------- value partially moved here
+LL |     val.inner;
+   |     ^^^^^^^^^ value borrowed here after partial move
+   |
+   = note: partial move occurs because `val.first` has type `NotCopy`, which does not implement the `Copy` trait
+   = note: borrow occurs due to deref coercion to `NotCopy`
+note: deref defined here
+  --> $DIR/move-deref-coercion.rs:17:5
+   |
+LL |     type Target = NotCopy;
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0382]: borrow of partially moved value: `val`
+  --> $DIR/move-deref-coercion.rs:30:5
+   |
+LL |     let _val = val.first;
+   |                --------- value partially moved here
+LL |     val.inner_method();
+   |     ^^^^^^^^^^^^^^^^^^ value borrowed here after partial move
+   |
+   = note: partial move occurs because `val.first` has type `NotCopy`, which does not implement the `Copy` trait
+   = note: borrow occurs due to deref coercion to `NotCopy`
+note: deref defined here
+  --> $DIR/move-deref-coercion.rs:17:5
+   |
+LL |     type Target = NotCopy;
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/no-capture-arc.stderr b/src/test/ui/no-capture-arc.stderr
index 0081841fec0..37032e73f19 100644
--- a/src/test/ui/no-capture-arc.stderr
+++ b/src/test/ui/no-capture-arc.stderr
@@ -1,5 +1,5 @@
 error[E0382]: borrow of moved value: `arc_v`
-  --> $DIR/no-capture-arc.rs:14:18
+  --> $DIR/no-capture-arc.rs:14:16
    |
 LL |     let arc_v = Arc::new(v);
    |         ----- move occurs because `arc_v` has type `Arc<Vec<i32>>`, which does not implement the `Copy` trait
@@ -10,7 +10,14 @@ LL |         assert_eq!((*arc_v)[3], 4);
    |                      ----- variable moved due to use in closure
 ...
 LL |     assert_eq!((*arc_v)[2], 3);
-   |                  ^^^^^ value borrowed here after move
+   |                ^^^^^^^^ value borrowed here after move
+   |
+   = note: borrow occurs due to deref coercion to `Vec<i32>`
+note: deref defined here
+  --> $SRC_DIR/alloc/src/sync.rs:LL:COL
+   |
+LL |     type Target = T;
+   |     ^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/no-reuse-move-arc.stderr b/src/test/ui/no-reuse-move-arc.stderr
index bb4e0871224..6f37d4c9d86 100644
--- a/src/test/ui/no-reuse-move-arc.stderr
+++ b/src/test/ui/no-reuse-move-arc.stderr
@@ -1,5 +1,5 @@
 error[E0382]: borrow of moved value: `arc_v`
-  --> $DIR/no-reuse-move-arc.rs:12:18
+  --> $DIR/no-reuse-move-arc.rs:12:16
    |
 LL |     let arc_v = Arc::new(v);
    |         ----- move occurs because `arc_v` has type `Arc<Vec<i32>>`, which does not implement the `Copy` trait
@@ -10,7 +10,14 @@ LL |         assert_eq!((*arc_v)[3], 4);
    |                      ----- variable moved due to use in closure
 ...
 LL |     assert_eq!((*arc_v)[2], 3);
-   |                  ^^^^^ value borrowed here after move
+   |                ^^^^^^^^ value borrowed here after move
+   |
+   = note: borrow occurs due to deref coercion to `Vec<i32>`
+note: deref defined here
+  --> $SRC_DIR/alloc/src/sync.rs:LL:COL
+   |
+LL |     type Target = T;
+   |     ^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/tools/cargo b/src/tools/cargo
-Subproject 875e0123259b0b6299903fe4aea0a12ecde9324
+Subproject 8777a6b1e8834899f51b7e09cc9b8d85b241711