Auto merge of #151911 - JonathanBrouwer:rollup-ACi3J2a, r=JonathanBrouwer

Rollup of 3 pull requests

Successful merges:

 - #151908 (Remove unused method `DroplessArena::contains_slice`)
 - #151850 (refactor: add an `enum DerefAdjustKind` in favor of `Option<OverloadedDeref>`)
 - #151889 (Fix ICE when parsing frontmatter without newline)

Author: bors

compiler/rustc_arena/src/lib.rs

@@ -510,19 +510,6 @@ impl DroplessArena {
         }
     }
 
-    /// Used by `Lift` to check whether this slice is allocated
-    /// in this arena.
-    #[inline]
-    pub fn contains_slice<T>(&self, slice: &[T]) -> bool {
-        for chunk in self.chunks.borrow_mut().iter_mut() {
-            let ptr = slice.as_ptr().cast::<u8>().cast_mut();
-            if chunk.start() <= ptr && chunk.end() >= ptr {
-                return true;
-            }
-        }
-        false
-    }
-
     /// Allocates a string slice that is copied into the `DroplessArena`, returning a
     /// reference to it. Will panic if passed an empty string.
     ///

compiler/rustc_hir_typeck/src/autoderef.rs

@@ -6,7 +6,7 @@ use itertools::Itertools;
 use rustc_hir_analysis::autoderef::{Autoderef, AutoderefKind};
 use rustc_infer::infer::InferOk;
 use rustc_infer::traits::PredicateObligations;
-use rustc_middle::ty::adjustment::{Adjust, Adjustment, OverloadedDeref};
+use rustc_middle::ty::adjustment::{Adjust, Adjustment, DerefAdjustKind, OverloadedDeref};
 use rustc_middle::ty::{self, Ty};
 use rustc_span::Span;
 
@@ -45,22 +45,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             steps.iter().skip(1).map(|&(ty, _)| ty).chain(iter::once(autoderef.final_ty()));
         let steps: Vec<_> = steps
             .iter()
-            .map(|&(source, kind)| {
-                if let AutoderefKind::Overloaded = kind {
-                    self.try_overloaded_deref(autoderef.span(), source).and_then(
-                        |InferOk { value: method, obligations: o }| {
+            .map(|&(source, kind)| match kind {
+                AutoderefKind::Overloaded => {
+                    self.try_overloaded_deref(autoderef.span(), source)
+                        .and_then(|InferOk { value: method, obligations: o }| {
                             obligations.extend(o);
                             // FIXME: we should assert the sig is &T here... there's no reason for this to be fallible.
                             if let ty::Ref(_, _, mutbl) = *method.sig.output().kind() {
-                                Some(OverloadedDeref { mutbl, span: autoderef.span() })
+                                Some(DerefAdjustKind::Overloaded(OverloadedDeref {
+                                    mutbl,
+                                    span: autoderef.span(),
+                                }))
                             } else {
                                 None
                             }
-                        },
-                    )
-                } else {
-                    None
+                        })
+                        .unwrap_or(DerefAdjustKind::Builtin)
                 }
+                AutoderefKind::Builtin => DerefAdjustKind::Builtin,
             })
             .zip_eq(targets)
             .map(|(autoderef, target)| Adjustment { kind: Adjust::Deref(autoderef), target })

compiler/rustc_hir_typeck/src/coercion.rs

@@ -50,7 +50,8 @@ use rustc_infer::traits::{
 };
 use rustc_middle::span_bug;
 use rustc_middle::ty::adjustment::{
-    Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, PointerCoercion,
+    Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, DerefAdjustKind,
+    PointerCoercion,
 };
 use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
@@ -595,7 +596,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                 let mutbl = AutoBorrowMutability::new(mutbl_b, AllowTwoPhase::No);
 
                 Some((
-                    Adjustment { kind: Adjust::Deref(None), target: ty_a },
+                    Adjustment { kind: Adjust::Deref(DerefAdjustKind::Builtin), target: ty_a },
                     Adjustment {
                         kind: Adjust::Borrow(AutoBorrow::Ref(mutbl)),
                         target: Ty::new_ref(self.tcx, r_borrow, ty_a, mutbl_b),
@@ -606,7 +607,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                 coerce_mutbls(mt_a, mt_b)?;
 
                 Some((
-                    Adjustment { kind: Adjust::Deref(None), target: ty_a },
+                    Adjustment { kind: Adjust::Deref(DerefAdjustKind::Builtin), target: ty_a },
                     Adjustment {
                         kind: Adjust::Borrow(AutoBorrow::RawPtr(mt_b)),
                         target: Ty::new_ptr(self.tcx, ty_a, mt_b),
@@ -936,7 +937,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             self.unify_and(
                 a_raw,
                 b,
-                [Adjustment { kind: Adjust::Deref(None), target: mt_a.ty }],
+                [Adjustment { kind: Adjust::Deref(DerefAdjustKind::Builtin), target: mt_a.ty }],
                 Adjust::Borrow(AutoBorrow::RawPtr(mutbl_b)),
                 ForceLeakCheck::No,
             )

compiler/rustc_hir_typeck/src/expr_use_visitor.rs

@@ -22,6 +22,7 @@ use rustc_middle::hir::place::ProjectionKind;
 pub use rustc_middle::hir::place::{Place, PlaceBase, PlaceWithHirId, Projection};
 use rustc_middle::mir::FakeReadCause;
 use rustc_middle::thir::DerefPatBorrowMode;
+use rustc_middle::ty::adjustment::DerefAdjustKind;
 use rustc_middle::ty::{
     self, BorrowKind, Ty, TyCtxt, TypeFoldable, TypeVisitableExt as _, adjustment,
 };
@@ -733,14 +734,14 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx
                     self.consume_or_copy(&place_with_id, place_with_id.hir_id);
                 }
 
-                adjustment::Adjust::Deref(None) => {}
+                adjustment::Adjust::Deref(DerefAdjustKind::Builtin) => {}
 
                 // Autoderefs for overloaded Deref calls in fact reference
                 // their receiver. That is, if we have `(*x)` where `x`
                 // is of type `Rc<T>`, then this in fact is equivalent to
                 // `x.deref()`. Since `deref()` is declared with `&self`,
                 // this is an autoref of `x`.
-                adjustment::Adjust::Deref(Some(ref deref)) => {
+                adjustment::Adjust::Deref(DerefAdjustKind::Overloaded(deref)) => {
                     let bk = ty::BorrowKind::from_mutbl(deref.mutbl);
                     self.delegate.borrow_mut().borrow(&place_with_id, place_with_id.hir_id, bk);
                 }
@@ -1272,9 +1273,9 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx
     {
         let target = self.cx.resolve_vars_if_possible(adjustment.target);
         match adjustment.kind {
-            adjustment::Adjust::Deref(overloaded) => {
+            adjustment::Adjust::Deref(deref_kind) => {
                 // Equivalent to *expr or something similar.
-                let base = if let Some(deref) = overloaded {
+                let base = if let DerefAdjustKind::Overloaded(deref) = deref_kind {
                     let ref_ty = Ty::new_ref(
                         self.cx.tcx(),
                         self.cx.tcx().lifetimes.re_erased,

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -20,7 +20,9 @@ use rustc_hir_analysis::hir_ty_lowering::{
 use rustc_infer::infer::canonical::{Canonical, OriginalQueryValues, QueryResponse};
 use rustc_infer::infer::{DefineOpaqueTypes, InferResult};
 use rustc_lint::builtin::SELF_CONSTRUCTOR_FROM_OUTER_ITEM;
-use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
+use rustc_middle::ty::adjustment::{
+    Adjust, Adjustment, AutoBorrow, AutoBorrowMutability, DerefAdjustKind,
+};
 use rustc_middle::ty::{
     self, AdtKind, CanonicalUserType, GenericArgsRef, GenericParamDefKind, IsIdentity,
     SizedTraitKind, Ty, TyCtxt, TypeFoldable, TypeVisitable, TypeVisitableExt, UserArgs,
@@ -266,15 +268,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         debug!("apply_adjustments: adding `{:?}` as diverging type var", a.target);
                     }
                 }
-                Adjust::Deref(Some(overloaded_deref)) => {
+                Adjust::Deref(DerefAdjustKind::Overloaded(overloaded_deref)) => {
                     self.enforce_context_effects(
                         None,
                         expr.span,
                         overloaded_deref.method_call(self.tcx),
                         self.tcx.mk_args(&[expr_ty.into()]),
                     );
                 }
-                Adjust::Deref(None) => {
+                Adjust::Deref(DerefAdjustKind::Builtin) => {
                     // FIXME(const_trait_impl): We *could* enforce `&T: [const] Deref` here.
                 }
                 Adjust::Pointer(_pointer_coercion) => {

compiler/rustc_hir_typeck/src/place_op.rs

@@ -4,8 +4,8 @@ use rustc_infer::infer::InferOk;
 use rustc_infer::traits::{Obligation, ObligationCauseCode};
 use rustc_middle::span_bug;
 use rustc_middle::ty::adjustment::{
-    Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, OverloadedDeref,
-    PointerCoercion,
+    Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, DerefAdjustKind,
+    OverloadedDeref, PointerCoercion,
 };
 use rustc_middle::ty::{self, Ty};
 use rustc_span::{Span, sym};
@@ -298,7 +298,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.typeck_results.borrow_mut().adjustments_mut().remove(expr.hir_id);
             if let Some(mut adjustments) = previous_adjustments {
                 for adjustment in &mut adjustments {
-                    if let Adjust::Deref(Some(ref mut deref)) = adjustment.kind
+                    if let Adjust::Deref(DerefAdjustKind::Overloaded(ref mut deref)) =
+                        adjustment.kind
                         && let Some(ok) = self.try_mutable_overloaded_place_op(
                             expr.span,
                             source,

compiler/rustc_lint/src/autorefs.rs

@@ -1,7 +1,9 @@
 use rustc_ast::{BorrowKind, UnOp};
 use rustc_hir::attrs::AttributeKind;
 use rustc_hir::{Expr, ExprKind, Mutability, find_attr};
-use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, OverloadedDeref};
+use rustc_middle::ty::adjustment::{
+    Adjust, Adjustment, AutoBorrow, DerefAdjustKind, OverloadedDeref,
+};
 use rustc_session::{declare_lint, declare_lint_pass};
 
 use crate::lints::{
@@ -165,12 +167,14 @@ fn peel_derefs_adjustments<'a>(mut adjs: &'a [Adjustment<'a>]) -> &'a [Adjustmen
 /// an implicit borrow (or has an implicit borrow via an overloaded deref).
 fn has_implicit_borrow(Adjustment { kind, .. }: &Adjustment<'_>) -> Option<(Mutability, bool)> {
     match kind {
-        &Adjust::Deref(Some(OverloadedDeref { mutbl, .. })) => Some((mutbl, true)),
+        &Adjust::Deref(DerefAdjustKind::Overloaded(OverloadedDeref { mutbl, .. })) => {
+            Some((mutbl, true))
+        }
         &Adjust::Borrow(AutoBorrow::Ref(mutbl)) => Some((mutbl.into(), false)),
         Adjust::NeverToAny
         | Adjust::Pointer(..)
         | Adjust::ReborrowPin(..)
-        | Adjust::Deref(None)
+        | Adjust::Deref(DerefAdjustKind::Builtin)
         | Adjust::Borrow(AutoBorrow::RawPtr(..)) => None,
     }
 }

compiler/rustc_lint/src/noop_method_call.rs

@@ -1,7 +1,7 @@
 use rustc_hir::def::DefKind;
 use rustc_hir::{Expr, ExprKind};
 use rustc_middle::ty;
-use rustc_middle::ty::adjustment::Adjust;
+use rustc_middle::ty::adjustment::{Adjust, DerefAdjustKind};
 use rustc_session::{declare_lint, declare_lint_pass};
 use rustc_span::sym;
 
@@ -114,7 +114,10 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
 
         // If there is any user defined auto-deref step, then we don't want to warn.
         // https://github.com/rust-lang/rust-clippy/issues/9272
-        if arg_adjustments.iter().any(|adj| matches!(adj.kind, Adjust::Deref(Some(_)))) {
+        if arg_adjustments
+            .iter()
+            .any(|adj| matches!(adj.kind, Adjust::Deref(DerefAdjustKind::Overloaded(_))))
+        {
             return;
         }
 

compiler/rustc_middle/src/ty/adjustment.rs

@@ -97,7 +97,7 @@ pub enum Adjust {
     NeverToAny,
 
     /// Dereference once, producing a place.
-    Deref(Option<OverloadedDeref>),
+    Deref(DerefAdjustKind),
 
     /// Take the address and produce either a `&` or `*` pointer.
     Borrow(AutoBorrow),
@@ -108,6 +108,12 @@ pub enum Adjust {
     ReborrowPin(hir::Mutability),
 }
 
+#[derive(Copy, Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
+pub enum DerefAdjustKind {
+    Builtin,
+    Overloaded(OverloadedDeref),
+}
+
 /// An overloaded autoderef step, representing a `Deref(Mut)::deref(_mut)`
 /// call, with the signature `&'a T -> &'a U` or `&'a mut T -> &'a mut U`.
 /// The target type is `U` in both cases, with the region and mutability

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -14,7 +14,7 @@ use rustc_middle::middle::region;
 use rustc_middle::mir::{self, AssignOp, BinOp, BorrowKind, UnOp};
 use rustc_middle::thir::*;
 use rustc_middle::ty::adjustment::{
-    Adjust, Adjustment, AutoBorrow, AutoBorrowMutability, PointerCoercion,
+    Adjust, Adjustment, AutoBorrow, AutoBorrowMutability, DerefAdjustKind, PointerCoercion,
 };
 use rustc_middle::ty::{
     self, AdtKind, GenericArgs, InlineConstArgs, InlineConstArgsParts, ScalarInt, Ty, UpvarArgs,
@@ -140,11 +140,11 @@ impl<'tcx> ThirBuildCx<'tcx> {
             }
             Adjust::NeverToAny if adjustment.target.is_never() => return expr,
             Adjust::NeverToAny => ExprKind::NeverToAny { source: self.thir.exprs.push(expr) },
-            Adjust::Deref(None) => {
+            Adjust::Deref(DerefAdjustKind::Builtin) => {
                 adjust_span(&mut expr);
                 ExprKind::Deref { arg: self.thir.exprs.push(expr) }
             }
-            Adjust::Deref(Some(deref)) => {
+            Adjust::Deref(DerefAdjustKind::Overloaded(deref)) => {
                 // We don't need to do call adjust_span here since
                 // deref coercions always start with a built-in deref.
                 let call_def_id = deref.method_call(self.tcx);