Auto merge of #67485 - Centril:rollup-gt0opvr, r=Centril

Rollup of 7 pull requests

Successful merges:

 - #67059 (Fix too restrictive checks on Drop impls)
 - #67355 (Merge `ast::Mutability` and `mir::Mutability`)
 - #67393 (Enable opting out of specific default LLVM arguments.)
 - #67422 (Cleanup err codes)
 - #67462 (Make ptr::slice_from_raw_parts a const fn available under a feature flag)
 - #67467 (Test slice patterns more)
 - #67478 (Fix src/libcore/str/mod.rs doc comments)

Failed merges:

r? @ghost

src/libcore/ptr/mod.rs

@@ -259,7 +259,8 @@ pub(crate) struct FatPtr<T> {
 /// ```
 #[inline]
 #[unstable(feature = "slice_from_raw_parts", reason = "recently added", issue = "36925")]
-pub fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
+#[rustc_const_unstable(feature = "const_slice_from_raw_parts", issue = "67456")]
+pub const fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
     unsafe { Repr { raw: FatPtr { data, len } }.rust }
 }
 
@@ -275,7 +276,8 @@ pub fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
 /// [`from_raw_parts_mut`]: ../../std/slice/fn.from_raw_parts_mut.html
 #[inline]
 #[unstable(feature = "slice_from_raw_parts", reason = "recently added", issue = "36925")]
-pub fn slice_from_raw_parts_mut<T>(data: *mut T, len: usize) -> *mut [T] {
+#[rustc_const_unstable(feature = "const_slice_from_raw_parts", issue = "67456")]
+pub const fn slice_from_raw_parts_mut<T>(data: *mut T, len: usize) -> *mut [T] {
     unsafe { Repr { raw: FatPtr { data, len } }.rust_mut }
 }
 

src/libcore/str/mod.rs

@@ -2325,7 +2325,7 @@ impl str {
         i.get_mut(self)
     }
 
-    /// Returns a unchecked subslice of `str`.
+    /// Returns an unchecked subslice of `str`.
     ///
     /// This is the unchecked alternative to indexing the `str`.
     ///

src/libcore/tests/lib.rs

@@ -36,6 +36,9 @@
 #![feature(iter_is_partitioned)]
 #![feature(iter_order_by)]
 #![feature(cmp_min_max_by)]
+#![feature(slice_from_raw_parts)]
+#![feature(const_slice_from_raw_parts)]
+#![feature(const_raw_ptr_deref)]
 
 extern crate test;
 

src/libcore/tests/ptr.rs

@@ -1,6 +1,17 @@
 use core::cell::RefCell;
 use core::ptr::*;
 
+#[test]
+fn test_const_from_raw_parts() {
+    const SLICE: &[u8] = &[1, 2, 3, 4];
+    const FROM_RAW: &[u8] = unsafe { &*slice_from_raw_parts(SLICE.as_ptr(), SLICE.len()) };
+    assert_eq!(SLICE, FROM_RAW);
+
+    let slice = &[1, 2, 3, 4, 5];
+    let from_raw = unsafe { &*slice_from_raw_parts(slice.as_ptr(), 2) } ;
+    assert_eq!(&slice[..2], from_raw);
+}
+
 #[test]
 fn test() {
     unsafe {

src/librustc/hir/lowering.rs

@@ -2253,7 +2253,7 @@ impl<'a> LoweringContext<'a> {
                     let is_mutable_pat = match arg.pat.kind {
                         PatKind::Ident(BindingMode::ByValue(mt), _, _) |
                         PatKind::Ident(BindingMode::ByRef(mt), _, _) =>
-                            mt == Mutability::Mutable,
+                            mt == Mutability::Mut,
                         _ => false,
                     };
 
@@ -2264,7 +2264,7 @@ impl<'a> LoweringContext<'a> {
                         // the case where we have a mutable pattern to a reference as that would
                         // no longer be an `ImplicitSelf`.
                         TyKind::Rptr(_, ref mt) if mt.ty.kind.is_implicit_self() &&
-                            mt.mutbl == ast::Mutability::Mutable =>
+                            mt.mutbl == ast::Mutability::Mut =>
                                 hir::ImplicitSelfKind::MutRef,
                         TyKind::Rptr(_, ref mt) if mt.ty.kind.is_implicit_self() =>
                             hir::ImplicitSelfKind::ImmRef,
@@ -3068,10 +3068,10 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingAnnotation {
         match *b {
-            BindingMode::ByValue(Mutability::Immutable) => hir::BindingAnnotation::Unannotated,
-            BindingMode::ByRef(Mutability::Immutable) => hir::BindingAnnotation::Ref,
-            BindingMode::ByValue(Mutability::Mutable) => hir::BindingAnnotation::Mutable,
-            BindingMode::ByRef(Mutability::Mutable) => hir::BindingAnnotation::RefMut,
+            BindingMode::ByValue(Mutability::Not) => hir::BindingAnnotation::Unannotated,
+            BindingMode::ByRef(Mutability::Not) => hir::BindingAnnotation::Ref,
+            BindingMode::ByValue(Mutability::Mut) => hir::BindingAnnotation::Mutable,
+            BindingMode::ByRef(Mutability::Mut) => hir::BindingAnnotation::RefMut,
         }
     }
 

src/librustc/hir/lowering/expr.rs

@@ -1340,7 +1340,7 @@ impl LoweringContext<'_> {
     fn expr_mut_addr_of(&mut self, span: Span, e: P<hir::Expr>) -> hir::Expr {
         self.expr(
             span,
-            hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mutable, e),
+            hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e),
             ThinVec::new(),
         )
     }

src/librustc/hir/pat_util.rs

@@ -169,11 +169,10 @@ impl hir::Pat {
         self.each_binding(|annotation, _, _, _| {
             match annotation {
                 hir::BindingAnnotation::Ref => match result {
-                    None | Some(hir::Mutability::Immutable) =>
-                        result = Some(hir::Mutability::Immutable),
+                    None | Some(hir::Mutability::Not) => result = Some(hir::Mutability::Not),
                     _ => {}
                 }
-                hir::BindingAnnotation::RefMut => result = Some(hir::Mutability::Mutable),
+                hir::BindingAnnotation::RefMut => result = Some(hir::Mutability::Mut),
                 _ => {}
             }
         });

src/librustc/hir/print.rs

@@ -386,7 +386,7 @@ impl<'a> State<'a> {
             }
             hir::ForeignItemKind::Static(ref t, m) => {
                 self.head(visibility_qualified(&item.vis, "static"));
-                if m == hir::Mutability::Mutable {
+                if m == hir::Mutability::Mut {
                     self.word_space("mut");
                 }
                 self.print_ident(item.ident);
@@ -502,7 +502,7 @@ impl<'a> State<'a> {
             }
             hir::ItemKind::Static(ref ty, m, expr) => {
                 self.head(visibility_qualified(&item.vis, "static"));
-                if m == hir::Mutability::Mutable {
+                if m == hir::Mutability::Mut {
                     self.word_space("mut");
                 }
                 self.print_ident(item.ident);
@@ -1632,11 +1632,11 @@ impl<'a> State<'a> {
                 match binding_mode {
                     hir::BindingAnnotation::Ref => {
                         self.word_nbsp("ref");
-                        self.print_mutability(hir::Mutability::Immutable, false);
+                        self.print_mutability(hir::Mutability::Not, false);
                     }
                     hir::BindingAnnotation::RefMut => {
                         self.word_nbsp("ref");
-                        self.print_mutability(hir::Mutability::Mutable, false);
+                        self.print_mutability(hir::Mutability::Mut, false);
                     }
                     hir::BindingAnnotation::Unannotated => {}
                     hir::BindingAnnotation::Mutable => {
@@ -2065,8 +2065,8 @@ impl<'a> State<'a> {
 
     pub fn print_mutability(&mut self, mutbl: hir::Mutability, print_const: bool) {
         match mutbl {
-            hir::Mutability::Mutable => self.word_nbsp("mut"),
-            hir::Mutability::Immutable => if print_const { self.word_nbsp("const") },
+            hir::Mutability::Mut => self.word_nbsp("mut"),
+            hir::Mutability::Not => if print_const { self.word_nbsp("const") },
         }
     }
 

src/librustc/lint/internal.rs

@@ -132,7 +132,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TyTyKind {
                     }
                 }
             }
-            TyKind::Rptr(_, MutTy { ty: inner_ty, mutbl: Mutability::Immutable }) => {
+            TyKind::Rptr(_, MutTy { ty: inner_ty, mutbl: Mutability::Not }) => {
                 if let Some(impl_did) = cx.tcx.impl_of_method(ty.hir_id.owner_def_id()) {
                     if cx.tcx.impl_trait_ref(impl_did).is_some() {
                         return;

src/librustc/mir/interpret/allocation.rs

@@ -106,7 +106,7 @@ impl<Tag> Allocation<Tag> {
             undef_mask: UndefMask::new(size, true),
             size,
             align,
-            mutability: Mutability::Immutable,
+            mutability: Mutability::Not,
             extra: (),
         }
     }
@@ -123,7 +123,7 @@ impl<Tag> Allocation<Tag> {
             undef_mask: UndefMask::new(size, false),
             size,
             align,
-            mutability: Mutability::Mutable,
+            mutability: Mutability::Mut,
             extra: (),
         }
     }

src/librustc/mir/mod.rs

@@ -34,6 +34,7 @@ use std::ops::Index;
 use std::slice;
 use std::{iter, mem, option, u32};
 use syntax::ast::Name;
+pub use syntax::ast::Mutability;
 use syntax::symbol::Symbol;
 use syntax_pos::{Span, DUMMY_SP};
 
@@ -396,22 +397,7 @@ pub struct SourceInfo {
 }
 
 ///////////////////////////////////////////////////////////////////////////
-// Mutability and borrow kinds
-
-#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
-pub enum Mutability {
-    Mut,
-    Not,
-}
-
-impl From<Mutability> for hir::Mutability {
-    fn from(m: Mutability) -> Self {
-        match m {
-            Mutability::Mut => hir::Mutability::Mutable,
-            Mutability::Not => hir::Mutability::Immutable,
-        }
-    }
-}
+// Borrow kinds
 
 #[derive(
     Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
@@ -2886,7 +2872,6 @@ pub enum ClosureOutlivesSubject<'tcx> {
 CloneTypeFoldableAndLiftImpls! {
     BlockTailInfo,
     MirPhase,
-    Mutability,
     SourceInfo,
     FakeReadCause,
     RetagKind,

src/librustc/mir/tcx.rs

@@ -279,17 +279,17 @@ impl<'tcx> BinOp {
 impl BorrowKind {
     pub fn to_mutbl_lossy(self) -> hir::Mutability {
         match self {
-            BorrowKind::Mut { .. } => hir::Mutability::Mutable,
-            BorrowKind::Shared => hir::Mutability::Immutable,
+            BorrowKind::Mut { .. } => hir::Mutability::Mut,
+            BorrowKind::Shared => hir::Mutability::Not,
 
             // We have no type corresponding to a unique imm borrow, so
             // use `&mut`. It gives all the capabilities of an `&uniq`
             // and hence is a safe "over approximation".
-            BorrowKind::Unique => hir::Mutability::Mutable,
+            BorrowKind::Unique => hir::Mutability::Mut,
 
             // We have no type corresponding to a shallow borrow, so use
             // `&` as an approximation.
-            BorrowKind::Shallow => hir::Mutability::Immutable,
+            BorrowKind::Shallow => hir::Mutability::Not,
         }
     }
 }

src/librustc/traits/error_reporting.rs

@@ -1548,8 +1548,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
             if let ty::Ref(region, t_type, mutability) = trait_ref.skip_binder().self_ty().kind {
                 let trait_type = match mutability {
-                    hir::Mutability::Mutable => self.tcx.mk_imm_ref(region, t_type),
-                    hir::Mutability::Immutable => self.tcx.mk_mut_ref(region, t_type),
+                    hir::Mutability::Mut => self.tcx.mk_imm_ref(region, t_type),
+                    hir::Mutability::Not => self.tcx.mk_mut_ref(region, t_type),
                 };
 
                 let new_obligation = self.mk_obligation_for_def_id(
@@ -1565,7 +1565,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     let sp = self.tcx.sess.source_map()
                         .span_take_while(span, |c| c.is_whitespace() || *c == '&');
                     if points_at_arg &&
-                        mutability == hir::Mutability::Immutable &&
+                        mutability == hir::Mutability::Not &&
                         refs_number > 0
                     {
                         err.span_suggestion(

src/librustc/traits/select.rs

@@ -2622,7 +2622,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::Char
             | ty::RawPtr(..)
             | ty::Never
-            | ty::Ref(_, _, hir::Mutability::Immutable) => {
+            | ty::Ref(_, _, hir::Mutability::Not) => {
                 // Implementations provided in libcore
                 None
             }
@@ -2633,7 +2633,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::Generator(..)
             | ty::GeneratorWitness(..)
             | ty::Foreign(..)
-            | ty::Ref(_, _, hir::Mutability::Mutable) => None,
+            | ty::Ref(_, _, hir::Mutability::Mut) => None,
 
             ty::Array(element_ty, _) => {
                 // (*) binder moved here

src/librustc/ty/adjustment.rs

@@ -109,8 +109,8 @@ pub struct OverloadedDeref<'tcx> {
 impl<'tcx> OverloadedDeref<'tcx> {
     pub fn method_call(&self, tcx: TyCtxt<'tcx>, source: Ty<'tcx>) -> (DefId, SubstsRef<'tcx>) {
         let trait_def_id = match self.mutbl {
-            hir::Mutability::Immutable => tcx.lang_items().deref_trait(),
-            hir::Mutability::Mutable => tcx.lang_items().deref_mut_trait()
+            hir::Mutability::Not => tcx.lang_items().deref_trait(),
+            hir::Mutability::Mut => tcx.lang_items().deref_mut_trait()
         };
         let method_def_id = tcx.associated_items(trait_def_id.unwrap())
             .find(|m| m.kind == ty::AssocKind::Method).unwrap().def_id;
@@ -138,15 +138,15 @@ pub enum AllowTwoPhase {
 
 #[derive(Copy, Clone, PartialEq, Debug, RustcEncodable, RustcDecodable, HashStable)]
 pub enum AutoBorrowMutability {
-    Mutable { allow_two_phase_borrow: AllowTwoPhase },
-    Immutable,
+    Mut { allow_two_phase_borrow: AllowTwoPhase },
+    Not,
 }
 
 impl From<AutoBorrowMutability> for hir::Mutability {
     fn from(m: AutoBorrowMutability) -> Self {
         match m {
-            AutoBorrowMutability::Mutable { .. } => hir::Mutability::Mutable,
-            AutoBorrowMutability::Immutable => hir::Mutability::Immutable,
+            AutoBorrowMutability::Mut { .. } => hir::Mutability::Mut,
+            AutoBorrowMutability::Not => hir::Mutability::Not,
         }
     }
 }

src/librustc/ty/binding.rs

@@ -13,10 +13,10 @@ CloneTypeFoldableAndLiftImpls! { BindingMode, }
 impl BindingMode {
     pub fn convert(ba: BindingAnnotation) -> BindingMode {
         match ba {
-            Unannotated => BindingMode::BindByValue(Mutability::Immutable),
-            Mutable => BindingMode::BindByValue(Mutability::Mutable),
-            Ref => BindingMode::BindByReference(Mutability::Immutable),
-            RefMut => BindingMode::BindByReference(Mutability::Mutable),
+            Unannotated => BindingMode::BindByValue(Mutability::Not),
+            Mutable => BindingMode::BindByValue(Mutability::Mut),
+            Ref => BindingMode::BindByReference(Mutability::Not),
+            RefMut => BindingMode::BindByReference(Mutability::Mut),
         }
     }
 }

src/librustc/ty/context.rs

@@ -2406,22 +2406,22 @@ impl<'tcx> TyCtxt<'tcx> {
 
     #[inline]
     pub fn mk_mut_ref(self, r: Region<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
-        self.mk_ref(r, TypeAndMut {ty: ty, mutbl: hir::Mutability::Mutable})
+        self.mk_ref(r, TypeAndMut {ty: ty, mutbl: hir::Mutability::Mut })
     }
 
     #[inline]
     pub fn mk_imm_ref(self, r: Region<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
-        self.mk_ref(r, TypeAndMut {ty: ty, mutbl: hir::Mutability::Immutable})
+        self.mk_ref(r, TypeAndMut {ty: ty, mutbl: hir::Mutability::Not })
     }
 
     #[inline]
     pub fn mk_mut_ptr(self, ty: Ty<'tcx>) -> Ty<'tcx> {
-        self.mk_ptr(TypeAndMut {ty: ty, mutbl: hir::Mutability::Mutable})
+        self.mk_ptr(TypeAndMut {ty: ty, mutbl: hir::Mutability::Mut })
     }
 
     #[inline]
     pub fn mk_imm_ptr(self, ty: Ty<'tcx>) -> Ty<'tcx> {
-        self.mk_ptr(TypeAndMut {ty: ty, mutbl: hir::Mutability::Immutable})
+        self.mk_ptr(TypeAndMut {ty: ty, mutbl: hir::Mutability::Not })
     }
 
     #[inline]

src/librustc/ty/error.rs

@@ -248,7 +248,7 @@ impl<'tcx> ty::TyS<'tcx> {
                     format!("`&{}`", tymut_string).into()
                 } else { // Unknown type name, it's long or has type arguments
                     match mutbl {
-                        hir::Mutability::Mutable => "mutable reference",
+                        hir::Mutability::Mut => "mutable reference",
                         _ => "reference",
                     }.into()
                 }
@@ -293,7 +293,7 @@ impl<'tcx> ty::TyS<'tcx> {
             ty::Slice(_) => "slice".into(),
             ty::RawPtr(_) => "raw pointer".into(),
             ty::Ref(.., mutbl) => match mutbl {
-                hir::Mutability::Mutable => "mutable reference",
+                hir::Mutability::Mut => "mutable reference",
                 _ => "reference"
             }.into(),
             ty::FnDef(..) => "fn item".into(),

src/librustc/ty/layout.rs

@@ -2221,12 +2221,12 @@ where
                 let tcx = cx.tcx();
                 let is_freeze = ty.is_freeze(tcx, cx.param_env(), DUMMY_SP);
                 let kind = match mt {
-                    hir::Mutability::Immutable => if is_freeze {
+                    hir::Mutability::Not => if is_freeze {
                         PointerKind::Frozen
                     } else {
                         PointerKind::Shared
                     },
-                    hir::Mutability::Mutable => {
+                    hir::Mutability::Mut => {
                         // Previously we would only emit noalias annotations for LLVM >= 6 or in
                         // panic=abort mode. That was deemed right, as prior versions had many bugs
                         // in conjunction with unwinding, but later versions didn’t seem to have