Auto merge of #65671 - Centril:rollup-00glhmb, r=Centril

Rollup of 7 pull requests

Successful merges:

 - #62330 (Change untagged_unions to not allow union fields with drop)
 - #65092 (make is_power_of_two a const function)
 - #65621 (miri: add write_bytes method to Memory doing bounds-checks and supporting iterators)
 - #65647 (Remove unnecessary trait bounds and derivations)
 - #65653 (keep the root dir clean from debugging)
 - #65660 (Rename `ConstValue::Infer(InferConst::Canonical(..))` to `ConstValue::Bound(..)`)
 - #65663 (Fix typo from #65214)

Failed merges:

r? @ghost

.gitignore

@@ -1,6 +1,10 @@
-# This file should only ignore things that are generated during a build,
-# generated by common IDEs, and optional files controlled by the user
-# that affect the build (such as config.toml).
+# This file should only ignore things that are generated during a `x.py` build,
+# generated by common IDEs, and optional files controlled by the user that
+# affect the build (such as config.toml).
+# In particular, things like `mir_dump` should not be listed here; they are only
+# created during manual debugging and many people like to clean up instead of
+# having git ignore such leftovers. You can use `.git/info/exclude` to
+# configure your local ignore list.
 # FIXME: This needs cleanup.
 *~
 .#*
@@ -52,6 +56,4 @@ config.stamp
 Session.vim
 .cargo
 no_llvm_build
-# Generated when dumping Graphviz output for debugging:
-/mir_dump/
-/*.dot
+# Before adding new lines, see the comment at the top.

src/bootstrap/cache.rs

@@ -161,7 +161,7 @@ impl Ord for Interned<String> {
     }
 }
 
-struct TyIntern<T: Hash + Clone + Eq> {
+struct TyIntern<T: Clone + Eq> {
     items: Vec<T>,
     set: HashMap<T, Interned<T>>,
 }

src/doc/rustc/src/lints/listing/warn-by-default.md

@@ -596,30 +596,6 @@ warning: function cannot return without recursing
   |
 ```
 
-## unions-with-drop-fields
-
-This lint detects use of unions that contain fields with possibly non-trivial drop code. Some
-example code that triggers this lint:
-
-```rust
-#![feature(untagged_unions)]
-
-union U {
-    s: String,
-}
-```
-
-This will produce:
-
-```text
-warning: union contains a field with possibly non-trivial drop code, drop code of union fields is ignored when dropping the union
- --> src/main.rs:4:5
-  |
-4 |     s: String,
-  |     ^^^^^^^^^
-  |
-```
-
 ## unknown-lints
 
 This lint detects unrecognized lint attribute. Some

src/libcore/num/mod.rs

@@ -3757,8 +3757,8 @@ assert!(!10", stringify!($SelfT), ".is_power_of_two());", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
             #[inline]
-            pub fn is_power_of_two(self) -> bool {
-                (self.wrapping_sub(1)) & self == 0 && !(self == 0)
+            pub const fn is_power_of_two(self) -> bool {
+                self.count_ones() == 1
             }
         }
 

src/librustc/Cargo.toml

@@ -36,5 +36,5 @@ parking_lot = "0.9"
 byteorder = { version = "1.3" }
 chalk-engine = { version = "0.9.0", default-features=false }
 rustc_fs_util = { path = "../librustc_fs_util" }
-smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
+smallvec = { version = "0.6.8", features = ["union", "may_dangle"] }
 measureme = "0.3"

src/librustc/dep_graph/graph.rs

@@ -35,7 +35,7 @@ impl DepNodeIndex {
     pub const INVALID: DepNodeIndex = DepNodeIndex::MAX;
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(PartialEq)]
 pub enum DepNodeColor {
     Red,
     Green(DepNodeIndex)

src/librustc/hir/map/definitions.rs

@@ -599,7 +599,6 @@ macro_rules! define_global_metadata_kind {
     (pub enum GlobalMetaDataKind {
         $($variant:ident),*
     }) => (
-        #[derive(Clone, Copy, Debug, Hash, RustcEncodable, RustcDecodable)]
         pub enum GlobalMetaDataKind {
             $($variant),*
         }

src/librustc/hir/mod.rs

@@ -1077,7 +1077,7 @@ impl Mutability {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Hash, HashStable)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable)]
 pub enum BinOpKind {
     /// The `+` operator (addition).
     Add,
@@ -1211,7 +1211,7 @@ impl Into<ast::BinOpKind> for BinOpKind {
 
 pub type BinOp = Spanned<BinOpKind>;
 
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Hash, HashStable)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable)]
 pub enum UnOp {
     /// The `*` operator (deferencing).
     UnDeref,
@@ -1388,8 +1388,7 @@ impl Body {
 }
 
 /// The type of source expression that caused this generator to be created.
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, HashStable,
-         RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, Eq, HashStable, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum GeneratorKind {
     /// An explicit `async` block or the body of an async function.
     Async(AsyncGeneratorKind),
@@ -1412,8 +1411,7 @@ impl fmt::Display for GeneratorKind {
 ///
 /// This helps error messages but is also used to drive coercions in
 /// type-checking (see #60424).
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, HashStable,
-         RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, Eq, HashStable, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum AsyncGeneratorKind {
     /// An explicit `async` block written by the user.
     Block,

src/librustc/hir/ptr.rs

@@ -11,7 +11,7 @@ use rustc_serialize::{Encodable, Decodable, Encoder, Decoder};
 
 use rustc_data_structures::stable_hasher::{StableHasher, HashStable};
 /// An owned smart pointer.
-#[derive(Hash, PartialEq, Eq)]
+#[derive(PartialEq, Eq)]
 pub struct P<T: ?Sized> {
     ptr: Box<T>
 }

src/librustc/infer/canonical/canonicalizer.rs

@@ -468,7 +468,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Canonicalizer<'cx, 'tcx> {
             ConstValue::Infer(InferConst::Fresh(_)) => {
                 bug!("encountered a fresh const during canonicalization")
             }
-            ConstValue::Infer(InferConst::Canonical(debruijn, _)) => {
+            ConstValue::Bound(debruijn, _) => {
                 if debruijn >= self.binder_index {
                     bug!("escaping bound type during canonicalization")
                 } else {
@@ -700,7 +700,7 @@ impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
             let var = self.canonical_var(info, const_var.into());
             self.tcx().mk_const(
                 ty::Const {
-                    val: ConstValue::Infer(InferConst::Canonical(self.binder_index, var.into())),
+                    val: ConstValue::Bound(self.binder_index, var.into()),
                     ty: self.fold_ty(const_var.ty),
                 }
             )

src/librustc/infer/canonical/mod.rs

@@ -33,7 +33,7 @@ use std::ops::Index;
 use syntax::source_map::Span;
 use crate::ty::fold::TypeFoldable;
 use crate::ty::subst::GenericArg;
-use crate::ty::{self, BoundVar, InferConst, Lift, List, Region, TyCtxt};
+use crate::ty::{self, BoundVar, Lift, List, Region, TyCtxt};
 
 mod canonicalizer;
 
@@ -73,7 +73,7 @@ pub struct CanonicalVarValues<'tcx> {
 /// various parts of it with canonical variables. This struct stores
 /// those replaced bits to remember for when we process the query
 /// result.
-#[derive(Clone, Debug, PartialEq, Eq, Hash, RustcDecodable, RustcEncodable)]
+#[derive(Clone, Debug)]
 pub struct OriginalQueryValues<'tcx> {
     /// Map from the universes that appear in the query to the
     /// universes in the caller context. For the time being, we only
@@ -510,9 +510,7 @@ impl<'tcx> CanonicalVarValues<'tcx> {
                     GenericArgKind::Const(ct) => {
                         tcx.mk_const(ty::Const {
                             ty: ct.ty,
-                            val: ConstValue::Infer(
-                                InferConst::Canonical(ty::INNERMOST, ty::BoundVar::from_u32(i))
-                            ),
+                            val: ConstValue::Bound(ty::INNERMOST, ty::BoundVar::from_u32(i)),
                         }).into()
                     }
                 })

src/librustc/infer/canonical/query_response.rs

@@ -26,7 +26,7 @@ use crate::traits::TraitEngine;
 use crate::traits::{Obligation, ObligationCause, PredicateObligation};
 use crate::ty::fold::TypeFoldable;
 use crate::ty::subst::{GenericArg, GenericArgKind};
-use crate::ty::{self, BoundVar, InferConst, Ty, TyCtxt};
+use crate::ty::{self, BoundVar, Ty, TyCtxt};
 use crate::util::captures::Captures;
 
 impl<'tcx> InferCtxtBuilder<'tcx> {
@@ -493,10 +493,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
                     }
                 }
                 GenericArgKind::Const(result_value) => {
-                    if let ty::Const {
-                        val: ConstValue::Infer(InferConst::Canonical(debrujin, b)),
-                        ..
-                    } = result_value {
+                    if let ty::Const { val: ConstValue::Bound(debrujin, b), .. } = result_value {
                         // ...in which case we would set `canonical_vars[0]` to `Some(const X)`.
 
                         // We only allow a `ty::INNERMOST` index in substitutions.

src/librustc/infer/combine.rs

@@ -53,7 +53,7 @@ pub struct CombineFields<'infcx, 'tcx> {
     pub obligations: PredicateObligations<'tcx>,
 }
 
-#[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
+#[derive(Copy, Clone, Debug)]
 pub enum RelationDir {
     SubtypeOf, SupertypeOf, EqTo
 }

src/librustc/infer/freshen.rs

@@ -252,7 +252,7 @@ impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
                 return ct;
             }
 
-            ConstValue::Infer(ty::InferConst::Canonical(..)) |
+            ConstValue::Bound(..) |
             ConstValue::Placeholder(_) => {
                 bug!("unexpected const {:?}", ct)
             }

src/librustc/infer/mod.rs

@@ -407,7 +407,7 @@ pub enum RegionVariableOrigin {
     NLL(NLLRegionVariableOrigin),
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, Debug)]
 pub enum NLLRegionVariableOrigin {
     /// During NLL region processing, we create variables for free
     /// regions that we encounter in the function signature and

src/librustc/infer/nll_relate/mod.rs

@@ -27,12 +27,12 @@ use crate::ty::error::TypeError;
 use crate::ty::fold::{TypeFoldable, TypeVisitor};
 use crate::ty::relate::{self, Relate, RelateResult, TypeRelation};
 use crate::ty::subst::GenericArg;
-use crate::ty::{self, Ty, TyCtxt, InferConst};
+use crate::ty::{self, Ty, TyCtxt};
 use crate::mir::interpret::ConstValue;
 use rustc_data_structures::fx::FxHashMap;
 use std::fmt::Debug;
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(PartialEq)]
 pub enum NormalizationStrategy {
     Lazy,
     Eager,
@@ -618,7 +618,7 @@ where
         a: &'tcx ty::Const<'tcx>,
         b: &'tcx ty::Const<'tcx>,
     ) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>> {
-        if let ty::Const { val: ConstValue::Infer(InferConst::Canonical(_, _)), .. } = a {
+        if let ty::Const { val: ConstValue::Bound(..), .. } = a {
             // FIXME(const_generics): I'm unsure how this branch should actually be handled,
             // so this is probably not correct.
             self.infcx.super_combine_consts(self, a, b)
@@ -993,7 +993,7 @@ where
     ) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>> {
         debug!("TypeGeneralizer::consts(a={:?})", a);
 
-        if let ty::Const { val: ConstValue::Infer(InferConst::Canonical(_, _)), .. } = a {
+        if let ty::Const { val: ConstValue::Bound(..), .. } = a {
             bug!(
                 "unexpected inference variable encountered in NLL generalization: {:?}",
                 a

src/librustc/infer/region_constraints/mod.rs

@@ -116,7 +116,7 @@ pub struct RegionConstraintData<'tcx> {
 }
 
 /// Represents a constraint that influences the inference process.
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, PartialOrd, Ord)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug, PartialOrd, Ord)]
 pub enum Constraint<'tcx> {
     /// A region variable is a subregion of another.
     VarSubVar(RegionVid, RegionVid),

src/librustc/lib.rs

@@ -43,6 +43,7 @@
 #![feature(nll)]
 #![feature(non_exhaustive)]
 #![feature(optin_builtin_traits)]
+#![feature(option_expect_none)]
 #![feature(range_is_empty)]
 #![feature(slice_patterns)]
 #![feature(specialization)]

src/librustc/middle/cstore.rs

@@ -117,7 +117,7 @@ pub struct NativeLibrary {
     pub wasm_import_module: Option<Symbol>,
 }
 
-#[derive(Clone, Hash, RustcEncodable, RustcDecodable, HashStable)]
+#[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
 pub struct ForeignModule {
     pub foreign_items: Vec<DefId>,
     pub def_id: DefId,

src/librustc/middle/mem_categorization.rs

@@ -102,7 +102,7 @@ pub struct Upvar {
 }
 
 // different kinds of pointers:
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum PointerKind<'tcx> {
     /// `Box<T>`
     Unique,
@@ -116,7 +116,7 @@ pub enum PointerKind<'tcx> {
 
 // We use the term "interior" to mean "something reachable from the
 // base without a pointer dereference", e.g., a field
-#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Clone, PartialEq)]
 pub enum InteriorKind {
     InteriorField(FieldIndex),
     InteriorElement(InteriorOffsetKind),
@@ -139,13 +139,13 @@ impl Hash for FieldIndex {
     }
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, PartialEq)]
 pub enum InteriorOffsetKind {
     Index,   // e.g., `array_expr[index_expr]`
     Pattern, // e.g., `fn foo([_, a, _, _]: [A; 4]) { ... }`
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, Debug)]
 pub enum MutabilityCategory {
     McImmutable, // Immutable.
     McDeclared,  // Directly declared as mutable.

src/librustc/middle/stability.rs

@@ -25,7 +25,7 @@ use crate::util::nodemap::{FxHashSet, FxHashMap};
 use std::mem::replace;
 use std::cmp::Ordering;
 
-#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Copy, Debug, Eq, Hash)]
+#[derive(PartialEq, Clone, Copy, Debug)]
 pub enum StabilityLevel {
     Unstable,
     Stable,