rustc_back: remove slice module in favor of std::slice::from_ref.

src/Cargo.lock

@@ -1687,7 +1687,6 @@ dependencies = [
  "graphviz 0.0.0",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
- "rustc_back 0.0.0",
  "rustc_errors 0.0.0",
  "rustc_mir 0.0.0",
  "syntax 0.0.0",
@@ -1701,7 +1700,6 @@ dependencies = [
  "arena 0.0.0",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
- "rustc_back 0.0.0",
  "rustc_const_math 0.0.0",
  "rustc_data_structures 0.0.0",
  "rustc_errors 0.0.0",
@@ -1999,7 +1997,6 @@ dependencies = [
  "fmt_macros 0.0.0",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
- "rustc_back 0.0.0",
  "rustc_const_math 0.0.0",
  "rustc_data_structures 0.0.0",
  "rustc_errors 0.0.0",

src/librustc/lib.rs

@@ -46,6 +46,7 @@
 #![feature(const_fn)]
 #![feature(core_intrinsics)]
 #![feature(drain_filter)]
+#![feature(from_ref)]
 #![feature(i128)]
 #![feature(i128_type)]
 #![feature(inclusive_range)]

src/librustc/lint/context.rs

@@ -26,7 +26,7 @@
 
 use self::TargetLint::*;
 
-use rustc_back::slice;
+use std::slice;
 use lint::{EarlyLintPassObject, LateLintPassObject};
 use lint::{Level, Lint, LintId, LintPass, LintBuffer};
 use lint::levels::{LintLevelSets, LintLevelsBuilder};
@@ -308,7 +308,7 @@ impl LintStore {
                     Some(ids) => CheckLintNameResult::Ok(&ids.0),
                 }
             }
-            Some(&Id(ref id)) => CheckLintNameResult::Ok(slice::ref_slice(id)),
+            Some(&Id(ref id)) => CheckLintNameResult::Ok(slice::from_ref(id)),
         }
     }
 }

src/librustc/middle/resolve_lifetime.rs

@@ -31,7 +31,7 @@ use syntax_pos::Span;
 use errors::DiagnosticBuilder;
 use util::common::ErrorReported;
 use util::nodemap::{NodeMap, NodeSet, FxHashSet, FxHashMap, DefIdMap};
-use rustc_back::slice;
+use std::slice;
 
 use hir;
 use hir::intravisit::{self, Visitor, NestedVisitorMap};
@@ -530,7 +530,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
 
     fn visit_lifetime(&mut self, lifetime_ref: &'tcx hir::Lifetime) {
         if lifetime_ref.is_elided() {
-            self.resolve_elided_lifetimes(slice::ref_slice(lifetime_ref));
+            self.resolve_elided_lifetimes(slice::from_ref(lifetime_ref));
             return;
         }
         if lifetime_ref.is_static() {

src/librustc/mir/mod.rs

@@ -25,7 +25,7 @@ use ty::subst::{Subst, Substs};
 use ty::{self, AdtDef, ClosureSubsts, Region, Ty, TyCtxt, GeneratorInterior};
 use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 use util::ppaux;
-use rustc_back::slice;
+use std::slice;
 use hir::{self, InlineAsm};
 use std::ascii;
 use std::borrow::{Cow};
@@ -754,28 +754,28 @@ impl<'tcx> TerminatorKind<'tcx> {
     pub fn successors(&self) -> Cow<[BasicBlock]> {
         use self::TerminatorKind::*;
         match *self {
-            Goto { target: ref b } => slice::ref_slice(b).into_cow(),
+            Goto { target: ref b } => slice::from_ref(b).into_cow(),
             SwitchInt { targets: ref b, .. } => b[..].into_cow(),
             Resume | GeneratorDrop => (&[]).into_cow(),
             Return => (&[]).into_cow(),
             Unreachable => (&[]).into_cow(),
             Call { destination: Some((_, t)), cleanup: Some(c), .. } => vec![t, c].into_cow(),
             Call { destination: Some((_, ref t)), cleanup: None, .. } =>
-                slice::ref_slice(t).into_cow(),
+                slice::from_ref(t).into_cow(),
-            Call { destination: None, cleanup: Some(ref c), .. } => slice::ref_slice(c).into_cow(),
+            Call { destination: None, cleanup: Some(ref c), .. } => slice::from_ref(c).into_cow(),
             Call { destination: None, cleanup: None, .. } => (&[]).into_cow(),
             Yield { resume: t, drop: Some(c), .. } => vec![t, c].into_cow(),
-            Yield { resume: ref t, drop: None, .. } => slice::ref_slice(t).into_cow(),
+            Yield { resume: ref t, drop: None, .. } => slice::from_ref(t).into_cow(),
             DropAndReplace { target, unwind: Some(unwind), .. } |
             Drop { target, unwind: Some(unwind), .. } => {
                 vec![target, unwind].into_cow()
             }
             DropAndReplace { ref target, unwind: None, .. } |
             Drop { ref target, unwind: None, .. } => {
-                slice::ref_slice(target).into_cow()
+                slice::from_ref(target).into_cow()
             }
             Assert { target, cleanup: Some(unwind), .. } => vec![target, unwind].into_cow(),
-            Assert { ref target, .. } => slice::ref_slice(target).into_cow(),
+            Assert { ref target, .. } => slice::from_ref(target).into_cow(),
             FalseEdges { ref real_target, ref imaginary_targets } => {
                 let mut s = vec![*real_target];
                 s.extend_from_slice(imaginary_targets);

src/librustc_back/lib.rs

@@ -40,7 +40,6 @@ extern crate serialize as rustc_serialize; // used by deriving
 
 pub mod tempdir;
 pub mod target;
-pub mod slice;
 pub mod dynamic_lib;
 
 use std::str::FromStr;

src/librustc_back/slice.rs

@@ -1,19 +0,0 @@
-// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use std::mem;
-
-pub fn ref_slice<T>(ptr: &T) -> &[T; 1] {
-    unsafe { mem::transmute(ptr) }
-}
-
-pub fn mut_ref_slice<T>(ptr: &mut T) -> &mut [T; 1] {
-    unsafe { mem::transmute(ptr) }
-}

src/librustc_borrowck/Cargo.toml

@@ -15,6 +15,5 @@ syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
 graphviz = { path = "../libgraphviz" }
 rustc = { path = "../librustc" }
-rustc_back = { path = "../librustc_back" }
 rustc_mir = { path = "../librustc_mir" }
 rustc_errors = { path = "../librustc_errors" }

src/librustc_borrowck/borrowck/unused.rs

@@ -13,7 +13,7 @@ use rustc::hir::{self, HirId};
 use rustc::lint::builtin::UNUSED_MUT;
 use rustc::ty;
 use rustc::util::nodemap::{FxHashMap, FxHashSet};
-use rustc_back::slice;
+use std::slice;
 use syntax::ptr::P;
 
 use borrowck::BorrowckCtxt;
@@ -26,7 +26,7 @@ pub fn check<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>, body: &'tcx hir::Body) {
     }.visit_expr(&body.value);
     let mut cx = UnusedMutCx { bccx, used_mut };
     for arg in body.arguments.iter() {
-        cx.check_unused_mut_pat(slice::ref_slice(&arg.pat));
+        cx.check_unused_mut_pat(slice::from_ref(&arg.pat));
     }
     cx.visit_expr(&body.value);
 }
@@ -101,7 +101,7 @@ impl<'a, 'tcx> Visitor<'tcx> for UnusedMutCx<'a, 'tcx> {
     }
 
     fn visit_local(&mut self, local: &hir::Local) {
-        self.check_unused_mut_pat(slice::ref_slice(&local.pat));
+        self.check_unused_mut_pat(slice::from_ref(&local.pat));
     }
 }
 

src/librustc_borrowck/lib.rs

@@ -15,6 +15,7 @@
 
 #![allow(non_camel_case_types)]
 
+#![feature(from_ref)]
 #![feature(match_default_bindings)]
 #![feature(quote)]
 
@@ -22,7 +23,6 @@
 extern crate syntax;
 extern crate syntax_pos;
 extern crate rustc_errors as errors;
-extern crate rustc_back;
 
 // for "clarity", rename the graphviz crate to dot; graphviz within `borrowck`
 // refers to the borrowck-specific graphviz adapter traits.

src/librustc_const_eval/Cargo.toml

@@ -12,7 +12,6 @@ crate-type = ["dylib"]
 arena = { path = "../libarena" }
 log = "0.3"
 rustc = { path = "../librustc" }
-rustc_back = { path = "../librustc_back" }
 rustc_const_math = { path = "../librustc_const_math" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }

src/librustc_const_eval/check_match.rs

@@ -31,7 +31,7 @@ use rustc::hir::def_id::DefId;
 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
 use rustc::hir::{self, Pat, PatKind};
 
-use rustc_back::slice;
+use std::slice;
 
 use syntax::ast;
 use syntax::ptr::P;
@@ -114,7 +114,7 @@ impl<'a, 'tcx> Visitor<'tcx> for MatchVisitor<'a, 'tcx> {
         });
 
         // Check legality of move bindings and `@` patterns.
-        self.check_patterns(false, slice::ref_slice(&loc.pat));
+        self.check_patterns(false, slice::from_ref(&loc.pat));
     }
 
     fn visit_body(&mut self, body: &'tcx hir::Body) {
@@ -122,7 +122,7 @@ impl<'a, 'tcx> Visitor<'tcx> for MatchVisitor<'a, 'tcx> {
 
         for arg in &body.arguments {
             self.check_irrefutable(&arg.pat, "function argument");
-            self.check_patterns(false, slice::ref_slice(&arg.pat));
+            self.check_patterns(false, slice::from_ref(&arg.pat));
         }
     }
 }

src/librustc_const_eval/lib.rs

@@ -24,12 +24,12 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(i128_type)]
+#![feature(from_ref)]
 
 extern crate arena;
 #[macro_use] extern crate syntax;
 #[macro_use] extern crate log;
 #[macro_use] extern crate rustc;
-extern crate rustc_back;
 extern crate rustc_const_math;
 extern crate rustc_data_structures;
 extern crate rustc_errors;

src/librustc_typeck/Cargo.toml

@@ -15,7 +15,6 @@ syntax = { path = "../libsyntax" }
 arena = { path = "../libarena" }
 fmt_macros = { path = "../libfmt_macros" }
 rustc = { path = "../librustc" }
-rustc_back = { path = "../librustc_back" }
 rustc_const_math = { path = "../librustc_const_math" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_platform_intrinsics = { path = "../librustc_platform_intrinsics" }

src/librustc_typeck/astconv.rs

@@ -23,7 +23,7 @@ use rustc::ty::subst::{Kind, Subst, Substs};
 use rustc::traits;
 use rustc::ty::{self, RegionKind, Ty, TyCtxt, ToPredicate, TypeFoldable};
 use rustc::ty::wf::object_region_bounds;
-use rustc_back::slice;
+use std::slice;
 use require_c_abi_if_variadic;
 use util::common::ErrorReported;
 use util::nodemap::FxHashSet;
@@ -782,7 +782,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
 
         debug!("associated_path_def_to_ty: {:?}::{}", ty, assoc_name);
 
-        self.prohibit_type_params(slice::ref_slice(item_segment));
+        self.prohibit_type_params(slice::from_ref(item_segment));
 
         // Find the type of the associated item, and the trait where the associated
         // item is declared.
@@ -859,7 +859,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
         let tcx = self.tcx();
         let trait_def_id = tcx.parent_def_id(item_def_id).unwrap();
 
-        self.prohibit_type_params(slice::ref_slice(item_segment));
+        self.prohibit_type_params(slice::from_ref(item_segment));
 
         let self_ty = if let Some(ty) = opt_self_ty {
             ty

src/librustc_typeck/check/mod.rs

@@ -87,7 +87,7 @@ use self::TupleArgumentsFlag::*;
 use astconv::AstConv;
 use hir::def::{Def, CtorKind};
 use hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
-use rustc_back::slice::ref_slice;
+use std::slice;
 use namespace::Namespace;
 use rustc::infer::{self, InferCtxt, InferOk, RegionVariableOrigin};
 use rustc::infer::type_variable::{TypeVariableOrigin};
@@ -130,7 +130,6 @@ use rustc::hir::itemlikevisit::ItemLikeVisitor;
 use rustc::hir::map::Node;
 use rustc::hir::{self, PatKind};
 use rustc::middle::lang_items;
-use rustc_back::slice;
 use rustc_const_math::ConstInt;
 
 mod autoderef;
@@ -4168,7 +4167,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         if let Some(cached_def) = self.tables.borrow().type_dependent_defs().get(hir_id) {
             // Return directly on cache hit. This is useful to avoid doubly reporting
             // errors with default match binding modes. See #44614.
-            return (*cached_def, Some(ty), slice::ref_slice(&**item_segment))
+            return (*cached_def, Some(ty), slice::from_ref(&**item_segment))
         }
         let item_name = item_segment.name;
         let def = match self.resolve_ufcs(span, item_name, ty, node_id) {
@@ -4187,7 +4186,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
         // Write back the new resolution.
         self.tables.borrow_mut().type_dependent_defs_mut().insert(hir_id, def);
-        (def, Some(ty), slice::ref_slice(&**item_segment))
+        (def, Some(ty), slice::from_ref(&**item_segment))
     }
 
     pub fn check_decl_initializer(&self,
@@ -4325,7 +4324,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             CoerceMany::new(coerce_to_ty)
         } else {
             let tail_expr: &[P<hir::Expr>] = match tail_expr {
-                Some(e) => ref_slice(e),
+                Some(e) => slice::from_ref(e),
                 None => &[],
             };
             CoerceMany::with_coercion_sites(coerce_to_ty, tail_expr)

src/librustc_typeck/lib.rs

@@ -77,6 +77,7 @@ This API is completely unstable and subject to change.
 #![feature(box_syntax)]
 #![feature(crate_visibility_modifier)]
 #![feature(conservative_impl_trait)]
+#![feature(from_ref)]
 #![feature(match_default_bindings)]
 #![feature(never_type)]
 #![feature(quote)]
@@ -90,7 +91,6 @@ extern crate syntax_pos;
 extern crate arena;
 #[macro_use] extern crate rustc;
 extern crate rustc_platform_intrinsics as intrinsics;
-extern crate rustc_back;
 extern crate rustc_const_math;
 extern crate rustc_data_structures;
 extern crate rustc_errors as errors;