cleanup

src/librustc_mir/borrow_check/type_check/mod.rs

@@ -649,7 +649,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
                 PlaceTy::from_ty(match base_ty.kind {
                     ty::Array(inner, _) => {
                         assert!(!from_end, "array subslices should not use from_end");
-                        tcx.mk_array(inner, (to - from) as u64)
+                        tcx.mk_array(inner, to - from)
                     }
                     ty::Slice(..) => {
                         assert!(from_end, "slice subslices should use from_end");

src/librustc_mir/interpret/place.rs

@@ -549,17 +549,17 @@ where
 
             ConstantIndex { offset, min_length, from_end } => {
                 let n = base.len(self)?;
-                if n < u64::from(min_length) {
+                if n < min_length {
                     // This can only be reached in ConstProp and non-rustc-MIR.
                     throw_ub!(BoundsCheckFailed { len: min_length.into(), index: n });
                 }
 
                 let index = if from_end {
                     assert!(0 < offset && offset <= min_length);
-                    n.checked_sub(u64::from(offset)).unwrap()
+                    n.checked_sub(offset).unwrap()
                 } else {
                     assert!(offset < min_length);
-                    u64::from(offset)
+                    offset
                 };
 
                 self.mplace_index(base, index)?

src/librustc_mir/util/aggregate.rs

@@ -4,6 +4,7 @@ use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_target::abi::VariantIdx;
 
 use std::iter::TrustedLen;
+use std::convert::TryFrom;
 
 /// Expand `lhs = Rvalue::Aggregate(kind, operands)` into assignments to the fields.
 ///

src/librustc_mir/util/elaborate_drops.rs

@@ -10,8 +10,6 @@ use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_target::abi::VariantIdx;
 use std::fmt;
 
-use std::convert::TryInto;
-
 /// The value of an inserted drop flag.
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 pub enum DropFlagState {
@@ -744,9 +742,6 @@ where
         let tcx = self.tcx();
 
         if let Some(size) = opt_size {
-            let size: u64 = size.try_into().unwrap_or_else(|_| {
-                bug!("move out check isn't implemented for array sizes bigger than u64::MAX");
-            });
             let fields: Vec<(Place<'tcx>, Option<D::Path>)> = (0..size)
                 .map(|i| {
                     (