Fixed nits raised in review.

Author: Alexander Regueiro

src/bin/miri.rs

@@ -178,7 +178,7 @@ fn find_sysroot() -> String {
         _ => {
             option_env!("RUST_SYSROOT")
                 .expect(
-                    "could not find sysroot. either set `MIRI_SYSROOT` at run-time, or at \
+                    "could not find sysroot. Either set `MIRI_SYSROOT` at run-time, or at \
                      build-time specify `RUST_SYSROOT` env var or use rustup or multirust",
                 )
                 .to_owned()

src/lib.rs

@@ -39,8 +39,7 @@ pub use crate::operator::EvalContextExt as OperatorEvalContextExt;
 pub use crate::intrinsic::EvalContextExt as IntrinsicEvalContextExt;
 pub use crate::tls::{EvalContextExt as TlsEvalContextExt, TlsData};
 use crate::range_map::RangeMap;
-// FIXME: rustc bug, issue <https://github.com/rust-lang/rust/issues/53682>.
-#[allow(unused_imports)]
+#[allow(unused_imports)] // FIXME: rustc bug, issue <https://github.com/rust-lang/rust/issues/53682>.
 pub use crate::helpers::{EvalContextExt as HelpersEvalContextExt};
 use crate::mono_hash_map::MonoHashMap;
 pub use crate::stacked_borrows::{EvalContextExt as StackedBorEvalContextExt};
@@ -129,7 +128,7 @@ pub fn create_ecx<'a, 'mir: 'a, 'tcx: 'mir>(
     let dest = ecx.eval_place(&mir::Place::Local(args.next().unwrap()))?;
     let argc = Scalar::from_uint(config.args.len() as u128, dest.layout.size);
     ecx.write_scalar(argc, dest)?;
-    // Store argc for macOS: `_NSGetArgc`.
+    // Store argc for macOS's `_NSGetArgc`.
     {
         let argc_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
         ecx.write_scalar(argc, argc_place.into())?;

src/range_map.rs

@@ -14,8 +14,9 @@ use rustc::ty::layout::Size;
 
 #[derive(Clone, Debug)]
 struct Elem<T> {
-    /// The range covered by this element, never empty.
+    /// The range covered by this element; never empty.
     range: ops::Range<u64>,
+    /// The data stored for this element.
     data: T,
 }
 #[derive(Clone, Debug)]
@@ -49,11 +50,11 @@ impl<T> RangeMap<T> {
             let candidate = left.checked_add(right).unwrap() / 2;
             let elem = &self.v[candidate];
             if offset < elem.range.start {
-                // we are too far right (offset is further left)
+                // We are too far right (offset is further left).
                 debug_assert!(candidate < right); // we are making progress
                 right = candidate;
             } else if offset >= elem.range.end {
-                // we are too far left (offset is further right)
+                // We are too far left (offset is further right).
                 debug_assert!(candidate >= left); // we are making progress
                 left = candidate+1;
             } else {