Replace usages of ..i + 1 ranges with ..=i.

src/libstd/collections/hash/map.rs

@@ -3610,7 +3610,7 @@ mod test_map {
             for i in 1..1001 {
                 assert!(m.insert(i, i).is_none());
 
-                for j in 1..i + 1 {
+                for j in 1..=i {
                     let r = m.get(&j);
                     assert_eq!(r, Some(&j));
                 }
@@ -3629,7 +3629,7 @@ mod test_map {
             for i in 1..1001 {
                 assert!(m.remove(&i).is_some());
 
-                for j in 1..i + 1 {
+                for j in 1..=i {
                     assert!(!m.contains_key(&j));
                 }
 

src/libstd/io/buffered.rs

@@ -918,7 +918,7 @@ impl<W: Write> Write for LineWriter<W> {
         // some data then we *must* report that we wrote that data, so future
         // errors are ignored. We set our internal `need_flush` flag, though, in
         // case flushing fails and we need to try it first next time.
-        let n = self.inner.write(&buf[..i + 1])?;
+        let n = self.inner.write(&buf[..=i])?;
         self.need_flush = true;
         if self.flush().is_err() || n != i + 1 {
             return Ok(n)

src/libstd/io/mod.rs

@@ -1261,7 +1261,7 @@ fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
             };
             match memchr::memchr(delim, available) {
                 Some(i) => {
-                    buf.extend_from_slice(&available[..i + 1]);
+                    buf.extend_from_slice(&available[..=i]);
                     (true, i + 1)
                 }
                 None => {

src/libstd/sys/windows/process.rs

@@ -487,7 +487,7 @@ fn make_command_line(prog: &OsStr, args: &[OsString]) -> io::Result<Vec<u16>> {
             } else {
                 if x == '"' as u16 {
                     // Add n+1 backslashes to total 2n+1 before internal '"'.
-                    cmd.extend((0..(backslashes + 1)).map(|_| '\\' as u16));
+                    cmd.extend((0..=backslashes).map(|_| '\\' as u16));
                 }
                 backslashes = 0;
             }