Resolve precedence clippy lint

    warning: operator precedence can trip the unwary
       --> src/read.rs:963:18
        |
    963 |         let n = (((n1 - 0xD800) as u32) << 10 | (n2 - 0xDC00) as u32) + 0x1_0000;
        |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(((n1 - 0xD800) as u32) << 10) | (n2 - 0xDC00) as u32`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
        = note: `-W clippy::precedence` implied by `-W clippy::all`
        = help: to override `-W clippy::all` add `#[allow(clippy::precedence)]`

    warning: operator precedence can trip the unwary
       --> src/read.rs:991:28
        |
    991 |                 ptr.write((n >> 6 & 0b0001_1111) as u8 | 0b1100_0000);
        |                            ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(n >> 6) & 0b0001_1111`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence

    warning: operator precedence can trip the unwary
       --> src/read.rs:995:28
        |
    995 |                 ptr.write((n >> 12 & 0b0000_1111) as u8 | 0b1110_0000);
        |                            ^^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(n >> 12) & 0b0000_1111`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence

    warning: operator precedence can trip the unwary
       --> src/read.rs:996:35
        |
    996 |                 ptr.add(1).write((n >> 6 & 0b0011_1111) as u8 | 0b1000_0000);
        |                                   ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(n >> 6) & 0b0011_1111`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence

    warning: operator precedence can trip the unwary
        --> src/read.rs:1000:28
         |
    1000 |                 ptr.write((n >> 18 & 0b0000_0111) as u8 | 0b1111_0000);
         |                            ^^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(n >> 18) & 0b0000_0111`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence

    warning: operator precedence can trip the unwary
        --> src/read.rs:1002:29
         |
    1002 |                     .write((n >> 12 & 0b0011_1111) as u8 | 0b1000_0000);
         |                             ^^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(n >> 12) & 0b0011_1111`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence

    warning: operator precedence can trip the unwary
        --> src/read.rs:1003:35
         |
    1003 |                 ptr.add(2).write((n >> 6 & 0b0011_1111) as u8 | 0b1000_0000);
         |                                   ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(n >> 6) & 0b0011_1111`
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence

Author: dtolnay

src/read.rs

@@ -960,7 +960,7 @@ fn parse_unicode_escape<'de, R: Read<'de>>(
 
         // This value is in range U+10000..=U+10FFFF, which is always a valid
         // codepoint.
-        let n = (((n1 - 0xD800) as u32) << 10 | (n2 - 0xDC00) as u32) + 0x1_0000;
+        let n = ((((n1 - 0xD800) as u32) << 10) | (n2 - 0xDC00) as u32) + 0x1_0000;
         push_wtf8_codepoint(n, scratch);
         return Ok(());
     }
@@ -988,19 +988,21 @@ fn push_wtf8_codepoint(n: u32, scratch: &mut Vec<u8>) {
         let encoded_len = match n {
             0..=0x7F => unreachable!(),
             0x80..=0x7FF => {
-                ptr.write((n >> 6 & 0b0001_1111) as u8 | 0b1100_0000);
+                ptr.write(((n >> 6) & 0b0001_1111) as u8 | 0b1100_0000);
                 2
             }
             0x800..=0xFFFF => {
-                ptr.write((n >> 12 & 0b0000_1111) as u8 | 0b1110_0000);
-                ptr.add(1).write((n >> 6 & 0b0011_1111) as u8 | 0b1000_0000);
+                ptr.write(((n >> 12) & 0b0000_1111) as u8 | 0b1110_0000);
+                ptr.add(1)
+                    .write(((n >> 6) & 0b0011_1111) as u8 | 0b1000_0000);
                 3
             }
             0x1_0000..=0x10_FFFF => {
-                ptr.write((n >> 18 & 0b0000_0111) as u8 | 0b1111_0000);
+                ptr.write(((n >> 18) & 0b0000_0111) as u8 | 0b1111_0000);
                 ptr.add(1)
-                    .write((n >> 12 & 0b0011_1111) as u8 | 0b1000_0000);
-                ptr.add(2).write((n >> 6 & 0b0011_1111) as u8 | 0b1000_0000);
+                    .write(((n >> 12) & 0b0011_1111) as u8 | 0b1000_0000);
+                ptr.add(2)
+                    .write(((n >> 6) & 0b0011_1111) as u8 | 0b1000_0000);
                 4
             }
             0x11_0000.. => unreachable!(),