warning: this expression creates a reference which is immediately dereferenced by the compiler
    --> src/xls.rs:1003:42
     |
1003 |                     .map_or("#REF", |sh| &sh);
     |                                          ^^^ help: change this to: `sh`
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
     = note: `#[warn(clippy::needless_borrow)]` on by default

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:610:53
    |
610 | fn parse_short_string(r: &mut Record<'_>, encoding: &mut XlsEncoding) -> Result<String, XlsError> {
    |                                                     ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
    = note: `#[warn(clippy::needless_pass_by_ref_mut)]` on by default

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:627:37
    |
627 | fn parse_string(r: &[u8], encoding: &mut XlsEncoding) -> Result<String, XlsError> {
    |                                     ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:725:16
    |
725 | fn parse_xf(r: &mut Record<'_>) -> Result<u16, XlsError> {
    |                ^^^^^^^^^^^^^^^ help: consider changing to: `&Record<'_>`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:742:15
    |
742 |     encoding: &mut XlsEncoding,
    |               ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:816:15
    |
816 |     encoding: &mut XlsEncoding,
    |               ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:839:15
    |
839 |     encoding: &mut XlsEncoding,
    |               ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:841:10
    |
841 |     len: &mut usize,
    |          ^^^^^^^^^^ help: consider changing to: `&usize`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:463:15
    |
463 |     encoding: &mut XlsEncoding,
    |               ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
    = note: `#[warn(clippy::needless_pass_by_ref_mut)]` on by default

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:768:15
    |
768 |     encoding: &mut XlsEncoding,
    |               ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:985:15
    |
985 |     encoding: &mut XlsEncoding,
    |               ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

warning: you don't need to add `&` to all patterns
    --> src/xls.rs:1304:5
     |
1304 | /     match r {
1305 | |         &[0x00, .., 0xFF, 0xFF] => Ok(None), // String, value should be in next record
1306 | |         &[0x01, _, b, .., 0xFF, 0xFF] => Ok(Some(DataType::Bool(b != 0))),
1307 | |         &[0x02, _, e, .., 0xFF, 0xFF] => parse_err(e).map(Some),
...    |
1312 | |         _ => Ok(Some(DataType::Float(read_f64(r)))),
1313 | |     }
     | |_____^
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#match_ref_pats
     = note: `#[warn(clippy::match_ref_pats)]` on by default
help: instead of prefixing all patterns with `&`, you can dereference the expression
     |
1304 ~     match *r {
1305 ~         [0x00, .., 0xFF, 0xFF] => Ok(None), // String, value should be in next record
1306 ~         [0x01, _, b, .., 0xFF, 0xFF] => Ok(Some(DataType::Bool(b != 0))),
1307 ~         [0x02, _, e, .., 0xFF, 0xFF] => parse_err(e).map(Some),
1308 ~         [e, .., 0xFF, 0xFF] => Err(XlsError::Unrecognized {

warning: the function `parse_format` doesn't need a mutable reference
   --> src/xls.rs:292:66
    |
292 |                         let (idx, format) = parse_format(&mut r, &mut encoding)?;
    |                                                                  ^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed
    = note: `#[warn(clippy::unnecessary_mut_passed)]` on by default

warning: the function `parse_xf` doesn't need a mutable reference
   --> src/xls.rs:297:43
    |
297 |                         xfs.push(parse_xf(&mut r)?);
    |                                           ^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed

warning: the function `parse_sheet_name` doesn't need a mutable reference
   --> src/xls.rs:301:68
    |
301 |                         let (pos, name) = parse_sheet_name(&mut r, &mut encoding)?;
    |                                                                    ^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed

warning: the function `read_unicode_string_no_cch` doesn't need a mutable reference
   --> src/xls.rs:311:29
    |
311 | ...                   &mut encoding,
    |                       ^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed

warning: the function `read_unicode_string_no_cch` doesn't need a mutable reference
   --> src/xls.rs:313:29
    |
313 | ...                   &mut cch,
    |                       ^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed

warning: the function `parse_sst` doesn't need a mutable reference
   --> src/xls.rs:329:59
    |
329 |                     0x00FC => strings = parse_sst(&mut r, &mut encoding)?, // SST
    |                                                           ^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed
    = note: `#[warn(clippy::unnecessary_mut_passed)]` on by default

warning: the function `parse_string` doesn't need a mutable reference
   --> src/xls.rs:396:73
    |
396 |                         let val = DataType::String(parse_string(r.data, &mut encoding)?);
    |                                                                         ^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed

warning: the function `parse_formula` doesn't need a mutable reference
   --> src/xls.rs:425:29
    |
425 | ...                   &mut encoding,
    |                       ^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed

warning: the function `read_unicode_string_no_cch` doesn't need a mutable reference
    --> src/xls.rs:1104:66
     |
1104 |                 read_unicode_string_no_cch(encoding, &rgce[1..], &mut cch, &mut formula);
     |                                                                  ^^^^^^^^
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed

warning: this argument is a mutable reference, but not used mutably
   --> src/xls.rs:704:44
    |
704 | fn parse_sst(r: &mut Record<'_>, encoding: &mut XlsEncoding) -> Result<Vec<String>, XlsError> {
    |                                            ^^^^^^^^^^^^^^^^ help: consider changing to: `&XlsEncoding`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
    = note: `#[warn(clippy::needless_pass_by_ref_mut)]` on by default

warning: this `impl` can be derived
  --> src/datatype.rs:42:1
   |
42 | / impl Default for DataType {
43 | |     fn default() -> DataType {
44 | |         DataType::Empty
45 | |     }
46 | | }
   | |_^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#derivable_impls
   = note: `#[warn(clippy::derivable_impls)]` on by default
   = help: remove the manual implementation...
help: ...and instead derive it...
   |
19 + #[derive(Default)]
20 | pub enum DataType {
   |
help: ...and mark the default variant
   |
39 ~     #[default]
40 ~     Empty,

is-terminal is a dependency of env-logger