compiler: fix few needless_pass_by_ref_mut clippy lints

warning: this argument is a mutable reference, but not used mutably
   --> compiler\rustc_builtin_macros\src\deriving\mod.rs:120:9
    |
120 |     cx: &mut ExtCtxt<'_>,
    |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
    --> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1573:13
     |
1573 |         cx: &mut ExtCtxt<'_>,
     |             ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
     |
     = 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
    --> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1556:13
     |
1556 |         cx: &mut ExtCtxt<'_>,
     |             ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
     |
     = 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
    --> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1463:13
     |
1463 |         cx: &mut ExtCtxt<'_>,
     |             ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
     |
     = 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
    --> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1433:36
     |
1433 |     fn summarise_struct(&self, cx: &mut ExtCtxt<'_>, struct_def: &VariantData) -> StaticFields {
     |                                    ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
     |
     = 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
   --> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:953:13
    |
953 |         cx: &mut ExtCtxt<'_>,
    |             ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
   --> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:932:13
    |
932 |         cx: &mut ExtCtxt<'_>,
    |             ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
   --> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:580:13
    |
580 |         cx: &mut ExtCtxt<'_>,
    |             ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
   --> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:989:13
    |
989 |         cx: &mut ExtCtxt<'_>,
    |             ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
  --> compiler\rustc_builtin_macros\src\deriving\clone.rs:97:9
   |
97 |     cx: &mut ExtCtxt<'_>,
   |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
   |
   = 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
  --> compiler\rustc_builtin_macros\src\deriving\cmp\eq.rs:52:9
   |
52 |     cx: &mut ExtCtxt<'_>,
   |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
   |
   = 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
  --> compiler\rustc_builtin_macros\src\deriving\hash.rs:50:9
   |
50 |     cx: &mut ExtCtxt<'_>,
   |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
   |
   = 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
   --> compiler\rustc_builtin_macros\src\deriving\encodable.rs:150:9
    |
150 |     cx: &mut ExtCtxt<'_>,
    |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
   --> compiler\rustc_builtin_macros\src\deriving\default.rs:176:9
    |
176 |     cx: &mut ExtCtxt<'_>,
    |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
   --> compiler\rustc_builtin_macros\src\deriving\default.rs:106:9
    |
106 |     cx: &mut ExtCtxt<'_>,
    |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
  --> compiler\rustc_builtin_macros\src\deriving\default.rs:57:9
   |
57 |     cx: &mut ExtCtxt<'_>,
   |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
   |
   = 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
  --> compiler\rustc_builtin_macros\src\deriving\default.rs:84:9
   |
84 |     cx: &mut ExtCtxt<'_>,
   |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
   |
   = 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
   --> compiler\rustc_builtin_macros\src\deriving\debug.rs:212:9
    |
212 |     cx: &mut ExtCtxt<'_>,
    |         ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
    |
    = 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
  --> compiler\rustc_builtin_macros\src\deriving\debug.rs:48:26
   |
48 | fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> BlockOrExpr {
   |                          ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut

0 files changed, 0 insertions, 0 deletions