Auto merge of #6843 - Jarcho:match_on_same_arms_macro, r=Manishearth

Compare empty blocks for equality based on tokens

fixes: #1390

This only considers empty blocks for now, though we should also catch something like this:

```rust
match 0 {
    0 => {
        do_something();
        trace!(0);
        0
    }
    1 => {
        do_something();
        trace!(1);
        1
    }
    x => x,
}
```

As far as I can tell there aren't any negative effects on other lints. These blocks only happen to be the same for a given compilation, not all compilations.

changelog: Fix `match_on_same_arms` and others. Only consider empty blocks equal if the tokens contained are the same.

1 files changed, 1 insertions, 0 deletions

diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs
index 00455d4102f..0395079901c 100644
--- a/clippy_utils/src/lib.rs
+++ b/clippy_utils/src/lib.rs
@@ -14,6 +14,7 @@ extern crate rustc_errors;
 extern crate rustc_hir;
 extern crate rustc_hir_pretty;
 extern crate rustc_infer;
+extern crate rustc_lexer;
 extern crate rustc_lint;
 extern crate rustc_middle;
 extern crate rustc_mir;