Merge #2551

2551: Refactor tt::Subtree delimiter r=matklad a=edwin0cheng

Refactor to : 
```
#[derive(Debug, Clone, PartialEq, Eq, Hash, Default)]
pub struct Subtree {
    pub delimiter: Option<Delimiter>,
    pub token_trees: Vec<TokenTree>,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum Delimiter {
    Parenthesis,
    Brace,
    Bracket,
}
```

Co-authored-by: Edwin Cheng <[email protected]>

1 files changed, 2 insertions, 2 deletions

diff --git a/crates/ra_mbe/src/lib.rs b/crates/ra_mbe/src/lib.rs
index bbddebe67..0d2d43bef 100644
--- a/crates/ra_mbe/src/lib.rs
+++ b/crates/ra_mbe/src/lib.rs
@@ -159,14 +159,14 @@ impl Rule {
             .expect_subtree()
             .map_err(|()| ParseError::Expected("expected subtree".to_string()))?
             .clone();
-        lhs.delimiter = tt::Delimiter::None;
+        lhs.delimiter = None;
         src.expect_char('=').map_err(|()| ParseError::Expected("expected `=`".to_string()))?;
         src.expect_char('>').map_err(|()| ParseError::Expected("expected `>`".to_string()))?;
         let mut rhs = src
             .expect_subtree()
             .map_err(|()| ParseError::Expected("expected subtree".to_string()))?
             .clone();
-        rhs.delimiter = tt::Delimiter::None;
+        rhs.delimiter = None;
         Ok(crate::Rule { lhs, rhs })
     }
 }