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, 5 insertions, 5 deletions

diff --git a/crates/ra_mbe/src/mbe_expander/transcriber.rs b/crates/ra_mbe/src/mbe_expander/transcriber.rs
index ed094d5bb..f7636db11 100644
--- a/crates/ra_mbe/src/mbe_expander/transcriber.rs
+++ b/crates/ra_mbe/src/mbe_expander/transcriber.rs
@@ -50,7 +50,7 @@ pub(super) fn transcribe(
     template: &tt::Subtree,
     bindings: &Bindings,
 ) -> Result<tt::Subtree, ExpandError> {
-    assert!(template.delimiter == tt::Delimiter::None);
+    assert!(template.delimiter == None);
     let mut ctx = ExpandCtx { bindings: &bindings, nesting: Vec::new(), var_expanded: false };
     expand_subtree(&mut ctx, template)
 }
@@ -106,7 +106,7 @@ fn expand_var(ctx: &mut ExpandCtx, v: &SmolStr) -> Result<Fragment, ExpandError>
         // ```
         // We just treat it a normal tokens
         let tt = tt::Subtree {
-            delimiter: tt::Delimiter::None,
+            delimiter: None,
             token_trees: vec![
                 tt::Leaf::from(tt::Punct { char: '$', spacing: tt::Spacing::Alone }).into(),
                 tt::Leaf::from(tt::Ident { text: v.clone(), id: tt::TokenId::unspecified() })
@@ -147,7 +147,7 @@ fn expand_repeat(
     ctx.var_expanded = false;
 
     while let Ok(mut t) = expand_subtree(ctx, template) {
-        t.delimiter = tt::Delimiter::None;
+        t.delimiter = None;
         // if no var expanded in the child, we count it as a fail
         if !ctx.var_expanded {
             break;
@@ -212,7 +212,7 @@ fn expand_repeat(
 
     // Check if it is a single token subtree without any delimiter
     // e.g {Delimiter:None> ['>'] /Delimiter:None>}
-    let tt = tt::Subtree { delimiter: tt::Delimiter::None, token_trees: buf }.into();
+    let tt = tt::Subtree { delimiter: None, token_trees: buf }.into();
     Ok(Fragment::Tokens(tt))
 }
 
@@ -225,7 +225,7 @@ fn push_fragment(buf: &mut Vec<tt::TokenTree>, fragment: Fragment) {
 
 fn push_subtree(buf: &mut Vec<tt::TokenTree>, tt: tt::Subtree) {
     match tt.delimiter {
-        tt::Delimiter::None => buf.extend(tt.token_trees),
+        None => buf.extend(tt.token_trees),
         _ => buf.push(tt.into()),
     }
 }