Merge #1138

1138: Add L_DOLLAR and R_DOLLAR r=matklad a=edwin0cheng

As discussion in issue https://github.com/rust-analyzer/rust-analyzer/issues/1132 and PR #1125 , this PR add 2 `Syntax::Kind` : `L_DOLLAR` and `R_DOLLAR` for representing `Delimiter::None` in mbe and proc_marco. By design, It should not affect the final syntax tree, and will be discard in `TreeSink`.

My original idea is handling these 2 tokens case by case, but i found that they will appear in every place in the parser (imagine `tt` matcher). So this PR only handle it in `Parser::do_bump` and `Parser::start`, although It will not fix the `expr` matcher executing order problem in original idea.


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

1 files changed, 13 insertions, 2 deletions

diff --git a/crates/ra_mbe/src/subtree_parser.rs b/crates/ra_mbe/src/subtree_parser.rs
index ce39a40bb..13d5d2169 100644
--- a/crates/ra_mbe/src/subtree_parser.rs
+++ b/crates/ra_mbe/src/subtree_parser.rs
@@ -30,12 +30,23 @@ impl<'a> Parser<'a> {
         self.parse(ra_parser::parse_path)
     }
 
+    pub fn parse_expr(self) -> Option<tt::TokenTree> {
+        self.parse(ra_parser::parse_expr)
+    }
+
+    pub fn parse_ty(self) -> Option<tt::TokenTree> {
+        self.parse(ra_parser::parse_ty)
+    }
+
+    pub fn parse_pat(self) -> Option<tt::TokenTree> {
+        self.parse(ra_parser::parse_pat)
+    }
+
     fn parse<F>(self, f: F) -> Option<tt::TokenTree>
     where
         F: FnOnce(&dyn TokenSource, &mut dyn TreeSink),
     {
-        let mut src = SubtreeTokenSource::new(self.subtree);
-        src.start_from_nth(*self.cur_pos);
+        let mut src = SubtreeTokenSource::new(&self.subtree.token_trees[*self.cur_pos..]);
         let mut sink = OffsetTokenSink { token_pos: 0 };
 
         f(&src, &mut sink);