Add vis matcher

crates/ra_mbe/src/lib.rs

@@ -809,4 +809,16 @@ MACRO_ITEMS@[0; 40)
         );
         assert_expansion(&rules, r#"foo!(u8 0)"#, r#"const VALUE: u8 = 0;"#);
     }
+
+    #[test]
+    fn test_vis() {
+        let rules = create_rules(
+            r#"
+        macro_rules! foo {
+              ($ vis:vis $ name:ident) => { $ vis fn $ name() {}};
+        }
+"#,
+        );
+        assert_expansion(&rules, r#"foo!(pub foo);"#, r#"pub fn foo() {}"#);
+    }
 }

crates/ra_mbe/src/mbe_expander.rs

@@ -193,6 +193,10 @@ fn match_lhs(pattern: &crate::Subtree, input: &mut TtCursor) -> Result<Bindings,
                                 Binding::Simple(tt::Leaf::from(literal).into()),
                             );
                         }
+                        "vis" => {
+                            let vis = input.eat_vis().ok_or(ExpandError::UnexpectedToken)?.clone();
+                            res.inner.insert(text.clone(), Binding::Simple(vis.into()));
+                        }
 
                         _ => return Err(ExpandError::UnexpectedToken),
                     }

crates/ra_mbe/src/subtree_parser.rs

@@ -58,6 +58,10 @@ impl<'a> Parser<'a> {
         self.parse(ra_parser::parse_item)
     }
 
+    pub fn parse_vis(self) -> Option<tt::TokenTree> {
+        self.parse(ra_parser::parse_vis)
+    }
+
     fn parse<F>(self, f: F) -> Option<tt::TokenTree>
     where
         F: FnOnce(&dyn TokenSource, &mut dyn TreeSink),

crates/ra_mbe/src/tt_cursor.rs

@@ -137,6 +137,11 @@ impl<'a> TtCursor<'a> {
         self.eat_ident().cloned().map(|ident| tt::Leaf::from(ident).into())
     }
 
+    pub(crate) fn eat_vis(&mut self) -> Option<tt::TokenTree> {
+        let parser = Parser::new(&mut self.pos, self.subtree);
+        parser.parse_vis()
+    }
+
     pub(crate) fn expect_char(&mut self, char: char) -> Result<(), ParseError> {
         if self.at_char(char) {
             self.bump();