G: use trees

2 files changed, 71 insertions, 7 deletions

diff --git a/src/parser/event_parser/grammar/items.rs b/src/parser/event_parser/grammar/items.rs
index f7310c09a..2f64111ab 100644
--- a/src/parser/event_parser/grammar/items.rs
+++ b/src/parser/event_parser/grammar/items.rs
@@ -74,9 +74,63 @@ fn mod_item(p: &mut Parser) {
     p.curly_block(mod_contents);
 }
 
+pub(super) fn is_use_tree_start(kind: SyntaxKind) -> bool {
+    kind == STAR || kind == L_CURLY
+}
+
 fn use_item(p: &mut Parser) {
-    paths::use_path(p);
+    use_tree(p);
     p.expect(SEMI);
+
+    fn use_tree(p: &mut Parser) -> bool{
+        if node_if(p, STAR, USE_TREE, |_| ()) {
+            return true
+        }
+        if node_if(p, [COLONCOLON, STAR], USE_TREE, |_| ()) {
+           return true
+        }
+        if [COLONCOLON, L_CURLY].is_ahead(p) || L_CURLY.is_ahead(p) {
+            node(p, USE_TREE, |p| {
+                p.eat(COLONCOLON);
+                p.curly_block(|p| {
+                    comma_list(p, EOF, use_tree);
+                });
+            });
+            return true;
+        }
+        if paths::is_path_start(p) {
+            node(p, USE_TREE, |p| {
+                paths::use_path(p);
+                match p.current() {
+                    AS_KW => {
+                        alias(p);
+                    }
+                    COLONCOLON => {
+                        p.bump();
+                        match p.current() {
+                            STAR => {
+                                p.bump();
+                            }
+                            L_CURLY => {
+                                p.curly_block(|p| {
+                                    comma_list(p, EOF, use_tree);
+                                });
+                            }
+                            _ => {
+                                // is this unreachable?
+                                p.error()
+                                    .message("expected `{` or `*`")
+                                    .emit();
+                            }
+                        }
+                    }
+                    _ => (),
+                }
+            });
+            return true;
+        }
+        false
+    }
 }
 
 fn struct_field(p: &mut Parser) -> bool {
diff --git a/src/parser/event_parser/grammar/paths.rs b/src/parser/event_parser/grammar/paths.rs
index d6887a9ba..62d1a3bb2 100644
--- a/src/parser/event_parser/grammar/paths.rs
+++ b/src/parser/event_parser/grammar/paths.rs
@@ -1,7 +1,11 @@
 use super::*;
 
+pub (crate) fn is_path_start(p: &Parser) -> bool {
+    AnyOf(&[IDENT, SELF_KW, SUPER_KW, COLONCOLON]).is_ahead(p)
+}
+
 pub(crate) fn use_path(p: &mut Parser) {
-    if !AnyOf(&[IDENT, SELF_KW, SUPER_KW, COLONCOLON]).is_ahead(p) {
+    if !is_path_start(p) {
         return;
     }
     let mut prev = p.mark();
@@ -10,11 +14,17 @@ pub(crate) fn use_path(p: &mut Parser) {
     });
     many(p, |p| {
         let curr = p.mark();
-        node_if(p, COLONCOLON, PATH, |p| {
-            path_segment(p, false);
-            p.forward_parent(prev, curr);
-            prev = curr;
-        })
+        if p.current() == COLONCOLON && !items::is_use_tree_start(p.raw_lookahead(1)) {
+            node(p, PATH, |p| {
+                p.bump();
+                path_segment(p, false);
+                p.forward_parent(prev, curr);
+                prev = curr;
+            });
+            true
+        } else {
+            false
+        }
     });
 }