Merge #3591

3591: Support local macro_rules r=matklad a=edwin0cheng

This PR implement local `macro_rules` in function body, by adding following things:

1. While lowering, add a `MacroDefId` in body's `ItemScope` as a textual legacy macro. 
2. Make `Expander::enter_expand` search with given `ItemScope`.
3. Make `Resolver::resolve_path_as_macro` search with `LocalItemScope`.

Fix #2181

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

1 files changed, 9 insertions, 3 deletions

diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
index 57ba45b45..2bc405a59 100644
--- a/crates/ra_hir_def/src/body.rs
+++ b/crates/ra_hir_def/src/body.rs
@@ -47,13 +47,19 @@ impl Expander {
     pub(crate) fn enter_expand<T: ast::AstNode, DB: DefDatabase>(
         &mut self,
         db: &DB,
+        local_scope: Option<&ItemScope>,
         macro_call: ast::MacroCall,
     ) -> Option<(Mark, T)> {
         let macro_call = InFile::new(self.current_file_id, &macro_call);
 
-        if let Some(call_id) =
-            macro_call.as_call_id(db, |path| self.resolve_path_as_macro(db, &path))
-        {
+        if let Some(call_id) = macro_call.as_call_id(db, |path| {
+            if let Some(local_scope) = local_scope {
+                if let Some(def) = path.as_ident().and_then(|n| local_scope.get_legacy_macro(n)) {
+                    return Some(def);
+                }
+            }
+            self.resolve_path_as_macro(db, &path)
+        }) {
             let file_id = call_id.as_file();
             if let Some(node) = db.parse_or_expand(file_id) {
                 if let Some(expr) = T::cast(node) {