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, 15 insertions, 0 deletions

diff --git a/crates/ra_hir_def/src/resolver.rs b/crates/ra_hir_def/src/resolver.rs
index 2734d51a0..123fae72a 100644
--- a/crates/ra_hir_def/src/resolver.rs
+++ b/crates/ra_hir_def/src/resolver.rs
@@ -381,6 +381,11 @@ impl Resolver {
         db: &impl DefDatabase,
         path: &ModPath,
     ) -> Option<MacroDefId> {
+        // Search item scope legacy macro first
+        if let Some(def) = self.resolve_local_macro_def(path) {
+            return Some(def);
+        }
+
         let (item_map, module) = self.module_scope()?;
         item_map.resolve_path(db, module, &path, BuiltinShadowMode::Other).0.take_macros()
     }
@@ -413,6 +418,16 @@ impl Resolver {
         })
     }
 
+    fn resolve_local_macro_def(&self, path: &ModPath) -> Option<MacroDefId> {
+        let name = path.as_ident()?;
+        self.scopes.iter().rev().find_map(|scope| {
+            if let Scope::LocalItemsScope(body) = scope {
+                return body.item_scope.get_legacy_macro(name);
+            }
+            None
+        })
+    }
+
     pub fn module(&self) -> Option<ModuleId> {
         let (def_map, local_id) = self.module_scope()?;
         Some(ModuleId { krate: def_map.krate, local_id })