2 files changed, 39 insertions, 6 deletions

diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index 141c9072f..2a1ed9b81 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -63,8 +63,15 @@ impl HirFileId {
         match file_id.0 {
             HirFileIdRepr::File(file_id) => db.parse(file_id),
             HirFileIdRepr::Macro(macro_call_id) => {
-                // returning an empty string looks fishy...
-                parse_macro(db, macro_call_id).unwrap_or_else(|| SourceFile::parse(""))
+                parse_macro(db, macro_call_id).unwrap_or_else(|| {
+                    // Note:
+                    // The final goal we would like to make all parse_macro success,
+                    // such that the following log will not call anyway.
+                    log::warn!("fail on macro_parse: {}", macro_call_id.debug_dump(db));
+
+                    // returning an empty string looks fishy...
+                    SourceFile::parse("")
+                })
             }
         }
     }
@@ -299,3 +306,16 @@ impl AstItemDef<ast::TypeAliasDef> for TypeAliasId {
         db.lookup_intern_type_alias(self)
     }
 }
+
+impl MacroCallId {
+    pub fn debug_dump(&self, db: &impl DefDatabase) -> String {
+        let loc = self.clone().loc(db);
+        let node = loc.ast_id.to_node(db);
+        let syntax_str = node.syntax().to_string();
+
+        // dump the file name
+        let file_id: HirFileId = self.clone().into();
+        let original = file_id.original_file(db);
+        format!("macro call [file: {:#?}] : {}", db.file_relative_path(original), syntax_str)
+    }
+}
diff --git a/crates/ra_hir/src/nameres/collector.rs b/crates/ra_hir/src/nameres/collector.rs
index 39cadc94a..6147b3219 100644
--- a/crates/ra_hir/src/nameres/collector.rs
+++ b/crates/ra_hir/src/nameres/collector.rs
@@ -42,6 +42,7 @@ pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> C
         unresolved_imports: Vec::new(),
         unexpanded_macros: Vec::new(),
         global_macro_scope: FxHashMap::default(),
+        marco_stack_count: 0,
     };
     collector.collect();
     collector.finish()
@@ -55,6 +56,10 @@ struct DefCollector<DB> {
     unresolved_imports: Vec<(CrateModuleId, raw::ImportId, raw::ImportData)>,
     unexpanded_macros: Vec<(CrateModuleId, AstId<ast::MacroCall>, Path)>,
     global_macro_scope: FxHashMap<Name, MacroDefId>,
+
+    /// Some macro use `$tt:tt which mean we have to handle the macro perfectly
+    /// To prevent stackoverflow, we add a deep counter here for prevent that.
+    marco_stack_count: u32,
 }
 
 impl<'a, DB> DefCollector<&'a DB>
@@ -324,10 +329,18 @@ where
     }
 
     fn collect_macro_expansion(&mut self, module_id: CrateModuleId, macro_call_id: MacroCallId) {
-        let file_id: HirFileId = macro_call_id.into();
-        let raw_items = self.db.raw_items(file_id);
-        ModCollector { def_collector: &mut *self, file_id, module_id, raw_items: &raw_items }
-            .collect(raw_items.items())
+        self.marco_stack_count += 1;
+
+        if self.marco_stack_count < 300 {
+            let file_id: HirFileId = macro_call_id.into();
+            let raw_items = self.db.raw_items(file_id);
+            ModCollector { def_collector: &mut *self, file_id, module_id, raw_items: &raw_items }
+                .collect(raw_items.items())
+        } else {
+            log::error!("Too deep macro expansion: {}", macro_call_id.debug_dump(self.db));
+        }
+
+        self.marco_stack_count -= 1;
     }
 
     fn finish(self) -> CrateDefMap {