Shortcut `block_def_map` if there's no inner items

This previously didn't work, but apparently only because of the wonky
test setup

2 files changed, 8 insertions, 5 deletions

diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index bc61730a7..540c6c9ad 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -700,10 +700,13 @@ impl ExprCollector<'_> {
         let ast_id = self.expander.ast_id(&block);
         let block_loc = BlockLoc { ast_id, module: self.expander.module };
         let block_id = self.db.intern_block(block_loc);
-        let def_map = self.db.block_def_map(block_id);
-        let root = def_map.module_id(def_map.root());
+        let opt_def_map = self.db.block_def_map(block_id);
+        let has_def_map = opt_def_map.is_some();
+        let def_map = opt_def_map.unwrap_or_else(|| self.expander.def_map.clone());
+        let module =
+            if has_def_map { def_map.module_id(def_map.root()) } else { self.expander.module };
         let prev_def_map = mem::replace(&mut self.expander.def_map, def_map);
-        let prev_module = mem::replace(&mut self.expander.module, root);
+        let prev_module = mem::replace(&mut self.expander.module, module);
 
         self.collect_stmts_items(block.statements());
         let statements =
diff --git a/crates/hir_def/src/body/tests.rs b/crates/hir_def/src/body/tests.rs
index da60072ce..404603360 100644
--- a/crates/hir_def/src/body/tests.rs
+++ b/crates/hir_def/src/body/tests.rs
@@ -43,7 +43,7 @@ fn block_def_map_at(ra_fixture: &str) -> Arc<DefMap> {
     let mut block =
         block_at_pos(&db, &def_map, position).expect("couldn't find enclosing function or block");
     loop {
-        let def_map = db.block_def_map(block);
+        let def_map = db.block_def_map(block).unwrap_or_else(|| def_map.clone());
         let new_block = block_at_pos(&db, &def_map, position);
         match new_block {
             Some(new_block) => {
@@ -58,6 +58,7 @@ fn block_def_map_at(ra_fixture: &str) -> Arc<DefMap> {
 }
 
 fn block_at_pos(db: &dyn DefDatabase, def_map: &DefMap, position: FilePosition) -> Option<BlockId> {
+    // Find the smallest (innermost) function containing the cursor.
     let mut size = None;
     let mut fn_def = None;
     for (_, module) in def_map.modules() {
@@ -73,7 +74,6 @@ fn block_at_pos(db: &dyn DefDatabase, def_map: &DefMap, position: FilePosition)
                 let ast = ast_map.get(item_tree[it.lookup(db).id.value].ast_id).to_node(&root);
                 let range = ast.syntax().text_range();
 
-                // Find the smallest (innermost) function containing the cursor.
                 if !range.contains(position.offset) {
                     continue;
                 }