Update return detection

trans/transpiler/phases/emit_cpp/block.py

@@ -124,11 +124,11 @@ class BlockVisitor(NodeVisitor):
             def visit_ClassDef(self, node: ast.ClassDef):
                 yield from ()
 
-        has_return = ReturnVisitor().match(node.body)
+            def check(self, f):
+                for b in node.body:
+                    yield from self.match(node)
 
-        for child in node.body:
-            from transpiler.phases.emit_cpp.function import FunctionVisitor
-            child_visitor = FunctionVisitor(inner_scope, CoroutineMode.ASYNC)
+        has_return = next(ReturnVisitor().check(node), False)
 
         yield from self.visit_func_decls(node.body, inner_scope)