fix generator bug;

paddle/fluid/eager/auto_code_generator/final_state_generator/eager_gen.py

@@ -760,12 +760,10 @@ def GenerateNodeCreationCodes(
 
     # SetTensorWrappers
     set_tensor_wrappers_list = []
-    fwd_api_input_num = 0
     for name, (atype, is_fwd_input, pos) in backward_fwd_input_map.items():
         is_optional = (name in optional_inputs)
 
         if is_fwd_input:
-            fwd_api_input_num += 1
             if is_optional:
                 set_tensor_wrappers = f"        if({name}.is_initialized()) grad_node->SetTensorWrapper{name}({name}, true);"
             else:
@@ -777,9 +775,7 @@ def GenerateNodeCreationCodes(
                 fwd_output_pos = forward_outputs_position_map[name][1]
                 tw_name = f"std::get<{fwd_output_pos}>(api_result)"
             else:
-                assert IsPlainTensorType(atype), atype
-                out_pos = pos - fwd_api_input_num
-                tw_name = f"std::get<{out_pos}>(api_result)"
+                tw_name = f"api_result"
 
             if is_optional:
                 set_tensor_wrappers = f"        if({tw_name}.is_initialized()) grad_node->SetTensorWrapper{name}({tw_name}, false);"