[ Dy2Static ] Remove assign split (#44769)

* just a test

* remove split assign test

* remove other useless code related to split assign

python/paddle/fluid/dygraph/dygraph_to_static/base_transformer.py

@@ -186,88 +186,6 @@ class ForLoopTuplePreTransformer(BaseTransformer):
         return [assign_node]
 
 
-class SplitAssignTransformer(BaseTransformer):
-    """
-    This class transforms sequence assignments and multi-target assignments to normal assignments.
-    """
-
-    def __init__(self, ast_node):
-        assert isinstance(ast_node, gast.AST)
-        self.ast_root = ast_node
-
-    def transform(self):
-        self.visit(self.ast_root)
-
-    def visit_Assign(self, node):
-        target_nodes = node.targets
-        if len(target_nodes) == 1:
-            node = self._parse_sequence_assign(node)
-        else:
-            node = self._parse_multi_target_assign(node)
-        return node
-
-    def _parse_sequence_assign(self, node):
-        """
-        a, b = c, d
-        ->
-        a = c
-        b = d
-        """
-        assert isinstance(node, gast.Assign)
-
-        target_nodes = node.targets
-        value_node = node.value
-        if not isinstance(target_nodes[0], (gast.List, gast.Tuple)):
-            return node
-        if not isinstance(value_node, (gast.List, gast.Tuple)):
-            return node
-
-        targets = node.targets[0].elts
-        values = node.value.elts
-        if len(targets) != len(values):
-            return node
-
-        new_nodes = []
-        for target, value in zip(targets, values):
-            assign_node = gast.Assign(targets=[target], value=value)
-            new_nodes.append(assign_node)
-
-        return new_nodes
-
-    def _parse_multi_target_assign(self, node):
-        """
-         Example 1:
-         a = b = c
-         ->
-         b = c
-         a = b
-
-         Example 2:
-         a, b = c, d = x
-         ->
-         c,d = x
-         a = c
-         b = d
-         """
-        assert isinstance(node, gast.Assign)
-
-        target_nodes = node.targets
-        value_node = node.value
-        new_nodes = []
-        for target in reversed(target_nodes):
-            assign_node = gast.Assign(targets=[target], value=value_node)
-            # NOTE: Because assign_node can be sequence assign statement like `a,b = c,d`,
-            # it's necessary to visit this new assign_node
-            parsed_node = self.visit_Assign(assign_node)
-            if not isinstance(parsed_node, list):
-                parsed_node = [parsed_node]
-
-            new_nodes.extend(parsed_node)
-            value_node = target
-
-        return new_nodes
-
-
 class ForNodeVisitor(object):
     """
     This class parses python for statement, get transformed 3 statement components of for node

python/paddle/fluid/dygraph/dygraph_to_static/list_transformer.py

@@ -22,7 +22,6 @@ from paddle.fluid.dygraph.dygraph_to_static.utils import ast_to_source_code
 from paddle.fluid.dygraph.dygraph_to_static.utils import slice_is_num
 from paddle.fluid.dygraph.dygraph_to_static.utils import is_control_flow_to_transform
 from paddle.fluid.dygraph.dygraph_to_static.base_transformer import BaseTransformer
-from paddle.fluid.dygraph.dygraph_to_static.base_transformer import SplitAssignTransformer
 
 
 class ListTransformer(BaseTransformer):
@@ -47,7 +46,6 @@ class ListTransformer(BaseTransformer):
         self.scope_var_type_dict = var_env.get_scope_var_type()
 
     def transform(self):
-        SplitAssignTransformer(self.root).transform()
         self.visit(self.root)
         self.replace_list_with_tensor_array(self.root)
 

python/paddle/fluid/tests/unittests/dygraph_to_static/test_utils.py

@@ -57,15 +57,6 @@ class StaticCode():
         y = n
 
 
-class TestSplitAssignTransformer(unittest.TestCase):
-
-    def test_code(self):
-        answer = get_source_code(StaticCode.dyfunc_assign)
-        program_translator = ProgramTranslator()
-        code = program_translator.get_code(dyfunc_assign)
-        self.assertEqual(answer, code)
-
-
 class TestIsPaddle(unittest.TestCase):
 
     def fake_module(self):