[Dy2St]Refine AnnAssign in static_analysis (#39572)

Author: 0x45f

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

@@ -349,7 +349,11 @@ def _get_node_var_type(self, cur_wrapper):
             ret_type = {NodeVarType.type_from_annotation(node.annotation)}
             # if annotation and value(Constant) are diffent type, we use value type
             if node.value:
-                ret_type = self.node_to_wrapper_map[node.value].node_var_type
+                node_value_type = self.node_to_wrapper_map[
+                    node.value].node_var_type
+                if not (node_value_type &
+                        {NodeVarType.UNKNOWN, NodeVarType.STATEMENT}):
+                    ret_type = node_value_type
             if isinstance(node.target, gast.Name):
                 self.node_to_wrapper_map[node.target].node_var_type = ret_type
                 self.var_env.set_var_type(node.target.id, ret_type)

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

@@ -147,6 +147,7 @@ def add(x, y):
 def func_to_test7(a: int, b: float, c: paddle.Tensor, d: float='diff'):
     a = True
     e, f = paddle.shape(c)
+    g: paddle.Tensor = len(c)
 
 
 result_var_type7 = {
@@ -155,7 +156,8 @@ def func_to_test7(a: int, b: float, c: paddle.Tensor, d: float='diff'):
     'c': {NodeVarType.TENSOR},
     'd': {NodeVarType.STRING},
     'e': {NodeVarType.PADDLE_RETURN_TYPES},
-    'f': {NodeVarType.PADDLE_RETURN_TYPES}
+    'f': {NodeVarType.PADDLE_RETURN_TYPES},
+    'g': {NodeVarType.TENSOR}
 }
 
 test_funcs = [