Refactor: replace make_simplified_union with UnionType.make_union in plugins/default.py (#8624)

This commit replaces all calls to make_simplified_union with UnionType.make_union in this file, as part of the codebase modernization effort in issue #8624.

Author: lsrafael13

mypy/plugins/default.py

@@ -222,7 +222,7 @@ def typed_dict_get_signature_callback(ctx: MethodSigContext) -> CallableType:
             tv = signature.variables[0]
             assert isinstance(tv, TypeVarType)
             return signature.copy_modified(
-                arg_types=[signature.arg_types[0], make_simplified_union([value_type, tv])],
+                arg_types=[signature.arg_types[0], UnionType.make_union([value_type, tv])],
                 ret_type=ret_type,
             )
     return signature
@@ -263,7 +263,7 @@ def typed_dict_get_callback(ctx: MethodContext) -> Type:
         if len(ctx.arg_types) == 1:
             output_types.append(NoneType())
 
-        return make_simplified_union(output_types)
+        return UnionType.make_union(output_types)
     return ctx.default_return_type
 
 
@@ -292,7 +292,7 @@ def typed_dict_pop_signature_callback(ctx: MethodSigContext) -> CallableType:
             # variable that accepts everything.
             tv = signature.variables[0]
             assert isinstance(tv, TypeVarType)
-            typ = make_simplified_union([value_type, tv])
+            typ = UnionType.make_union([value_type, tv])
             return signature.copy_modified(arg_types=[str_type, typ], ret_type=typ)
     return signature.copy_modified(arg_types=[str_type, signature.arg_types[1]])
 
@@ -327,9 +327,9 @@ def typed_dict_pop_callback(ctx: MethodContext) -> Type:
                 return AnyType(TypeOfAny.from_error)
 
         if len(ctx.args[1]) == 0:
-            return make_simplified_union(value_types)
+            return UnionType.make_union(value_types)
         elif len(ctx.arg_types) == 2 and len(ctx.arg_types[1]) == 1 and len(ctx.args[1]) == 1:
-            return make_simplified_union([*value_types, ctx.arg_types[1][0]])
+            return UnionType.make_union([*value_types, ctx.arg_types[1][0]])
     return ctx.default_return_type
 
 
@@ -401,7 +401,7 @@ def typed_dict_setdefault_callback(ctx: MethodContext) -> Type:
 
             value_types.append(value_type)
 
-        return make_simplified_union(value_types)
+        return UnionType.make_union(value_types)
     return ctx.default_return_type
 
 
@@ -479,7 +479,7 @@ def typed_dict_update_signature_callback(ctx: MethodSigContext) -> CallableType:
                     item = item.copy_modified(item_names=list(td.items))
                 items.append(item)
             if items:
-                arg_type = make_simplified_union(items)
+                arg_type = UnionType.make_union(items)
         return signature.copy_modified(arg_types=[arg_type])
     return signature