Make sure staticmethod params are (mostly) inferred correctly, fixes #735

jedi/inference/value/instance.py

@@ -19,6 +19,7 @@ from jedi.inference.value.function import \
     BaseFunctionExecutionContext, FunctionExecutionContext
 from jedi.inference.value.klass import ClassFilter
 from jedi.inference.value.dynamic_arrays import get_dynamic_array_instance
+from jedi.parser_utils import function_is_static_method
 
 
 class InstanceExecutedParamName(ParamName):
@@ -40,7 +41,8 @@ class AnonymousMethodExecutionFilter(AnonymousFunctionExecutionFilter):
         self._instance = instance
 
     def _convert_param(self, param, name):
-        if param.position_index == 0:
+        if param.position_index == 0 \
+                and not function_is_static_method(self._function_value.tree_node):
             return InstanceExecutedParamName(self._instance, self._function_value, name)
         return super(AnonymousMethodExecutionFilter, self)._convert_param(param, name)
 

jedi/parser_utils.py

@@ -295,3 +295,11 @@ def cut_value_at_position(leaf, position):
 
 def get_string_quote(leaf):
     return re.match(r'\w*("""|\'{3}|"|\')', leaf.value).group(1)
+
+
+def function_is_static_method(function_node):
+    for decorator in function_node.get_decorators():
+        dotted_name = decorator.children[1]
+        if dotted_name.get_code() == 'staticmethod':
+            return True
+    return False