fixed PY-15437 Exception when converting method to function

python/src/com/jetbrains/python/inspections/quickfix/PyMakeFunctionFromMethodQuickFix.java

@@ -67,17 +67,17 @@ public class PyMakeFunctionFromMethodQuickFix implements LocalQuickFix {
 
     PsiElement copy = problemFunction.copy();
     problemFunction.delete();
-    final PsiFile file = containingClass.getContainingFile();
+    final PsiElement parent = containingClass.getParent();
     PyClass aClass = PsiTreeUtil.getTopmostParentOfType(containingClass, PyClass.class);
     if (aClass == null)
       aClass = containingClass;
-    copy = file.addBefore(copy, aClass);
+    copy = parent.addBefore(copy, aClass);
 
     for (UsageInfo usage : usages) {
       final PsiElement usageElement = usage.getElement();
       if (usageElement instanceof PyReferenceExpression) {
         final PsiFile usageFile = usageElement.getContainingFile();
-        updateUsage(copy, (PyReferenceExpression)usageElement, usageFile, !usageFile.equals(file));
+        updateUsage(copy, (PyReferenceExpression)usageElement, usageFile, !usageFile.equals(parent));
       }
     }
   }

python/testData/quickFixes/PyMakeFunctionFromMethodQuickFixTest/localClass.py

@@ -0,0 +1,4 @@
+def make_server(config):
+    class Handler(object):
+        def method_<caret>name2(self, x):
+            x.send_error(404, 'File not found')

python/testData/quickFixes/PyMakeFunctionFromMethodQuickFixTest/localClass_after.py

@@ -0,0 +1,6 @@
+def make_server(config):
+    def method_name2(x):
+        x.send_error(404, 'File not found')
+
+    class Handler(object):
+        pass

python/testSrc/com/jetbrains/python/quickFixes/PyMakeFunctionFromMethodQuickFixTest.java

@@ -75,4 +75,8 @@ public class PyMakeFunctionFromMethodQuickFixTest extends PyQuickFixTestCase {
   public void testUsageSelf() {
     doQuickFixTest(PyMethodMayBeStaticInspection.class, PyBundle.message("QFIX.NAME.make.function"));
   }
+
+  public void testLocalClass() {
+    doQuickFixTest(PyMethodMayBeStaticInspection.class, PyBundle.message("QFIX.NAME.make.function"));
+  }
 }