From 539ba37e9e87f664cbaab0965a71c086adc7f158 Mon Sep 17 00:00:00 2001
From: Andrey Vlasovskikh <andrey.vlasovskikh@jetbrains.com>
Date: Thu, 26 Sep 2013 19:39:00 +0400
Subject: [PATCH] If we cannot infer the type of '__new__', return a weak class
 type (PY-10893)

---
 .../jetbrains/python/psi/impl/PyCallExpressionHelper.java | 6 ++++++
 .../CustomNewReturnInAnotherModule/a.py                   | 4 ++++
 .../CustomNewReturnInAnotherModule/b.py                   | 8 ++++++++
 .../inspections/PyUnresolvedReferencesInspectionTest.java | 5 +++++
 4 files changed, 23 insertions(+)
 create mode 100644 python/testData/inspections/PyUnresolvedReferencesInspection/CustomNewReturnInAnotherModule/a.py
 create mode 100644 python/testData/inspections/PyUnresolvedReferencesInspection/CustomNewReturnInAnotherModule/b.py

diff --git a/python/src/com/jetbrains/python/psi/impl/PyCallExpressionHelper.java b/python/src/com/jetbrains/python/psi/impl/PyCallExpressionHelper.java
index ff563cd79988..1f3d65c93fa5 100644
--- a/python/src/com/jetbrains/python/psi/impl/PyCallExpressionHelper.java
+++ b/python/src/com/jetbrains/python/psi/impl/PyCallExpressionHelper.java
@@ -408,6 +408,12 @@ public class PyCallExpressionHelper {
             if (t != null && !(t instanceof PyNoneType)) {
               return t;
             }
+            if (cls != null && t == null) {
+              final PyFunction newMethod = cls.findMethodByName(PyNames.NEW, true);
+              if (newMethod != null && !PyBuiltinCache.getInstance(call).hasInBuiltins(newMethod)) {
+                return PyUnionType.createWeakType(new PyClassTypeImpl(cls, false));
+              }
+            }
           }
           if (cls != null) {
             return new PyClassTypeImpl(cls, false);
diff --git a/python/testData/inspections/PyUnresolvedReferencesInspection/CustomNewReturnInAnotherModule/a.py b/python/testData/inspections/PyUnresolvedReferencesInspection/CustomNewReturnInAnotherModule/a.py
new file mode 100644
index 000000000000..5e6d4a745397
--- /dev/null
+++ b/python/testData/inspections/PyUnresolvedReferencesInspection/CustomNewReturnInAnotherModule/a.py
@@ -0,0 +1,4 @@
+from b import C
+
+c = C()
+c.foo()
diff --git a/python/testData/inspections/PyUnresolvedReferencesInspection/CustomNewReturnInAnotherModule/b.py b/python/testData/inspections/PyUnresolvedReferencesInspection/CustomNewReturnInAnotherModule/b.py
new file mode 100644
index 000000000000..16af06a7831e
--- /dev/null
+++ b/python/testData/inspections/PyUnresolvedReferencesInspection/CustomNewReturnInAnotherModule/b.py
@@ -0,0 +1,8 @@
+class C(object):
+    def __new__(cls):
+        return D()
+
+
+class D(object):
+    def foo(self):
+        pass
diff --git a/python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java b/python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java
index 363d4c0c7242..771c4426fe84 100644
--- a/python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java
+++ b/python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java
@@ -298,6 +298,11 @@ public class PyUnresolvedReferencesInspectionTest extends PyTestCase {
     doMultiFileTest("a.py");
   }
 
+  // PY-10893
+  public void testCustomNewReturnInAnotherModule() {
+    doMultiFileTest("a.py");
+  }
+
   private void doTest() {
     myFixture.configureByFile(TEST_DIRECTORY + getTestName(true) + ".py");
     myFixture.enableInspections(PyUnresolvedReferencesInspection.class);