don't apply loose isReferenceTo() logic of qualified references with unknown qualifier type to __init__ calls (otherwise we get very weird results when searching usages of class) (PY-1450)

python/src/com/jetbrains/python/psi/impl/PyQualifiedReferenceImpl.java

@@ -8,6 +8,7 @@ import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
 import com.intellij.util.ArrayUtil;
 import com.intellij.util.ProcessingContext;
+import com.jetbrains.python.PyNames;
 import com.jetbrains.python.psi.*;
 import com.jetbrains.python.psi.patterns.SyntaxMatchers;
 import com.jetbrains.python.psi.resolve.*;
@@ -242,7 +243,7 @@ public class PyQualifiedReferenceImpl extends PyReferenceImpl {
     }
     final String referencedName = myElement.getReferencedName();
     if (element instanceof PyFunction && Comparing.equal(referencedName, ((PyFunction)element).getName()) &&
-        ((PyFunction)element).getContainingClass() != null) {
+        ((PyFunction)element).getContainingClass() != null && !PyNames.INIT.equals(referencedName)) {
       final PyExpression qualifier = myElement.getQualifier();
       if (qualifier != null && qualifier.getType(TypeEvalContext.fast()) == null) {
         return true;

python/testData/findUsages/UnresolvedClassInit.py

@@ -0,0 +1,3 @@
+class <caret>B(C):
+    def __init__(self):
+        C.__init__(self)

python/testSrc/com/jetbrains/python/PyFindUsagesTest.java

@@ -54,6 +54,11 @@ public class PyFindUsagesTest extends PyLightFixtureTestCase {
     assertUsages(usages, "<caret>parm+1");
   }
 
+  public void testUnresolvedClassInit() {   // PY-1450
+    final Collection<UsageInfo> usages = myFixture.testFindUsages("findUsages/UnresolvedClassInit.py");
+    assertUsages(usages);
+  }
+
   private void assertUsages(Collection<UsageInfo> usages, String... usageTexts) {
     assertEquals(usageTexts.length, usages.size());
     List<UsageInfo> sortedUsages = new ArrayList<UsageInfo>(usages);