use as name for completion of import elements (PY-3672)

python/src/com/jetbrains/python/psi/resolve/VariantsProcessor.java

@@ -128,9 +128,10 @@ public class VariantsProcessor implements PsiScopeProcessor {
     else if (element instanceof NameDefiner) {
       boolean handled_as_imported = false;
       if (element instanceof PyImportElement) {
-        PyReferenceExpression ref = ((PyImportElement)element).getImportReference();
+        final PyImportElement importElement = (PyImportElement)element;
+        PyReferenceExpression ref = importElement.getImportReference();
         if (ref != null && ref.getQualifier() == null) {
-          String name = ref.getName();
+          String name = importElement.getAsName() != null ? importElement.getAsName() : ref.getName();
           if (name != null && nameIsAcceptable(name)) {
             PsiElement resolved = ref.getReference().resolve();
             if (resolved instanceof PsiNamedElement) {

python/testData/completion/alias.after.py

@@ -0,0 +1,2 @@
+import datetime as timedate
+timedate

python/testData/completion/alias.py

@@ -0,0 +1,2 @@
+import datetime as timedate
+timeda<caret>

python/testSrc/com/jetbrains/python/PythonCompletionTest.java

@@ -380,4 +380,8 @@ public class PythonCompletionTest extends PyLightFixtureTestCase {
     myFixture.completeBasic();
     myFixture.checkResultByFile("completion/exportedConstants/a.after.py");
   }
+
+  public void testAlias() {  // PY-3672
+    doTest();
+  }
 }