IDEA-58766 Recognize dot as completion prefix part for chained call suggestions

java/java-tests/testSrc/com/intellij/codeInsight/completion/JavaAutoPopupTest.groovy

@@ -1221,4 +1221,16 @@ class Foo {{
     myFixture.checkResult 'class Foo { int foo() { re(<caret>) }}'
   }
 
+  public void testAmbiguousClassQualifier() {
+    myFixture.addClass("package foo; public class Util { public static void foo() {} }")
+    myFixture.addClass("package bar; public class Util { public static void bar() {} }")
+    myFixture.configureByText 'a.java', 'class Foo {{ <caret> }}'
+    type 'Util.'
+    assert myFixture.lookupElementStrings == ['Util.bar', 'Util.foo']
+    type 'fo\n'
+    myFixture.checkResult '''import foo.Util;
+
+class Foo {{ Util.foo();<caret> }}'''
+  }
+
 }