IDEA-84754 Completion preselect the specified value if it is selected in editor

java/java-tests/testData/codeInsight/completion/normal/PreselectEditorSelection.java

@@ -0,0 +1,7 @@
+public class FooBar {
+
+    int a() {
+        <caret><selection>finalize</selection>
+    }
+
+}

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

@@ -632,6 +632,12 @@ public class ListUtils {
   public void testQualifierAsPackage3() throws Throwable {
     doTest();
   }
+
+  public void testPreselectEditorSelection() {
+    configure()
+    assert lookup.currentItem != myFixture.lookupElements[0]
+    assert 'finalize' == lookup.currentItem.lookupString
+  }
   
   public void testPackageNamedVariableBeforeAssignment() throws Throwable {
     doTest();

platform/lang-impl/src/com/intellij/codeInsight/completion/CompletionLookupArranger.java

@@ -215,9 +215,11 @@ public class CompletionLookupArranger extends LookupArranger {
       }
     }
 
+    String selectedText = lookup.getEditor().getSelectionModel().getSelectedText();
     for (int i = 0; i < items.size(); i++) {
       LookupElement item = items.get(i);
-      if (isPrefixItem(lookup, item, true) && !isLiveTemplate(item)) {
+      if (isPrefixItem(lookup, item, true) && !isLiveTemplate(item) ||
+          item.getLookupString().equals(selectedText)) {
         return i;
       }
     }