IDEA-143786 Switch over enum completion - do not prefer just typed variants

java/java-impl/src/com/intellij/codeInsight/completion/JavaCompletionStatistician.java

@@ -44,7 +44,8 @@ public class JavaCompletionStatistician extends CompletionStatistician{
       return StatisticsInfo.EMPTY;
     }
 
-    if (SUPER_CALL.accepts(location.getCompletionParameters().getPosition())) {
+    PsiElement position = location.getCompletionParameters().getPosition();
+    if (SUPER_CALL.accepts(position) || ReferenceExpressionCompletionContributor.IN_SWITCH_LABEL.accepts(position)) {
       return StatisticsInfo.EMPTY;
     }
 

java/java-impl/src/com/intellij/codeInsight/completion/JavaCompletionUtil.java

@@ -59,6 +59,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.*;
 
+import static com.intellij.codeInsight.completion.ReferenceExpressionCompletionContributor.*;
 import static com.intellij.patterns.PlatformPatterns.psiElement;
 
 public class JavaCompletionUtil {
@@ -498,15 +499,14 @@ public class JavaCompletionUtil {
                                                 @NotNull LookupElement item,
                                                 @NotNull Object object,
                                                 @NotNull PsiElement place) {
-    if (object instanceof PsiMember &&
-        Java15APIUsageInspectionBase.isForbiddenApiUsage((PsiMember)object, PsiUtil.getLanguageLevel(place))) {
-      return LookupElementDecorator.withRenderer(item, new LookupElementRenderer<LookupElementDecorator<LookupElement>>() {
+    if (shouldMarkRed(object, place)) {
+      return PrioritizedLookupElement.withExplicitProximity(LookupElementDecorator.withRenderer(item, new LookupElementRenderer<LookupElementDecorator<LookupElement>>() {
         @Override
         public void renderElement(LookupElementDecorator<LookupElement> element, LookupElementPresentation presentation) {
           element.getDelegate().renderElement(presentation);
           presentation.setItemTextForeground(JBColor.RED);
         }
-      });
+      }), -1);
     }
     if (containsMember(qualifierType, object)) {
       LookupElementRenderer<LookupElementDecorator<LookupElement>> boldRenderer =
@@ -522,6 +522,16 @@ public class JavaCompletionUtil {
     return item;
   }
 
+  private static boolean shouldMarkRed(@NotNull Object object, @NotNull PsiElement place) {
+    if (!(object instanceof PsiMember)) return false;
+    if (Java15APIUsageInspectionBase.isForbiddenApiUsage((PsiMember)object, PsiUtil.getLanguageLevel(place))) return true;
+
+    if (object instanceof PsiEnumConstant) {
+      return findConstantsUsedInSwitch(place).contains(CompletionUtil.getOriginalOrSelf((PsiEnumConstant)object));
+    }
+    return false;
+  }
+
   public static boolean containsMember(@Nullable PsiType qualifierType, @NotNull Object object) {
     if (qualifierType instanceof PsiArrayType && object instanceof PsiMember) { //length and clone()
       PsiFile file = ((PsiMember)object).getContainingFile();

java/java-impl/src/com/intellij/codeInsight/completion/ReferenceExpressionCompletionContributor.java

@@ -25,6 +25,7 @@ import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Iconable;
 import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.patterns.ElementPattern;
 import com.intellij.patterns.PsiMethodPattern;
 import com.intellij.patterns.StandardPatterns;
 import com.intellij.psi.*;
@@ -42,12 +43,12 @@ import com.intellij.psi.util.TypeConversionUtil;
 import com.intellij.util.Consumer;
 import com.intellij.util.IncorrectOperationException;
 import com.intellij.util.PlatformIcons;
+import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
@@ -74,9 +75,8 @@ public class ReferenceExpressionCompletionContributor {
       return this;
     }
   };
-
-  private ReferenceExpressionCompletionContributor() {
-  }
+  public static final ElementPattern<PsiElement> IN_SWITCH_LABEL =
+    psiElement().withSuperParent(2, psiElement(PsiSwitchLabelStatement.class).withSuperParent(2, PsiSwitchStatement.class));
 
   @NotNull 
   private static ElementFilter getReferenceFilter(PsiElement element, boolean allowRecursion) {
@@ -219,10 +219,11 @@ public class ReferenceExpressionCompletionContributor {
     return elements;
   }
 
-  public static Set<PsiField> findConstantsUsedInSwitch(PsiElement element) {
-    final Set<PsiField> used = new HashSet<PsiField>();
-    if (psiElement().withSuperParent(2, psiElement(PsiSwitchLabelStatement.class).withSuperParent(2, PsiSwitchStatement.class)).accepts(element)) {
-      PsiSwitchStatement sw = PsiTreeUtil.getParentOfType(element, PsiSwitchStatement.class);
+  @NotNull 
+  public static Set<PsiField> findConstantsUsedInSwitch(@Nullable PsiElement position) {
+    if (IN_SWITCH_LABEL.accepts(position)) {
+      Set<PsiField> used = ContainerUtil.newLinkedHashSet();
+      PsiSwitchStatement sw = PsiTreeUtil.getParentOfType(position, PsiSwitchStatement.class);
       assert sw != null;
       final PsiCodeBlock body = sw.getBody();
       assert body != null;
@@ -237,8 +238,9 @@ public class ReferenceExpressionCompletionContributor {
           }
         }
       }
+      return used;
     }
-    return used;
+    return Collections.emptySet();
   }
 
   @Nullable

java/java-tests/testData/codeInsight/completion/normalSorting/DispreferJustUsedEnumConstantsInSwitch.java

@@ -0,0 +1,11 @@
+class Foo {
+  public void get(MyEnum e) {
+    switch (e) {
+      case <caret>
+    }
+  }
+}
+
+enum MyEnum {
+  FOO, BAR, GOO
+}

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

@@ -14,9 +14,7 @@
  * limitations under the License.
  */
 
-package com.intellij.codeInsight.completion;
-
-
+package com.intellij.codeInsight.completion
 import com.intellij.JavaTestUtil
 import com.intellij.codeInsight.CodeInsightSettings
 import com.intellij.codeInsight.lookup.LookupElement
@@ -24,11 +22,12 @@ import com.intellij.codeInsight.lookup.LookupElementPresentation
 import com.intellij.codeInsight.lookup.impl.LookupImpl
 import com.intellij.codeInsight.template.impl.LiveTemplateCompletionContributor
 import com.intellij.ide.ui.UISettings
+import com.intellij.openapi.fileEditor.FileDocumentManager
 import com.intellij.psi.PsiClass
 import com.intellij.psi.PsiField
 import com.intellij.psi.PsiMethod
-import com.intellij.openapi.fileEditor.FileDocumentManager
 import com.intellij.psi.statistics.StatisticsManager
+import com.intellij.ui.JBColor
 
 public class NormalCompletionOrderingTest extends CompletionSortingTestCase {
   private static final String BASE_PATH = "/codeInsight/completion/normalSorting";
@@ -681,4 +680,15 @@ interface TxANotAnno {}
     checkPreferredItems 0, 'event', 'equals'
   }
 
+  public void testDispreferJustUsedEnumConstantsInSwitch() {
+    checkPreferredItems 0, 'BAR', 'FOO', 'GOO'
+    myFixture.type('\nbreak;\ncase ')
+
+    def items = myFixture.completeBasic()
+    assertPreferredItems 0, 'FOO', 'GOO', 'BAR'
+
+    assert LookupElementPresentation.renderElement(items[0]).itemTextForeground == JBColor.foreground()
+    assert LookupElementPresentation.renderElement(items.find { it.lookupString == 'BAR' }).itemTextForeground == JBColor.RED
+  }
+
 }