do not highlight enum constants as unused when values are used (IDEA-65298 )

java/java-impl/src/com/intellij/codeInsight/daemon/impl/PostHighlightingPass.java

@@ -61,6 +61,7 @@ import com.intellij.profile.codeInspection.InspectionProjectProfileManager;
 import com.intellij.psi.*;
 import com.intellij.psi.codeStyle.JavaCodeStyleManager;
 import com.intellij.psi.impl.PsiClassImplUtil;
+import com.intellij.psi.impl.source.PsiClassImpl;
 import com.intellij.psi.impl.source.jsp.jspJava.JspxImportStatement;
 import com.intellij.psi.jsp.JspFile;
 import com.intellij.psi.jsp.JspSpiUtil;
@@ -542,12 +543,32 @@ public class PostHighlightingPass extends TextEditorHighlightingPass {
 
     //search usages if it cheap
     //if count is 0 there is no usages since we've called myRefCountHolder.isReferenced() before
-    if (cheapEnough == PsiSearchHelper.SearchCostResult.ZERO_OCCURRENCES && !canbeReferencedViaWeirdNames(member)) return true;
+    if (cheapEnough == PsiSearchHelper.SearchCostResult.ZERO_OCCURRENCES) {
+      if (member instanceof PsiEnumConstant) {
+        return checkEnumValuesUsages(member, progress);
+      }
+      if (!canbeReferencedViaWeirdNames(member)) return true;
+    }
 
     Query<PsiReference> query = member instanceof PsiMethod
                                 ? MethodReferencesSearch.search((PsiMethod)member, scope, true)
                                 : ReferencesSearch.search(member, scope, true);
-    return query.findFirst() == null;
+    final PsiReference first = query.findFirst();
+    if (first == null && member instanceof PsiEnumConstant) {
+      return checkEnumValuesUsages(member, progress);
+    }
+    return first == null;
+  }
+
+  private boolean checkEnumValuesUsages(PsiMember member, ProgressIndicator progress) {
+    final PsiClassImpl containingClass = (PsiClassImpl)member.getContainingClass();
+    if (containingClass != null) {
+      final PsiMethod valuesMethod = containingClass.getValuesMethod();
+      if (valuesMethod != null && weAreSureThereAreNoUsages(valuesMethod, progress)) {
+        return true;
+      }
+    }
+    return false;
   }
 
   private static boolean canbeReferencedViaWeirdNames(PsiMember member) {

java/java-impl/src/com/intellij/codeInspection/reference/RefJavaElementImpl.java

@@ -25,6 +25,7 @@ import com.intellij.openapi.util.Iconable;
 import com.intellij.psi.*;
 import com.intellij.psi.impl.source.jsp.jspJava.JspClass;
 import com.intellij.psi.impl.source.jsp.jspJava.JspHolderMethod;
+import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.IconUtil;
 import gnu.trove.THashSet;
 import org.jetbrains.annotations.NotNull;
@@ -231,6 +232,21 @@ public abstract class RefJavaElementImpl extends RefElementImpl implements RefJa
       }
       addOutReference(refWhat);
       ((RefJavaElementImpl)refWhat).markReferenced(this, psiFrom, psiWhat, forWriting, forReading, expression);
+    } else {
+      if (psiWhat instanceof PsiMethod) {
+        final PsiClass containingClass = ((PsiMethod)psiWhat).getContainingClass();
+        if (containingClass != null && containingClass.isEnum() && "values".equals(((PsiMethod)psiWhat).getName())) {
+          for (PsiField enumConstant : containingClass.getFields()) {
+            if (enumConstant instanceof PsiEnumConstant) {
+              final RefJavaElementImpl enumConstantReference = (RefJavaElementImpl)getRefManager().getReference(enumConstant);
+              if (enumConstantReference != null) {
+                addOutReference(enumConstantReference);
+                enumConstantReference.markReferenced(this, psiFrom, enumConstant, false, true, expression);
+              }
+            }
+          }
+        }
+      }
     }
   }
 

java/java-impl/src/com/intellij/psi/impl/source/PsiClassImpl.java

@@ -18,6 +18,7 @@ package com.intellij.psi.impl.source;
 import com.intellij.extapi.psi.StubBasedPsiElementBase;
 import com.intellij.lang.ASTNode;
 import com.intellij.navigation.ItemPresentation;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.roots.OrderEntry;
@@ -661,4 +662,8 @@ public class PsiClassImpl extends JavaStubPsiElement<PsiClassStub<?>> implements
     return true;
   }
 
+  @Nullable
+  public PsiMethod getValuesMethod() {
+    return myValuesMethod;
+  }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting7/Unused.java

@@ -0,0 +1,22 @@
+class UnusedDeclBug {
+
+    public static enum Concern {
+        // These fields are used!  Just because I don't mention them by name
+        // doesn't mean they aren't used!
+        // IDEA tells me I need: @SuppressWarnings({"UnusedDeclaration"})
+        LOW,
+        MEDIUM,
+        HIGH;
+    };
+
+    public static void main(String[] args) {
+        System.out.println("Concerns are:");
+
+        // Invoking Concern.values() should count as using all the fields in the
+        // enum.
+        for (Concern concern : Concern.values()) {
+            System.out.print("\t");
+            System.out.println(concern);
+        } // end for
+    }
+}

java/java-tests/testData/inspection/deadCode/enumValues/expected.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>  
+</problems>
+

java/java-tests/testData/inspection/deadCode/enumValues/src/Test.java

@@ -0,0 +1,22 @@
+public class UnusedDeclBug {
+
+    public static enum Concern {
+        // These fields are used!  Just because I don't mention them by name
+        // doesn't mean they aren't used!
+        // IDEA tells me I need: @SuppressWarnings({"UnusedDeclaration"})
+        LOW,
+        MEDIUM,
+        HIGH;
+    };
+
+    public static void main(String[] args) {
+        System.out.println("Concerns are:");
+
+        // Invoking Concern.values() should count as using all the fields in the
+        // enum.
+        for (Concern concern : Concern.values()) {
+            System.out.print("\t");
+            System.out.println(concern);
+        } // end for
+    }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/LightAdvHighlightingJdk7Test.java

@@ -47,6 +47,12 @@ public class LightAdvHighlightingJdk7Test extends LightDaemonAnalyzerTestCase {
     doTest(BASE_PATH + "/" + getTestName(false) + ".java", checkWarnings, checkInfos);
   }
 
+  @Override
+  protected void setUp() throws Exception {
+
+    super.setUp();
+  }
+
   @Override
   protected LocalInspectionTool[] configureLocalInspectionTools() {
     return new LocalInspectionTool[]{
@@ -275,4 +281,9 @@ public class LightAdvHighlightingJdk7Test extends LightDaemonAnalyzerTestCase {
     enableInspectionTool(new UnusedDeclarationInspection());
     doTest(true, false);
   }
+
+  public void testUnused() throws Exception {
+    enableInspectionTool(new UnusedDeclarationInspection());
+    doTest(true, false);
+  }
 }

java/java-tests/testSrc/com/intellij/codeInspection/UnusedDeclarationTest.java

@@ -172,4 +172,8 @@ public class UnusedDeclarationTest extends InspectionTestCase {
   public void testenumInstantiation() throws Exception {
     doTest();
   }
+
+  public void testenumValues() throws Exception {
+    doTest();
+  }
 }