highlight unused fields implicitly assigned by extension (IDEA-166091)

java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/PostHighlightingVisitor.java

@@ -339,10 +339,16 @@ class PostHighlightingVisitor {
         return info;
       }
     }
-    else if (UnusedSymbolUtil.isImplicitUsage(myProject, field, progress)) {
+    else if (UnusedSymbolUtil.isImplicitRead(myProject, field, progress)) {
       return null;
     }
     else if (UnusedSymbolUtil.isFieldUnused(myProject, myFile, field, progress, helper)) {
+      if (UnusedSymbolUtil.isImplicitWrite(myProject, field, progress)) {
+        String message = JavaErrorMessages.message("private.field.is.not.used.for.reading", identifier.getText());
+        HighlightInfo highlightInfo = UnusedSymbolUtil.createUnusedSymbolInfo(identifier, message, myDeadCodeInfoType);
+        QuickFixAction.registerQuickFixAction(highlightInfo, QuickFixFactory.getInstance().createSafeDeleteFix(field), myDeadCodeKey);
+        return highlightInfo;
+      }
       return formatUnusedSymbolHighlightInfo(project, "field.is.not.used", field, "fields", myDeadCodeKey, myDeadCodeInfoType, identifier);
     }
     return null;

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advFixture/MarkFieldsWhichAreExplicitlyWrittenAsUnused.java

@@ -0,0 +1,4 @@
+public class <warning descr="Class 'MarkFieldsWhichAreExplicitlyWrittenAsUnused' is never used">MarkFieldsWhichAreExplicitlyWrittenAsUnused</warning> {
+
+  public String <warning descr="Private field 'implicitWrite' is assigned but never accessed">implicitWrite</warning>;
+}

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

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2000-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.codeInsight.daemon;
+
+import com.intellij.JavaTestUtil;
+import com.intellij.codeInspection.deadCode.UnusedDeclarationInspection;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiField;
+import com.intellij.psi.PsiNamedElement;
+import com.intellij.testFramework.LightProjectDescriptor;
+import com.intellij.testFramework.PlatformTestUtil;
+import com.intellij.testFramework.fixtures.LightCodeInsightFixtureTestCase;
+import org.jetbrains.annotations.NotNull;
+
+public class LightUnusedHighlightingFixtureTest extends LightCodeInsightFixtureTestCase {
+
+  @Override
+  protected void setUp() throws Exception {
+    super.setUp();
+    myFixture.enableInspections(new UnusedDeclarationInspection(true));
+  }
+
+  public void testMarkFieldsWhichAreExplicitlyWrittenAsUnused() throws Exception {
+    PlatformTestUtil.registerExtension(ImplicitUsageProvider.EP_NAME, new ImplicitUsageProvider() {
+      @Override
+      public boolean isImplicitUsage(PsiElement element) {
+        return isImplicitWrite(element);
+      }
+
+      @Override
+      public boolean isImplicitRead(PsiElement element) {
+        return false;
+      }
+
+      @Override
+      public boolean isImplicitWrite(PsiElement element) {
+        return element instanceof PsiField && "implicitWrite".equals(((PsiNamedElement)element).getName());
+      }
+    }, getTestRootDisposable());
+
+    myFixture.configureByFile(getTestName(false) + ".java");
+    myFixture.checkHighlighting();
+  }
+
+
+
+  @Override
+  protected String getBasePath() {
+    return JavaTestUtil.getRelativeJavaTestDataPath() + "/codeInsight/daemonCodeAnalyzer/advFixture";
+  }
+
+  @NotNull
+  @Override
+  protected LightProjectDescriptor getProjectDescriptor() {
+    return JAVA_8;
+  }
+}