[java-inspections] Field can be made static: respect implicit writes

Fixes IDEA-313564 "Field can be made 'static'" false positive with Lombok

GitOrigin-RevId: f9e6acb2a4e673bebe9d6379d9a5e5869708b107

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/performance/FieldMayBeStaticInspection.java

@@ -15,6 +15,7 @@
  */
 package com.siyeh.ig.performance;
 
+import com.intellij.codeInsight.daemon.impl.UnusedSymbolUtil;
 import com.intellij.codeInsight.daemon.impl.analysis.HighlightingFeature;
 import com.intellij.psi.*;
 import com.intellij.psi.util.PsiUtil;
@@ -76,6 +77,9 @@ public class FieldMayBeStaticInspection extends BaseInspection {
         // inner class cannot have static declarations in earlier Java versions
         return;
       }
+      if (UnusedSymbolUtil.isImplicitWrite(field)) {
+        return;
+      }
       if (containingClass instanceof PsiAnonymousClass && 
           !HighlightingFeature.INNER_STATICS.isAvailable(containingClass) &&
           !PsiUtil.isCompileTimeConstant(field)) {

plugins/lombok/src/test/java/de/plushnikov/intellij/plugin/inspection/LombokFieldMayBeStaticInspectionTest.java

@@ -0,0 +1,21 @@
+package de.plushnikov.intellij.plugin.inspection;
+
+import com.intellij.codeInspection.InspectionProfileEntry;
+import com.siyeh.ig.performance.FieldMayBeStaticInspection;
+
+public class LombokFieldMayBeStaticInspectionTest extends LombokInspectionTest {
+
+  @Override
+  protected String getBasePath() {
+    return super.getBasePath() + "/" + TEST_DATA_INSPECTION_DIRECTORY + "/canBeStaticInspection";
+  }
+
+  @Override
+  protected InspectionProfileEntry getInspection() {
+    return new FieldMayBeStaticInspection();
+  }
+
+  public void testDefault() {
+    doTest();
+  }
+}

plugins/lombok/testData/inspection/canBeStaticInspection/Default.java

@@ -0,0 +1,15 @@
+import lombok.Builder;
+
+@Builder
+class Main {
+  @Builder.Default
+  private final int y = 3;
+
+  void test() {
+    System.out.println(y);
+  }
+
+  public void main(String[] args) {
+    System.out.println(y);
+  }
+}