[java-inspections] IDEA-315406 "Field may be static" false positive

GitOrigin-RevId: 4ef30cb64f236cc976ad3573d14388121c4bdb94

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

@@ -29,11 +29,14 @@ class CanBeStaticVisitor extends JavaRecursiveElementWalkingVisitor {
     }
   }
 
+  @Override
+  public void visitThisExpression(@NotNull PsiThisExpression expression) {
+    canBeStatic = false;
+    stopWalking();
+  }
+
   @Override
   public void visitReferenceExpression(@NotNull PsiReferenceExpression ref) {
-    if (!canBeStatic) {
-      return;
-    }
     super.visitReferenceExpression(ref);
     PsiElement element = ref.resolve();
 
@@ -41,6 +44,7 @@ class CanBeStaticVisitor extends JavaRecursiveElementWalkingVisitor {
         !owner.hasModifierProperty(PsiModifier.STATIC) &&
         !(owner instanceof PsiClass cls && ClassUtil.isTopLevelClass(cls))) {
       canBeStatic = false;
+      stopWalking();
     }
   }
 

plugins/InspectionGadgets/test/com/siyeh/igtest/performance/field_may_be_static/FieldMayBeStatic.java

@@ -66,4 +66,9 @@ class Outer {
     }.run();
   }
 
-}
+}
+class ThisExpression {
+  private final boolean test = this instanceof Sub;
+
+  static class Sub extends ThisExpression {}
+}