IDEA-230729 Good code red: Illegal generic type for instanceof

GitOrigin-RevId: 03fa8e1c2e663e50bd0968423fe07a9a7e05a0d1

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

@@ -820,7 +820,7 @@ public class GenericsHighlightUtil {
       if (type instanceof PsiClassType && ((PsiClassType)type).resolve() == aClass) return null;
     }
 
-    if (PsiUtil.isCompileTimeConstant((PsiVariable)field)) return null;
+    if (PsiUtil.isCompileTimeConstant(field)) return null;
 
     String description = JavaErrorBundle.message(
       "illegal.to.access.static.member.from.enum.constructor.or.instance.initializer",
@@ -925,10 +925,23 @@ public class GenericsHighlightUtil {
     return result;
   }
 
-  static HighlightInfo checkInstanceOfGenericType(@NotNull PsiInstanceOfExpression expression) {
+  static HighlightInfo checkInstanceOfGenericType(@NotNull LanguageLevel languageLevel, @NotNull PsiInstanceOfExpression expression) {
     final PsiTypeElement checkTypeElement = expression.getCheckType();
     if (checkTypeElement == null) return null;
-    return isIllegalForInstanceOf(checkTypeElement.getType(), checkTypeElement);
+    PsiType checkType = checkTypeElement.getType();
+    if (HighlightUtil.Feature.PATTERNS.isSufficient(languageLevel)) {
+      return isUnsafeCastInInstanceOf(checkTypeElement, checkType, expression.getOperand().getType());
+    }
+    return isIllegalForInstanceOf(checkType, checkTypeElement);
+  }
+
+  private static HighlightInfo isUnsafeCastInInstanceOf(PsiTypeElement checkTypeElement, PsiType checkType, PsiType expressionType) {
+    if (expressionType != null && JavaGenericsUtil.isUncheckedCast(checkType, expressionType)) {
+      String description = JavaErrorBundle.message("unsafe.cast.in.instanceof",
+                                                   expressionType.getPresentableText(), checkType.getPresentableText());
+      return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(checkTypeElement).descriptionAndTooltip(description).create();
+    }
+    return null;
   }
 
   /**

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

@@ -819,7 +819,7 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
   public void visitInstanceOfExpression(PsiInstanceOfExpression expression) {
     super.visitInstanceOfExpression(expression);
     if (!myHolder.hasErrorResults()) myHolder.add(HighlightUtil.checkInstanceOfApplicable(expression));
-    if (!myHolder.hasErrorResults()) myHolder.add(GenericsHighlightUtil.checkInstanceOfGenericType(expression));
+    if (!myHolder.hasErrorResults()) myHolder.add(GenericsHighlightUtil.checkInstanceOfGenericType(myLanguageLevel, expression));
   }
 
   @Override

java/java-psi-impl/src/messages/JavaErrorBundle.properties

@@ -102,6 +102,7 @@ generics.duplicate.type.parameter=Duplicate type parameter: ''{0}''
 generics.cannot.catch.type.parameters=Cannot catch type parameters
 generics.cannot.instanceof.type.parameters=Class or array expected
 illegal.generic.type.for.instanceof=Illegal generic type for instanceof
+unsafe.cast.in.instanceof=''{0}'' cannot be safely cast to ''{1}''
 cannot.select.dot.class.from.type.variable=Cannot select from a type variable
 method.does.not.override.super=Method does not override method from its superclass
 call.to.super.is.not.allowed.in.enum.constructor=Call to super is not allowed in enum constructor

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlightingPatterns/InstanceOfNonReified.java

@@ -0,0 +1,22 @@
+import java.util.ArrayList;
+import java.util.List;
+
+interface Iface {}
+class Cls implements Iface {}
+class Foo<T> {}
+
+class InstanceOfNonReified {
+  void test(List<Cls> o) {
+    boolean b1 = o instanceof ArrayList<Cls>;
+    boolean b2 = <error descr="Inconvertible types; cannot cast 'java.util.List<Cls>' to 'java.util.ArrayList<Iface>'">o instanceof ArrayList<Iface></error>;
+    boolean b3 = o instanceof <error descr="'List<Cls>' cannot be safely cast to 'Foo<Cls>'">Foo<Cls></error>;
+  }
+
+  public static void main(String [] args) {
+
+    Object o = new ArrayList<Object>();
+    if (o instanceof <error descr="'Object' cannot be safely cast to 'ArrayList<Integer>'">ArrayList<Integer></error> ai) {
+      System.out.println("");
+    }
+  }
+}

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

@@ -38,6 +38,9 @@ public class LightPatternsHighlightingTest extends LightJavaCodeInsightFixtureTe
     myFixture.enableInspections(new UnusedDeclarationInspection());
     doTest();
   }
+  public void testInstanceOfNonReified() {
+    doTest();
+  }
 
   private void doTest() {
     myFixture.configureByFile(getTestName(false) + ".java");