IG: Support pattern matching for instanceof

GitOrigin-RevId: e35db4b8fffc27b8f9f5b5e380f24ff2a950f76e

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/psiutils/EquivalenceChecker.java

@@ -840,7 +840,16 @@ public class EquivalenceChecker {
     }
     final PsiTypeElement typeElement1 = instanceOfExpression1.getCheckType();
     final PsiTypeElement typeElement2 = instanceOfExpression2.getCheckType();
-    return typeElementsAreEquivalent(typeElement1, typeElement2);
+    if (!typeElementsAreEquivalent(typeElement1, typeElement2).isExactMatch()) {
+      return EXACT_MISMATCH;
+    }
+    PsiPatternVariable patternVariable1 = JavaPsiPatternUtil.getPatternVariable(instanceOfExpression1.getPattern());
+    PsiPatternVariable patternVariable2 = JavaPsiPatternUtil.getPatternVariable(instanceOfExpression2.getPattern());
+    if (patternVariable1 == null || patternVariable2 == null) {
+      return Match.exact(patternVariable1 == patternVariable2);
+    }
+    markDeclarationsAsEquivalent(patternVariable1, patternVariable2);
+    return EXACT_MATCH;
   }
 
   protected Match typeElementsAreEquivalent(PsiTypeElement typeElement1, PsiTypeElement typeElement2) {

plugins/InspectionGadgets/test/com/siyeh/igtest/inheritance/redundant_method_override/InstanceOf.java

@@ -0,0 +1,39 @@
+class Foo {
+  void test1(Object o) {
+    if (((o instanceof ((String s)) && ((s.length() > 42))))) {
+      System.out.println(s);
+    }
+  }
+
+  void test2(Object o) {
+    if (o instanceof String s && s.length() > 42) {
+      System.out.println(s);
+    }
+  }
+
+  void test3(Object o) {
+    if (o instanceof String s && s.length() > 42) {
+      System.out.println(s);
+    }
+  }
+}
+
+class Bar extends Foo {
+  void <warning descr="Method 'test1()' is identical to its super method">test1</warning>(Object o) {
+    if (o instanceof String str && str.length() > 42) {
+      System.out.println(str);
+    }
+  }
+
+  void test2(Object o) {
+    if (o instanceof CharSequence str && str.length() > 42) {
+      System.out.println(str);
+    }
+  }
+
+  void test3(Object o) {
+    if (o instanceof String str && str.length() > 0) {
+      System.out.println(str);
+    }
+  }
+}

plugins/InspectionGadgets/testsrc/com/siyeh/ig/inheritance/RedundantMethodOverrideInspection17Test.java

@@ -21,4 +21,8 @@ public class RedundantMethodOverrideInspection17Test extends LightJavaInspection
   public void testSwitch() {
     doTest();
   }
+
+  public void testInstanceOf() {
+    doTest();
+  }
 }