redundant cast: support switch labels syntax (IDEA-226175)

GitOrigin-RevId: afdf87f8692f610ee87b9892c61f9ab97986bab8

java/java-analysis-impl/src/com/intellij/psi/util/RedundantCastUtil.java

@@ -646,6 +646,13 @@ public class RedundantCastUtil {
         }
       }
 
+      if (parent instanceof PsiExpressionStatement &&
+          operand instanceof PsiFunctionalExpression &&
+          parent.getParent() instanceof PsiSwitchLabeledRuleStatement &&
+          !castTo.equals(PsiTypesUtil.getExpectedTypeByParent(parent))) {
+        return;
+      }
+
       if (arrayAccessAtTheLeftSideOfAssignment(parent, typeCast)) {
         if (TypeConversionUtil.isAssignable(opType, castTo, false) && opType.getArrayDimensions() == castTo.getArrayDimensions()) {
           addToResults(typeCast);

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/switchExpressions/RedundantCastInSwitchBranch.java

@@ -0,0 +1,9 @@
+import java.util.function.Predicate;
+
+class RedundantCast {
+  private static void foo(final int matchType) {
+    Object o = switch (matchType) {
+      default -> (Predicate<Object>) target -> target == null;
+    };
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/JavaSwitchExpressionsHighlightingTest.kt

@@ -2,6 +2,7 @@
 package com.intellij.java.codeInsight.daemon
 
 import com.intellij.JavaTestUtil
+import com.intellij.codeInspection.redundantCast.RedundantCastInspection
 import com.intellij.testFramework.fixtures.LightJavaCodeInsightFixtureTestCase
 
 class JavaSwitchExpressionsHighlightingTest : LightJavaCodeInsightFixtureTestCase() {
@@ -17,6 +18,10 @@ class JavaSwitchExpressionsHighlightingTest : LightJavaCodeInsightFixtureTestCas
   fun testEnhancedSwitchUnreachable() = doTest()
   fun testSwitchExpressionHasResult() = doTest()
   fun testYieldStatements() = doTest()
+  fun testRedundantCastInSwitchBranch() {
+    myFixture.enableInspections(RedundantCastInspection())
+    doTest()
+  }
 
   private fun doTest() {
     myFixture.configureByFile("${getTestName(false)}.java")