HighlightControlFlowUtil: disable assignment to pattern variables

GitOrigin-RevId: 09c4aa42068ce0258543a17546404fcdec952404

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

@@ -624,19 +624,23 @@ public class HighlightControlFlowUtil {
     }
     PsiReferenceExpression reference = ObjectUtils.tryCast(PsiUtil.skipParenthesizedExprDown(operand), PsiReferenceExpression.class);
     PsiVariable variable = reference == null ? null : ObjectUtils.tryCast(reference.resolve(), PsiVariable.class);
-    if (variable == null || !variable.hasModifierProperty(PsiModifier.FINAL)) return null;
-    final boolean canWrite = canWriteToFinal(variable, expression, reference, containingFile) && checkWriteToFinalInsideLambda(variable, reference) == null;
-    if (canWrite) return null;
+    if (!(variable instanceof PsiPatternVariable)) {
+      if (variable == null || !variable.hasModifierProperty(PsiModifier.FINAL)) return null;
+      final boolean canWrite = canWriteToFinal(variable, expression, reference, containingFile) && checkWriteToFinalInsideLambda(variable, reference) == null;
+      if (canWrite) return null;
+    }
     final String name = variable.getName();
     String description = JavaErrorMessages.message("assignment.to.final.variable", name);
     final HighlightInfo highlightInfo =
       HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(reference).descriptionAndTooltip(description).create();
-    final PsiElement innerClass = getInnerClassVariableReferencedFrom(variable, expression);
-    if (innerClass == null || variable instanceof PsiField) {
-      HighlightFixUtil.registerMakeNotFinalAction(variable, highlightInfo);
-    }
-    else {
-      QuickFixAction.registerQuickFixAction(highlightInfo, QUICK_FIX_FACTORY.createVariableAccessFromInnerClassFix(variable, innerClass));
+    if (!(variable instanceof PsiPatternVariable)) {
+      final PsiElement innerClass = getInnerClassVariableReferencedFrom(variable, expression);
+      if (innerClass == null || variable instanceof PsiField) {
+        HighlightFixUtil.registerMakeNotFinalAction(variable, highlightInfo);
+      }
+      else {
+        QuickFixAction.registerQuickFixAction(highlightInfo, QUICK_FIX_FACTORY.createVariableAccessFromInnerClassFix(variable, innerClass));
+      }
     }
     return highlightInfo;
   }

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

@@ -0,0 +1,7 @@
+class X {
+  void expressions(Object obj) {
+    if (obj instanceof String s) {
+      <error descr="Cannot assign a value to final variable 's'">s</error> = "foo";
+    }
+  }
+}

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

@@ -27,6 +27,9 @@ public class LightPatternsHighlightingTest extends LightJavaCodeInsightFixtureTe
   public void testInstanceOfControlFlow() {
     doTest();
   }
+  public void testReassignPatternVariable() {
+    doTest();
+  }
 
   private void doTest() {
     myFixture.configureByFile(getTestName(false) + ".java");