IDEA-296461 [java]: allow replacing explicit type with var on anonymous class instantiation

GitOrigin-RevId: eeafb5c598bc5b984e0599ffdd362337cf6b8c5a

java/java-psi-impl/src/com/intellij/psi/impl/PsiDiamondTypeUtil.java

@@ -1,4 +1,4 @@
-// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.psi.impl;
 
 import com.intellij.lang.injection.InjectedLanguageManager;
@@ -148,13 +148,23 @@ public final class PsiDiamondTypeUtil {
 
   public static PsiExpression expandTopLevelDiamondsInside(PsiExpression expr) {
     if (expr instanceof PsiNewExpression) {
-      final PsiJavaCodeReferenceElement classReference = ((PsiNewExpression)expr).getClassReference();
+      PsiJavaCodeReferenceElement classReference = ((PsiNewExpression)expr).getClassReference();
+      if (classReference == null) {
+        classReference = ((PsiNewExpression)expr).getClassOrAnonymousClassReference();
+      }
       if (classReference != null) {
         final PsiReferenceParameterList parameterList = classReference.getParameterList();
         if (parameterList != null) {
           final PsiTypeElement[] typeParameterElements = parameterList.getTypeParameterElements();
           if (typeParameterElements.length == 1 && typeParameterElements[0].getType() instanceof PsiDiamondType) {
-            return  (PsiExpression)replaceDiamondWithExplicitTypes(parameterList).getParent();
+            PsiElement parent = replaceDiamondWithExplicitTypes(parameterList).getParent();
+            if (parent instanceof PsiExpression) {
+              return (PsiExpression)parent;
+            }
+            PsiElement grandParent = parent.getParent();
+            if (grandParent instanceof PsiExpression) {
+              return (PsiExpression)grandParent;
+            }
           }
         }
       }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/explicit2var/afterAnonymousGeneric.java

@@ -0,0 +1,12 @@
+// "Replace explicit type with 'var'" "true"
+import java.util.*;
+
+class X {
+  
+  void x() {
+      var list = new ArrayList<String>() {{
+      add("one");
+      add("two");
+    }};
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/explicit2var/beforeAnonymousGeneric.java

@@ -0,0 +1,12 @@
+// "Replace explicit type with 'var'" "true"
+import java.util.*;
+
+class X {
+  
+  void x() {
+    <caret>ArrayList<String> list = new ArrayList<>() {{
+      add("one");
+      add("two");
+    }};
+  }
+}