Mutability: support initialized final fields

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/Mutability.java

@@ -6,6 +6,7 @@ package com.intellij.codeInspection.dataFlow;
 import com.intellij.codeInsight.AnnotationUtil;
 import com.intellij.psi.*;
 import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.psi.util.PsiUtil;
 import com.intellij.util.ObjectUtils;
 import org.jetbrains.annotations.NotNull;
 
@@ -52,6 +53,13 @@ public enum Mutability {
                                    AnnotationUtil.CHECK_INFERRED)) {
       return UNMODIFIABLE_VIEW;
     }
+    if (owner instanceof PsiField && owner.hasModifierProperty(PsiModifier.FINAL)) {
+      PsiExpression initializer = PsiUtil.skipParenthesizedExprDown(((PsiField)owner).getInitializer());
+      if (initializer instanceof PsiMethodCallExpression) {
+        PsiMethod method = ((PsiMethodCallExpression)initializer).resolveMethod();
+        return method == null ? UNKNOWN : getMutability(method);
+      }
+    }
     return UNKNOWN;
   }
 }

java/java-tests/testData/inspection/dataFlow/fixture/MutabilityJdk.java

@@ -2,6 +2,11 @@ import java.util.*;
 import java.io.*;
 
 public class MutabilityJdk {
+  static final List<String> LIST = Collections.unmodifiableList(Arrays.asList("foo", "bar"));
+
+  void testField() {
+    LIST.<warning descr="Immutable object is modified">add</warning>("baz");
+  }
 
   void testEmpty() {
     List<String> list = Collections.emptyList();