IDEA-148491 (False positive "Field may be final")

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

@@ -525,6 +525,13 @@ public final class DefiniteAssignmentUtil {
       final PsiInstanceOfExpression instanceOfExpression = (PsiInstanceOfExpression)expression;
       checkExpression(instanceOfExpression.getOperand(), definiteAssignment, value);
     }
+    else if (expression instanceof PsiLambdaExpression) {
+      final PsiLambdaExpression lambdaExpression = (PsiLambdaExpression)expression;
+      final boolean du = definiteAssignment.isDefinitelyUnassigned();
+      definiteAssignment.set(definiteAssignment.isDefinitelyAssigned(), false);
+      checkLambdaExpression(lambdaExpression, definiteAssignment);
+      definiteAssignment.set(definiteAssignment.isDefinitelyAssigned(), du);
+    }
     else if (expression instanceof PsiMethodCallExpression) {
       final PsiMethodCallExpression methodCallExpression = (PsiMethodCallExpression)expression;
       checkMethodCallExpression(methodCallExpression, definiteAssignment, value);
@@ -653,6 +660,18 @@ public final class DefiniteAssignmentUtil {
     definiteAssignment.and(resultDa, resultDu);
   }
 
+  private static void checkLambdaExpression(PsiLambdaExpression lambdaExpression, DefiniteAssignment definiteAssignment) {
+    final PsiElement body = lambdaExpression.getBody();
+    if (body instanceof PsiExpression) {
+      final PsiExpression bodyExpression = (PsiExpression)body;
+      checkExpression(bodyExpression, definiteAssignment, BooleanExpressionValue.UNDEFINED);
+    }
+    else if (body instanceof PsiCodeBlock) {
+      final PsiCodeBlock codeBlock = (PsiCodeBlock)body;
+      checkCodeBlock(codeBlock, definiteAssignment);
+    }
+  }
+
   private static void checkMethodCallExpression(PsiMethodCallExpression methodCallExpression,
                                                 DefiniteAssignment definiteAssignment,
                                                 BooleanExpressionValue value) {

plugins/InspectionGadgets/test/com/siyeh/igtest/style/field_final/FieldMayBeFinal.java

@@ -923,6 +923,46 @@ class T64 {
     s="";
   }
 }
+class T65 {
+  private Runnable r; // may not be final
+  T65() {
+    r = () -> System.out.println(r);
+  }
+}
+class T66 {
+  private  String <warning descr="Field 's' may be 'final'">s</warning>; // may be final
+  T66() {
+    s = "10";
+    Runnable r = () -> System.out.println(s);
+  }
+}
+class T67 {
+  private  String s; // may not be final
+  T67() {
+    Runnable r = () -> System.out.println(s);
+    s = "10";
+  }
+}
+class T68 {
+  private Runnable <warning descr="Field 'r' may be 'final'">r</warning>; // may be final, compare to T65
+  T68() {
+    r = () -> System.out.println((this).r);
+  }
+}
+class T69 {
+  private String s; // may not be final
+  T69() {
+    Runnable r = () -> s = "asdf";
+  }
+}
+class T70 {
+  private String s; // may not be final
+  T70() {
+    Runnable r = () -> s = "asdf";
+    s = "";
+  }
+}
+
 class Foo {
 
   public interface Accessor<T> {