isEffectivelyFinal: disallow effectively final variables to be initialized twice (IDEA-165060)

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

@@ -723,16 +723,15 @@ public class HighlightControlFlowUtil {
         return true;
       }
 
-      final List<PsiReferenceExpression> readBeforeWriteLocals = ControlFlowUtil.getReadBeforeWriteLocals(controlFlow);
-      for (PsiReferenceExpression expression : readBeforeWriteLocals) {
-        if (expression.resolve() == variable) {
-          return PsiUtil.isAccessedForReading(expression);
-        }
-      }
-
       final Collection<ControlFlowUtil.VariableInfo> initializedTwice = ControlFlowUtil.getInitializedTwice(controlFlow);
       effectivelyFinal = !initializedTwice.contains(new ControlFlowUtil.VariableInfo(variable, null));
       if (effectivelyFinal) {
+        final List<PsiReferenceExpression> readBeforeWriteLocals = ControlFlowUtil.getReadBeforeWriteLocals(controlFlow);
+        for (PsiReferenceExpression expression : readBeforeWriteLocals) {
+          if (expression.resolve() == variable) {
+            return PsiUtil.isAccessedForReading(expression);
+          }
+        }
         effectivelyFinal = notAccessedForWriting(variable, new LocalSearchScope(scope));
       }
     }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/highlighting/EffectiveFinal.java

@@ -175,4 +175,16 @@ class AssignmentToFinalInsideLambda {
       }
     };
   }
+}
+
+class NonInitializedButWrittenTwice {
+  private void test(boolean b) {
+    int s;
+    if(b) {
+      s = 1;
+      J is = () -> <error descr="Variable used in lambda expression should be final or effectively final">s</error>;
+      System.out.println(is.m());
+    }
+    <error descr="Variable 's' might not have been initialized">s</error>++;
+  }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeMayBeNotInitializedAndThusNotEffectivelyFinal.java

@@ -0,0 +1,20 @@
+// "Replace with collect" "false"
+
+import java.util.ArrayList;
+import java.util.List;
+
+class Main {
+  public List<Integer> test(boolean b, List<String> list) {
+    int s;
+    if(b) {
+      s = 1;
+    }
+    List<Integer> result = new ArrayList<>();
+    for(String str : li<caret>st) {
+      if(str != null) {
+        result.add(s++);
+      }
+    }
+    return result;
+  }
+}