IDEA-77484 + tests

java/java-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java

@@ -16,6 +16,7 @@
 package com.intellij.codeInspection.dataFlow;
 
 import com.intellij.codeInsight.ExceptionUtil;
+import com.intellij.codeInsight.NullableNotNullManager;
 import com.intellij.codeInspection.dataFlow.instructions.*;
 import com.intellij.codeInspection.dataFlow.value.DfaUnknownValue;
 import com.intellij.codeInspection.dataFlow.value.DfaValue;
@@ -1431,6 +1432,7 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
     startElement(expression);
 
     DfaValue dfaValue = myFactory.create(expression);
+    PsiElement resolved = expression.resolve();
     if (dfaValue instanceof DfaVariableValue) {
       DfaVariableValue dfaVariable = (DfaVariableValue)dfaValue;
       PsiVariable psiVariable = dfaVariable.getPsiVariable();
@@ -1442,7 +1444,7 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
     final PsiExpression qualifierExpression = expression.getQualifierExpression();
     if (qualifierExpression != null) {
       qualifierExpression.accept(this);
-      if (expression.resolve() instanceof PsiField) {
+      if (resolved instanceof PsiField) {
         addInstruction(new FieldReferenceInstruction(expression, null));
       }
       else {
@@ -1450,6 +1452,12 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
       }
     }
 
+    if (dfaValue == null && resolved instanceof PsiField) {
+      // Accessing a field from another instance
+      dfaValue = myFactory.getTypeFactory().create(((PsiField)resolved).getType(),
+                                                   NullableNotNullManager.isNullable((PsiModifierListOwner)resolved));
+    }
+
     addInstruction(new PushInstruction(dfaValue, expression));
 
     finishElement(expression);

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

@@ -0,0 +1,14 @@
+import org.jetbrains.annotations.Nullable;
+
+public class DDD {
+  int test(boolean t) {
+    if (t && <warning descr="Dereference of 'fff()' may produce 'java.lang.NullPointerException'">fff()</warning>.length == 1) {
+      return 0;
+    }
+    return 1;
+  }
+
+  public @Nullable DDD[] fff() {
+    return new DDD[8];
+  }
+}

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

@@ -0,0 +1,9 @@
+import org.jetbrains.annotations.Nullable;
+
+public class DDD {
+  @Nullable
+  String field;
+  int test() {
+    return <warning descr="Method invocation 'new DDD().field.hashCode()' may produce 'java.lang.NullPointerException'">new DDD().field.hashCode()</warning>;
+  }
+}

java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionFixtureTest.java

@@ -33,5 +33,6 @@ public class DataFlowInspectionFixtureTest extends JavaCodeInsightFixtureTestCas
   public void testNullableAnonymousVolatileNotNull() throws Throwable { doTest(); }
 
   public void testFieldInAnonymous() throws Throwable { doTest(); }
-
+  public void testNullableField() throws Throwable { doTest(); }
+  public void testCanBeNullDoesntImplyIsNull() throws Throwable { doTest(); }
 }