IDEA-139253 TYPE_USE @Nullable-Annotations don't work correctly with arrays

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

@@ -212,7 +212,7 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
 
   private void flushArrayElementsOnUnknownIndexAssignment(PsiExpression lExpr) {
     if (lExpr instanceof PsiArrayAccessExpression &&
-        myFactory.createValue(lExpr) == null // check for unknown index, otherwise AssignInstruction will flush only that element
+        !(myFactory.createValue(lExpr) instanceof DfaVariableValue) // check for unknown index, otherwise AssignInstruction will flush only that element
       ) {
       DfaValue arrayVar = myFactory.createValue(((PsiArrayAccessExpression)lExpr).getArrayExpression());
       if (arrayVar instanceof DfaVariableValue) {

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

@@ -70,13 +70,6 @@ public class DfaPsiUtil {
       return Nullness.UNKNOWN;
     }
 
-    if (NullableNotNullManager.isNullable(owner)) {
-      return Nullness.NULLABLE;
-    }
-    if (NullableNotNullManager.isNotNull(owner)) {
-      return Nullness.NOT_NULL;
-    }
-
     if (resultType != null) {
       NullableNotNullManager nnn = NullableNotNullManager.getInstance(owner.getProject());
       for (PsiAnnotation annotation : resultType.getAnnotations()) {
@@ -95,6 +88,13 @@ public class DfaPsiUtil {
       }
     }
 
+    if (NullableNotNullManager.isNullable(owner)) {
+      return Nullness.NULLABLE;
+    }
+    if (NullableNotNullManager.isNotNull(owner)) {
+      return Nullness.NOT_NULL;
+    }
+
     return Nullness.UNKNOWN;
   }
 

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/value/DfaExpressionFactory.java

@@ -70,6 +70,7 @@ public class DfaExpressionFactory {
       return getExpressionDfaValue(((PsiParenthesizedExpression)expression).getExpression());
     }
 
+    PsiType type = expression.getType();
     if (expression instanceof PsiArrayAccessExpression) {
       PsiExpression arrayExpression = ((PsiArrayAccessExpression)expression).getArrayExpression();
       DfaValue qualifier = getExpressionDfaValue(arrayExpression);
@@ -79,7 +80,9 @@ public class DfaExpressionFactory {
           return myFactory.getVarFactory().createVariableValue(indexVar, expression.getType(), false, (DfaVariableValue)qualifier);
         }
       }
-      return null;
+      if (type != null) {
+        return myFactory.createTypeValue(type, DfaPsiUtil.getElementNullability(type, null));
+      }
     }
 
     if (expression instanceof PsiMethodCallExpression) {
@@ -99,7 +102,6 @@ public class DfaExpressionFactory {
     }
 
     final Object value = JavaConstantExpressionEvaluator.computeConstantExpression(expression, false);
-    PsiType type = expression.getType();
     if (value != null && type != null) {
       if (value instanceof String) {
         return myFactory.createTypeValue(type, Nullness.NOT_NULL); // Non-null string literal.

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

@@ -0,0 +1,27 @@
+import foo.*;
+
+import java.util.List;
+
+class TestCompilerWarnings {
+  public void m(@NotNull Object x) {
+    assert x != null;
+  }
+
+  public void test1Array(@Nullable String @NotNull [] x) {
+    if (<warning descr="Condition 'x == null' is always 'false'">x == null</warning>) {
+      System.out.println("x is null");
+    }
+    m(x);
+    m(<warning descr="Argument 'x[0]' might be null">x[0]</warning>);
+  }
+
+  public void test2Array(@NotNull String @Nullable [] x) {
+    if (x == null) {
+      System.out.println("x is null");
+    } else {
+      m(x[0]);
+    }
+    m(<warning descr="Argument 'x' might be null">x</warning>);
+  }
+
+}

java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspection8Test.java

@@ -83,4 +83,12 @@ public class DataFlowInspection8Test extends LightCodeInsightFixtureTestCase {
     setupCustomAnnotations();
     doTest();
   }
+
+  public void testNullableArrayComponent() {
+    setupCustomAnnotations();
+    final DataFlowInspection inspection = new DataFlowInspection();
+    inspection.IGNORE_ASSERT_STATEMENTS = true;
+    myFixture.enableInspections(inspection);
+    myFixture.testHighlighting(true, false, true, getTestName(false) + ".java");
+  }
 }