Enum.valueOf and annotations methods are not-null (IDEA-151305, IDEA-151174)

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

@@ -70,9 +70,18 @@ public class DfaPsiUtil {
       return Nullness.UNKNOWN;
     }
 
-    if (owner instanceof PsiEnumConstant) {
+    if (owner instanceof PsiEnumConstant || PsiUtil.isAnnotationMethod(owner)) {
       return Nullness.NOT_NULL;
     }
+    if (owner instanceof PsiMethod) {
+      PsiMethod method = (PsiMethod)owner;
+      if ("valueOf".equals(method.getName()) && method.hasModifierProperty(PsiModifier.STATIC)) {
+        PsiClass containingClass = method.getContainingClass();
+        if (containingClass != null && containingClass.isEnum()) {
+          return Nullness.NOT_NULL;
+        }
+      }
+    }
 
     if (resultType != null) {
       NullableNotNullManager nnn = NullableNotNullManager.getInstance(owner.getProject());

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

@@ -0,0 +1,11 @@
+class Test {
+  @interface FooBar {
+    String x();
+  }
+
+  static void baz(FooBar annotation) {
+    if (<warning descr="Condition 'annotation.x() == null' is always 'false'">annotation.x() == null</warning>) {
+      System.out.println("null");
+    }
+  }
+}

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

@@ -12,6 +12,10 @@ class FooWithComments {
     }
   }
 
+  boolean checkValueOf(String name) {
+    return <warning descr="Condition 'AnEnum.valueOf(name) != null' is always 'true'">AnEnum.valueOf(name) != null</warning>;
+  }
+
   private native void anotherMethod(String name);
 
   @Nullable

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

@@ -91,6 +91,8 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   public void testGreaterIsNotEquals() throws Throwable { doTest(); }
   public void testNotGreaterIsNotEquals() throws Throwable { doTest(); }
 
+  public void testAnnotationMethodNotNull() { doTest(); }
+
   public void testChainedFinalFieldsDfa() throws Throwable { doTest(); }
   public void testFinalFieldsDifferentInstances() throws Throwable { doTest(); }
   public void testThisFieldGetters() throws Throwable { doTest(); }