DfaFactType: fixed default range for float/double; tests

Fixes test DataFlowRangeAnalysisTest.testLongRangeBasics

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

@@ -114,9 +114,8 @@ public abstract class DfaFactType<T> extends Key<T> {
         }
       }
       PsiModifierListOwner psiVariable = var.getPsiVariable();
-      LongRangeSet fromAnnotation = LongRangeSet.fromAnnotation(psiVariable);
       LongRangeSet fromType = LongRangeSet.fromType(var.getVariableType());
-      return fromType == null ? fromAnnotation : fromAnnotation.intersect(fromType);
+      return fromType == null ? null : LongRangeSet.fromAnnotation(psiVariable).intersect(fromType);
     }
 
     @Nullable

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

@@ -6,6 +6,18 @@ public class LongRangeAnnotation {
     return new Random().nextInt(100);
   }
 
+  @Nonnegative int x;
+  @Nonnegative double y;
+
+  void testField() {
+    if(<warning descr="Condition 'x < 0' is always 'false'">x < 0</warning>) {
+      System.out.println("Impossible");
+    }
+    if(y < 0) {
+      System.out.println("Doubles are not supported yet");
+    }
+  }
+
   void testAnnotated() {
     int value = method();
     if(value == 0) {