src/jdk/nashorn/internal/runtime/UnwarrantedOptimismException.java

*** 47,66 ****
      private Object returnValue;
      private final int    programPoint;
      private final Type   returnType;
  
      /**
!      * Constructor
       * @param returnValue actual return value from the too narrow operation
       * @param programPoint program point where unwarranted optimism was detected
       */
      public UnwarrantedOptimismException(final Object returnValue, final int programPoint) {
          this(returnValue, programPoint, getReturnType(returnValue));
      }
  
      /**
!      * Check if a program point is valid
       * @param programPoint the program point
       * @return true if valid
       */
      public static boolean isValid(final int programPoint) {
          assert programPoint >= INVALID_PROGRAM_POINT;
--- 47,69 ----
      private Object returnValue;
      private final int    programPoint;
      private final Type   returnType;
  
      /**
!      * Constructor without explicit return type. The return type is determined statically from the class of
!      * the return value, and only canonical internal number representations are recognized. Use
!      * {@link #createNarrowest} if you want to handle float and long values as numbers instead of objects.
!      *
       * @param returnValue actual return value from the too narrow operation
       * @param programPoint program point where unwarranted optimism was detected
       */
      public UnwarrantedOptimismException(final Object returnValue, final int programPoint) {
          this(returnValue, programPoint, getReturnType(returnValue));
      }
  
      /**
!      * Check if a program point is valid.
       * @param programPoint the program point
       * @return true if valid
       */
      public static boolean isValid(final int programPoint) {
          assert programPoint >= INVALID_PROGRAM_POINT;
*** 68,79 ****
      }
  
      private static Type getReturnType(final Object v) {
          if (v instanceof Double) {
              return Type.NUMBER;
-         } else if (v instanceof Long) {
-             return Type.LONG;
          }
          assert !(v instanceof Integer) : v + " is an int"; // Can't have an unwarranted optimism exception with int
          return Type.OBJECT;
      }
  
--- 71,80 ----
*** 95,104 ****
--- 96,121 ----
          this.programPoint = programPoint;
          this.returnType   = returnType;
      }
  
      /**
+      * Create an {@code UnwarrantedOptimismException} with the given return value and program point, narrowing
+      * the type to {@code number} if the value is a float or a long that can be represented as double.
+      *
+      * @param returnValue the return value
+      * @param programPoint the program point
+      * @return the exception
+      */
+     public static UnwarrantedOptimismException createNarrowest(final Object returnValue, final int programPoint) {
+         if (returnValue instanceof Float
+                 || (returnValue instanceof Long && JSType.isRepresentableAsDouble((Long) returnValue))) {
+             return new UnwarrantedOptimismException(((Number) returnValue).doubleValue(), programPoint, Type.NUMBER);
+         }
+         return new UnwarrantedOptimismException(returnValue, programPoint);
+     }
+ 
+     /**
       * Get the return value. This is a destructive readout, after the method is invoked the return value is null'd out.
       * @return return value
       */
      public Object getReturnValueDestructive() {
          final Object retval = returnValue;