scala> Seq(1) ++ (2 to 3).toArray
<console>:8: error: polymorphic expression cannot be instantiated to expected type;
 found   : [B >: Int]Array[B]
 required: scala.collection.GenTraversableOnce[?]
              Seq(1) ++ (2 to 3).toArray
                                 ^
error: type mismatch;
 found   : Array[?B]
 required: scala.collection.GenTraversableOnce[?]
Note that implicit conversions are not applicable because they are ambiguous:
 both method booleanArrayOps in object Predef of type (xs: Array[Boolean])scala.collection.mutable.ArrayOps[Boolean]
 and method byteArrayOps in object Predef of type (xs: Array[Byte])scala.collection.mutable.ArrayOps[Byte]
 are possible conversion functions from Array[?B] to scala.collection.GenTraversableOnce[?]
error: type mismatch;
 found   : Array[?B]
 required: scala.collection.GenTraversableOnce[?]
Note that implicit conversions are not applicable because they are ambiguous:
 both method booleanArrayOps in object Predef of type (xs: Array[Boolean])scala.collection.mutable.ArrayOps[Boolean]
 and method byteArrayOps in object Predef of type (xs: Array[Byte])scala.collection.mutable.ArrayOps[Byte]
 are possible conversion functions from Array[?B] to scala.collection.GenTraversableOnce[?]
error: type mismatch;
 found   : Array[?B]
 required: scala.collection.GenTraversableOnce[?]
Note that implicit conversions are not applicable because they are ambiguous:
 both method booleanArrayOps in object Predef of type (xs: Array[Boolean])scala.collection.mutable.ArrayOps[Boolean]
 and method byteArrayOps in object Predef of type (xs: Array[Byte])scala.collection.mutable.ArrayOps[Byte]
 are possible conversion functions from Array[?B] to scala.collection.GenTraversableOnce[?]

scala> 1
error: type mismatch;
 found   : Array[?B]
 required: scala.collection.GenTraversableOnce[?]
Note that implicit conversions are not applicable because they are ambiguous:
 both method booleanArrayOps in object Predef of type (xs: Array[Boolean])scala.collection.mutable.ArrayOps[Boolean]
 and method byteArrayOps in object Predef of type (xs: Array[Byte])scala.collection.mutable.ArrayOps[Byte]
 are possible conversion functions from Array[?B] to scala.collection.GenTraversableOnce[?]
error: type mismatch;
 found   : Array[?B]
 required: scala.collection.GenTraversableOnce[?]
Note that implicit conversions are not applicable because they are ambiguous:
 both method booleanArrayOps in object Predef of type (xs: Array[Boolean])scala.collection.mutable.ArrayOps[Boolean]
 and method byteArrayOps in object Predef of type (xs: Array[Byte])scala.collection.mutable.ArrayOps[Byte]
 are possible conversion functions from Array[?B] to scala.collection.GenTraversableOnce[?]
error: type mismatch;
 found   : Array[?B]
 required: scala.collection.GenTraversableOnce[?]
Note that implicit conversions are not applicable because they are ambiguous:
 both method booleanArrayOps in object Predef of type (xs: Array[Boolean])scala.collection.mutable.ArrayOps[Boolean]
 and method byteArrayOps in object Predef of type (xs: Array[Byte])scala.collection.mutable.ArrayOps[Byte]
 are possible conversion functions from Array[?B] to scala.collection.GenTraversableOnce[?]