Re: [scala-language] Inconsistent behaviour of bitwise operators

[Som Snytt]

The spec says the result should be the type of the receiver, and the op is overloaded for Int and Long, but constant folding doesn't honor that when there is a Long involved.

1.toInt is not folded, so that's why r6 stays an Int.

I notice the scaladoc for >> says left instead of right.  The boy sitting next to me on the bus to a field trip sang endlessly, "This is my right hand way up high, this is my left hand touch the sky."

"A bit stupid" is a good pun for this case.

On Fri, Mar 28, 2014 at 5:18 PM, Michał Pociecha <michal....@gmail.com> wrote:

Hello,
I'm curious why bitwise operators for certain numeric types work in such a strange way.

scala> :paste
// Entering paste mode (ctrl-D to finish)

val int: Int = 1
val long = 2L

val r = int << long
val r2 = int << 2L
val r3 = 1 << long
val r4 = 1 << 2L
val r5 = 1.toInt << long // right, a bit stupid but just to check it out
val r6 = 1.toInt << 2L

// Exiting paste mode, now interpreting.

int: Int = 1
long: Long = 2
r: Int = 4
r2: Int = 4
r3: Int = 4
r4: Long = 4
r5: Int = 4
r6: Int = 4

r4: The compiler changes this 1: Int to Long but why? Is it a bug?

Thanks,
Michal

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