int64(math.Inf(+1)) != math.MaxInt64

[Jonathan Pearson]

I expected int64(math.Inf(+1)) == math.MaxInt64, but it does not.

In fact, these three values are equal:

int64(math.Inf(+1))

int64(math.Inf(-1))

math.MinInt64

This surprised me, and the language spec didn't clarify this specific behavior, so I wondered whether it was intentional. If so, why?

~Jonathan

[Rob Pike]

Looks like a bug to me, so I filed https://github.com/golang/go/issues/56023

Thanks for reporting it.

-rob

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[Jan Mercl]

On Tue, Oct 4, 2022 at 4:18 AM Jonathan Pearson <cell...@gmail.com> wrote:

> I expected int64(math.Inf(+1)) == math.MaxInt64, but it does not.

Quoting from https://go.dev/ref/spec#Conversions, section
"Conversions between numeric types"

""""
In all non-constant conversions involving floating-point or complex
values, if the result type cannot represent the value the conversion
succeeds but the result value is implementation-dependent.
""""

AFAICT, this is working as intended. FTR, also in my experience,
different targets produced different results for the same values the last
time I ran into this issue some years ago.