Conversions from slice to array pointer

[vsivsi]

Go 1.17 introduces a small but useful new language feature:

Converting a slice to an array pointer yields a pointer to the underlying array of the slice. If the length of the slice is less than the length of the array, a run-time panic occurs.

s := make([]byte, 2, 4)
s0 := (*[0]byte)(s)      // s0 != nil
s1 := (*[1]byte)(s[1:])  // &s1[0] == &s[1]
s2 := (*[2]byte)(s)      // &s2[0] == &s[0]
s4 := (*[4]byte)(s)      // panics: len([4]byte) > len(s)

var t []string
t0 := (*[0]string)(t)    // t0 == nil
t1 := (*[1]string)(t)    // panics: len([1]string) > len(t)

u := make([]byte, 0)
u0 = (*[0]byte)(u)       // u0 != nil

Obviously gomacro doesn't yet support this because it's new. E.g.:

gomacro> s := make([]byte, 2, 4)
gomacro> s
[0 0]	// []uint8
gomacro> s0 := (*[2]byte)(s)
repl.go:1:18: cannot convert []uint8 to *[2]uint8: s

[cosmos72]

Yes, this new language feature should be implemented.
No idea when I will have time for that, though