Inconsistent interface among .substr/.substr-eq/.substr-rw

[zoffixznet]

I'd imagine these routines are similar enough that they'd be able to take the same args, but non-.substr candidates don't seem to be able to take Callables and don't coerce non-Int args to Ints.

<Zoffix__> m: say "Long string".substr: 3, {6}
<camelia> rakudo-moar 404f30217: OUTPUT: «g stri␤»
<Zoffix__> m: say "Long string".substr-eq: 3, {6}
<camelia> rakudo-moar 404f30217: OUTPUT: «Cannot resolve caller substr-eq(Str: Int, Block); none of these signatures match:␤    (Str:D $: Cool:D $needle, *%_)␤    (Str:D $: Str:D $needle, *%_)␤    (Str:D $: Cool:D $needle, Int:D $pos, *%_)␤    (Str:D $: Str:D $needle, Int:D $pos, *%_)…»
<Zoffix__> m: say "Long string".substr-rw: 3, {6}
<camelia> rakudo-moar 404f30217: OUTPUT: «Cannot resolve caller Numeric(Block: ); none of these signatures match:␤    (Mu:U \v: *%_)␤  in block <unit> at <tmp> line 1␤␤»
<Zoffix__> m: say "Long string".substr-rw: {6}, 3
<camelia> rakudo-moar 404f30217: OUTPUT: «tri␤»
<Zoffix__> m: say "Long string".substr-eq: {6}, 3
<camelia> rakudo-moar 404f30217: OUTPUT: «Cannot resolve caller substr-eq(Str: Block, Int); none of these signatures match:␤    (Str:D $: Cool:D $needle, *%_)␤    (Str:D $: Str:D $needle, *%_)␤    (Str:D $: Cool:D $needle, Int:D $pos, *%_)␤    (Str:D $: Str:D $needle, Int:D $pos, *%_)…»

<Zoffix__> m: say "Long string".substr-eq: 3.3, 3.3
<camelia> rakudo-moar 404f30217: OUTPUT: «Cannot resolve caller substr-eq(Str: Rat, Rat); none of these signatures match:␤    (Str:D $: Cool:D $needle, *%_)␤    (Str:D $: Str:D $needle, *%_)␤    (Str:D $: Cool:D $needle, Int:D $pos, *%_)␤    (Str:D $: Str:D $needle, Int:D $pos, *%_)…»