[perl #125988] [BUG] Redeclaration of return type in nested signature insufficiently forbidden in Rakudo

[Carl Mäsak]

# New Ticket Created by  "Carl Mäsak" 
# Please include the string:  [perl #125988]
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# <URL: https://rt.perl.org/Ticket/Display.html?id=125988 >


<masak_venue> m: sub foo( Str &b:(Bool --> Int) ) { say "alive" };
foo( sub (Bool) { 42 } )
<camelia> rakudo-moar e6f360: OUTPUT«Type check failed in binding &b;
expected 'Callable[Str]' but got 'Sub'␤  in sub foo at
/tmp/fBPFLs3lWv:1␤  in block <unit> at /tmp/fBPFLs3lWv:1␤␤»
* masak_venue submits rakudobug
<jnthn> masak_venue: Wait, why?
<masak_venue> (it ignores the inner/Int return type directive)
<jnthn> Oh...
<masak_venue> I think it should fail by forbidding doubly declaring it like that
<jnthn> Yeah, there's precedent for trying to catch such thinkos
<masak_venue> jnthn: yes, lichtkind did it by mistake and didn't even realize.
<jnthn> m: my Int foo() returns Str { }
<camelia> rakudo-moar e6f360: OUTPUT«===SORRY!===␤Type 'Int' is not
declared. Did you mean 'int'?␤at /tmp/FG3lZlDRBh:1␤------> my Int
⏏foo() returns Str { }␤Malformed my␤at /tmp/FG3lZlDRBh:1␤------> my
Int ⏏foo() returns Str { }␤␤»
<masak_venue> it would be nice to catch it and throw the perfect error message
<jnthn> m: my Int sub foo() returns Str { }
<camelia> rakudo-moar e6f360: OUTPUT«===SORRY!=== Error while
compiling /tmp/RNk5jWh_lG␤Redeclaration of return type for foo
(previous return type was Int)␤at /tmp/RNk5jWh_lG:1␤»
<jnthn> Something like that
<masak_venue> yes, that one