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cannot return a function from a generic function #22011
Description
Describe the bug
module parselona
pub struct ParserResult[O] {
i []u8
o O
}
type TParser[O] = fn([]u8) !ParserResult[O]
type TF[O] = fn([]u8) O
fn take_part(count int) TParser[[]u8] {
return fn [count] (i []u8) !ParserResult[[]u8] {
if i.len<count { return error('error len: ${i}') }
return ParserResult[[]u8] {
i: i[count..],
o: i[..count],
}
}
}
fn fmap<O>(p TParser[[]u8], f TF[O]) TParser[O] {
return fn [p, f] <O>(i []u8) !ParserResult[O] {
r:=p(i)!
return ParserResult[O]{i:r.i, o:f<O>(r.o)}
}
}
fn test_1() {
input := '10_ttt_uuuu_qqq_'.bytes()
f := ParserResult[int] {
i: [u8(1),u8(2)]
o: 1
}
nnn:=take_part(2)
println('hhhhh ${nnn(input)!}')
fnf := fn(i[]u8) int { return 1 }
n := fmap[int](nnn, fnf)
f1 := n(input) or { println('errr') return }
println('hhhhh ${f1}')
assert ['nn'] == ['ttt_', 'uuuu_', 'qqq_']
}Reproduction Steps
v test parselona_test.v
Expected Behavior
complit test
Current Behavior
FAIL 0.000 ms /home/prof/projects/v/parselona/src/parselona_test.v
compilation failed:
parselona.v:49:9: error: cannot use `fn ([]u8) !parselona.ParserResult[O]` as type `fn ([]u8) !parselona.ParserResult[int]` in return argument
47 |
48 | fn fmap<O>(p TParser[[]u8], f TF[O]) TParser[O] {
49 | return fn [p, f] <O>(i []u8) !ParserResult[O] {
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
50 | r:=p(i)!
51 | return ParserResult[O]{i:r.i, o:f<O>(r.o)}
Possible Solution
for some reason type parametr not expansion
Additional Information/Context
No response
V version
V 0.4.7 3ca5bc3
Environment details (OS name and version, etc.)
Linux Mint 22
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Activity
Cergoo commentedon Aug 8, 2024
see #13253
medvednikov commentedon Aug 9, 2024
A simple reproducible example:
medvednikov commentedon Aug 9, 2024
It's related to @yuyi98's fix #15529
cannot return a function from a generic function (fixes #22011)
cannot return a function from a generic function (fixes #22011)
cannot return a function from a generic function (fixes #22011)
checker: cannot return a function from a generic function (fixes #22011)
checker: cannot return a function from a generic function (fixes vlan…