Nim Devel generates invalid C code

[HJarausch]

proc FP[T](A: var openArray[T], myCmp : proc(x,y:T):T): int =
  1

proc FS[T](A: var openArray[T], myCmp : proc(x,y:T):T = system.cmp[T]): int =
  result= FP(A, myCmp)

const
  N= 6
  K= 3
var A :array[N,float]= [7.0,4,6,3,9,1]

func myCmp(x,y:float):float =
  (if x==y : 0 elif x<y : -1 else: 1)

echo FS(A)
# echo FS(A,myCmp)  # this compiles fine

#[
/tmp/jarausch/.cache/nim/BUG_d/@mBUG.nim.c: In function 'NimMainModule':
/tmp/jarausch/.cache/nim/BUG_d/@mBUG.nim.c:185:69: error: expected expression before ')' token
  185 |  T2_ = FS__M7cQ7xfR9acKDe9cYix8OwcA(A__a1TOBMZ6yaU79afZ08aXS9cg, 6, );
      |                                                                     ^
Error: execution of an external compiler program 'x86_64-pc-linux-gnu-gcc -c  -w -fmax-errors=3   -I/usr/lib/nim -I/home/jarausch/Nim_My/Math -o /tmp/jarausch/.cache/nim/BUG_d/@mBUG.nim.c.o /tmp/jarausch/.cache/nim/BUG_d/@mBUG.nim.c' failed with exit code: 1
]#

nim -v

Nim Compiler Version 1.5.1 [Linux: amd64]
Compiled at 2021-03-16
Copyright (c) 2006-2021 by Andreas Rumpf

git hash: 48eab5370a5e731059a7337f702b2bc42a3c4b79
active boot switches: -d:release

[timotheecour]

please check whether you can minimize this without using generics

[HJarausch]

My programme was in error (I wished I got a sensible error message). If the programme is corrected to

proc FP[T](A: var openArray[T], myCmp : proc(x,y:T):int {.nimcall}): int =
  1

proc FS[T](A: var openArray[T], myCmp : proc(x,y:T):int {.nimcall} = system.cmp[T]): int =
  result= FP(A, myCmp)

const
  N= 6
  K= 3
var A :array[N,float]= [7.0,4,6,3,9,1]

func myCmp(x,y:float):int =
  (if x==y : 0 elif x<y : -1 else: 1)

echo FS(A)

it compiles and runs just fine.

[ghost]

Even if it's a mistake in the code Nim should output an error instead of making invalid C code :)