When casting, a procedure is not properly selected when two procedures with
different signatures have the same name.
The examples below use types from the __iup__ and __nimpy__ libraries. I
included all the relevant parts from the libraries and shortened the code a
bit:
# types imported from the iup library
type
Ihandle = object
PtrIhandle* = ptr Ihandle
Icallback* = proc (arg: PtrIhandle): cint {.cdecl.}
# types imported from the nimpy library
type
PPyObject* = distinct pointer
PyObject* = ref object
rawPyObj: PPyObject
Run
# mymodule.nim
proc turn_on*(bulb: PyObject) =
discard
Run
# main.nim
import mymodule
proc turn_on(button: PtrIhandle): cint =
discard
def main() =
#[
some code
]#
# Setting a callback for a button from the iup library
btn_on.setCallback("ACTION", cast[Icallback](turn_on)) # Error line
Run
The following error is thrown when compiling with nim c main.nim:
main.nim(9, 34) Error: expression cannot be cast to Icallback=proc (arg:
PtrIhandle): cint{.cdecl.}
Run
The compiler selects the mymodule.turn_on proc instead of main.turn_on in the
line:
btn_on.setCallback("ACTION", cast[Icallback](turn_on))
Run
First off, I didn't know that you can reference the module you are inside in.
Cool. I tried it, and it works:
btn_on.setCallback("ACTION", cast[Icallback](main.turn_on))
Run
But my feeling is that the compiler should know which is the correct procedure
based on the signature or at least say that it doesn't know which one it should
pick.
Should I report this issue or am I missing something?
