Dot operators with type mismatch, shows assertion instead of compiler error

[jtiai]

The following code doesn't compile and causes unhandled exception:

Example

{.experimental: "dotOperators".}

type
    Flag = enum
        A

    Flags = set[Flag]

template `.=`*(flags: Flags, key: Flag, val: bool) =
    if val: flags.incl key else: flags.excl key

var flags: Flags

flags.A = 123

Current Output

....fatal.nim(53)            sysFatal
Error: unhandled exception: semcall.nim(233, 18) `nArg != nil`  [AssertionDefect]

Expected Output

Compiler provides meanful error message or compiles.

Possible Solution

If flags.A = 123 is written as flags.A = bool(123) code compiles as expected.

$ nim -v
Nim Compiler Version 1.4.6 [Linux: amd64]
# make sure to include the git hash if not using a tagged release

[beef331]

As I mentioned in the realtime chat this is not due to the bool, it seems to be a dot operators with type mismatch bug.
This code shouldnt compile either, since you're passing an int as a bool and Nim doesnt implictly convert.
You can do the following and it'll work fine for you.

{.experimental: "dotOperators".}

type
    Flag = enum
        A

    Flags = set[Flag]

template `.=`*(flags: Flags, key: Flag, val: int | bool) =
    if val.bool: flags.incl key else: flags.excl key

var flags: Flags

flags.A = 123

[metagn]

Now gives

(14, 9) Error: undeclared field: 'A=' for type in.Flags [type declared in (7, 5)]

which seems reasonable?