Translate-c incorrectly translates address-of operator with fn ptr and obscure fn calls

[Rocknest]

This c source

#include <stdlib.h>
#include <stdint.h>

static int add(int a, int b) {
    return a + b;
}

int main(int argc, char **argv) {
    if ((&add)(1, 2) != 3) abort();
    if (add(3, 1) != 4) abort();
    if ((*add)(2, 3) != 5) abort();
    if ((**add)(7, -1) != 6) abort();
    if ((***add)(-2, 9) != 7) abort();

    int (*ptr)(int a, int b);
    ptr = add;
    
    if (ptr(1, 2) != 3) abort();
    if ((*ptr)(3, 1) != 4) abort();
    if ((**ptr)(2, 3) != 5) abort();
    if ((***ptr)(7, -1) != 6) abort();
    if ((****ptr(-2, 9) != 7) abort();

    uintptr_t addr1 = (uintptr_t) (add);
    uintptr_t addr2 = (uintptr_t) (&add);
    
    if (addr1 != addr2) abort();
    return 0;
}

incorrectly translated as

pub fn add(arg_a: c_int, arg_b: c_int) callconv(.C) c_int {
    var a = arg_a;
    var b = arg_b;
    return (a + b);
}
pub export fn main(arg_argc: c_int, arg_argv: [*c][*c]u8) c_int {
    var argc = arg_argc;
    var argv = arg_argv;
!   if ((&add).?(@as(c_int, 1), @as(c_int, 2)) != @as(c_int, 3)) abort();
    if (add(@as(c_int, 3), @as(c_int, 1)) != @as(c_int, 4)) abort();
!   if ((add).?(@as(c_int, 2), @as(c_int, 3)) != @as(c_int, 5)) abort();
!   if ((add).?(@as(c_int, 7), -@as(c_int, 1)) != @as(c_int, 6)) abort();
!   if ((add).?(-@as(c_int, 2), @as(c_int, 9)) != @as(c_int, 7)) abort();
    var ptr: ?fn (c_int, c_int) callconv(.C) c_int = undefined;
    ptr = add;
    if (ptr.?(@as(c_int, 1), @as(c_int, 2)) != @as(c_int, 3)) abort();
    if ((ptr).?(@as(c_int, 3), @as(c_int, 1)) != @as(c_int, 4)) abort();
    if ((ptr).?(@as(c_int, 2), @as(c_int, 3)) != @as(c_int, 5)) abort();
    if ((ptr).?(@as(c_int, 7), -@as(c_int, 1)) != @as(c_int, 6)) abort();
    if ((ptr).?(-@as(c_int, 2), @as(c_int, 9)) != @as(c_int, 7)) abort();
    var addr1: usize = @intCast(usize, @ptrToInt((add)));
!   var addr2: usize = @intCast(usize, @ptrToInt((&add)));
    if (addr1 != addr2) abort();
    return 0;
}

1. In C address-of operator on function name is ignored.
   (uintptr_t) (add) and (uintptr_t) (&add) are equivalent. This is a footgun protection against footgun of pointer casting a double pointer to a single pointer #1890

2. C allows to call functions in obscure ways. In addition to the default way name(args) there are:
   (&name)(args) and ( '*' n times name)(args).

Similarly to this dereference operator (n times) is ignored on function pointers.

[zuntrax]

I'm looking into this.