[BUG] Unsigned integer casting overflowing as if signed when using `int()` or `UInt32()`

[fnands]

[BUG] Unsigned integer casting overflowing as if signed when using `int()` or `UInt32()`

[soraros]

Smaller repro:

fn main():
    print(int(UInt8(128)))  # prints -128

It's very curious that the following runs fine:

fn main():
  var n = UInt8(128)
  print(n)       # prints 128
  print(int(n))  # prints 128

[fnands]

Smaller repro:

fn main():
    print(int(UInt8(128)))  # prints -128

Similarly, running:

  var a: UInt32 = 129

  print(int(a.cast[DType.uint8]()))

in the REPL returns 129.

Running:

def main():
    var a: UInt32 = 129

    print(int(a.cast[DType.uint8]()))

main()

In the REPL returns -127

[fnands]

Just tested on nightly and behaviour is identical.
Nightly version: mojo 2024.6.1705 (79838f00)

[soraros]

Related to #2860 and #3045.

The 1 is caused by implicit conversion. UInt32(...) doesn't do what you think it does.

[fnands]

So just to be clear:

The var vs alias differences seem to only appear when reading a value from a table.

So there might be two issues: the table one and the int() one.