error or not error ?

[DirectuX]

Should this code raise an error ?

uses "console"

dim myvar as DWord = 1
myvar = - myvar
printl myvar
WaitKey

myvar is declared as an unsigned variable. Why is it allowed to compute something below 0 ?

Edit: All the same, if you declare

• a variable as byte and assign a value outside the 0-255 range
• a variable as boolean that isn't %true nor %false

Regarding this previous question and the last Petr's blog page,
is there a list of all errors caught by thinBasic ?