On 08/21/2016 07:12 AM, Shachar Shemesh wrote:
During static analysis, keep both the "most expanded" and the "least expanded" type of the expression parsed so far. "Least expanded" is the largest type actually used in the expression.
What's "most expanded"?
Upon use of the value, resolve which type to actually use for it. If the use type requests a type between least and most, use that type for evaluating the entire expression. If the use requests a type outside that range, use the one closest (and, if the use is below the range, complain about narrowing conversion).
So when only ubytes are involved, all calculations would be done on ubytes, no promotions, right? There are cases where that would give different results than doing promotions.
Consider `ubyte(255) * ubyte(2) / ubyte(2)`. If the operands are promoted to a larger type, you get 255 as the result. If they are not, you have the equivalent of `ubyte x = 255; x *= 2; x /= 2;` which gives you 127.
