System.OverflowException in unchecked block of C#

Question

(This question already has answers here): question from:https://stackoverflow.com/questions/66067417/system-overflowexception-in-unchecked-block-of-c-sharp

Answer 1

From the C# draft specification on integer division:

If the left operand is the smallest representable int or long value and the right operand is -1, an overflow occurs. In a checked context, this causes a System.ArithmeticException (or a subclass thereof) to be thrown. In an unchecked context, it is implementation-defined as to whether a System.ArithmeticException (or a subclass thereof) is thrown or the overflow goes unreported with the resulting value being that of the left operand.

I'm not sure where Microsoft lists its choices for implementation-defined behavior, but apparently they chose the first option here.

This and other implementation-defined or undefined behavior is listed in Annex B of ECMA-334. The draft specification above is updated more recently, but it seems to lack this annex.