Increment and Decrement expressions are disassembled incorrectly

[Stevie-O]

The Increment and Decrement expression types are diassembled like pre-increment/pre-decrement operators, but these operators are really only the equivalent of operand + 1 and operand - 1.

This expression:

var x =
    Expression.Variable(typeof(byte), "x");
        Expression.Assign(
            x,
            Expression.Convert(
	        Expression.Increment(
	            Expression.Convert(x, typeof(int))
	        ),
	    typeof(byte)
        )
    )
    .ToReadableString()
    .Dump();

outputs x = (byte)++(int)x, when x = (byte)((int) + 1) is the correct interpretation.

In idiomatic C#, this is x += 1 for a variable of type byte.

[SteveWilkes]

Hi,

Thanks for the feedback!

Looking at the documentation for Expression.Increment() (and the documentation for Decrement() is basically the same), and given that Expression has separate PreIncrement() / PostIncrement() / PreDecrement() / PostDecrement() factory methods which represent (and translate to) the pre and post ++ / -- operators, maybe Increment() and Decrement() should be translated to x + 1 / x - 1?

In fact the code sample includes a comment stating "The value of the variable did not change, because the expression is functional", which pretty much makes it explicit.

What d'you think?

Cheers,

Steve

[SteveWilkes]

This is fixed in the v3.0 branch, which will be releasing in the next week or so.

Thanks again!

[SteveWilkes]

This fix is part of the v3.0-preview1 package, which is now on NuGet.

Thanks!

[SteveWilkes]

This is part of the full v3 release, which is now available on NuGet. Cheers!