Parsing exception while using 'as' operator

[pawel1708hp]

I'm trying to use following expression:

string.IsNullOrEmpty(variable as string)

but it results with exception: DynamicExpresso.Exceptions.ParseException: ')' or ',' expected (at index 40).

Adding extra parenthesis as message suggests solves the issue, but the expression is obviously wrong then
string.IsNullOrEmpty(variable as string))

Seems there is something wrong with parser.

[metoule]

I think we don't support dynamic casts yet (the expr as Type expression). PRs welcome :)

[pawel1708hp]

Well, according to documentation it is supported ;)

[IAMJDA]

We have the exact issue since upgrading to a newer version. Expressions which worked before, now break.

[davideicardi]

It could be a regression. could you help us by telling us from which version it stopped working?

[IAMJDA]

Before: 2.8.1.0
After: 2.10.0.0

Test for As_Operator:
Assert.AreEqual(string.IsNullOrEmpty(a as string), target.Eval("string.IsNullOrEmpty(a as string)"));

[IAMJDA]

Manual bisect:

• 2.9.5 fails
• 2.9.4 works

#178 seems to be to blame

[metoule]

@IAMJDA thanks for narrowing it down! It's indeed a regression in the way the types are parsed: we don't reset the parser position properly if the type has no modifier. I'll need to ensure it's working for all the possible type modifiers. For example:

string?
string?[]
string?[][]
IEnumerable<string>
IEnumerable<string?[]>?[]

but it shouldn't take too long 🤞