People, it's a popularity contest, you have to do somthing cool here.
Think about cool ways of breaking the code in most languages, not about validating for everyting!
Initially this challenge is NOT for esoteric languages. But I didn't disabled them as I expect voters to be fair enough to downvote answers based only on esoteric language syntax uniqueness.
It's not too broad. I thought about code golf tag, but desided that it will be unnessesary limitation for the answers. I expect anwsers to be short and exploiting some language feature.
By the way, I have an interesting solution for VB.NET and it is shorter than 8 chars :)
Write a statement that multiplies the (integer) variable by 10 and assigns result to the same variable. If your language has no integer type, you may assume that the value is an integer not greater then some limit (you can specify this limit yourself, but it defenitly have to be adequate).
The initial and resulting values have to be number. Using string as one of them (or both) is forbidden.
But you don't want the code to be protable, so you are going to write it in such way, that the code is valid for as few programming languages as possible. Ideally in the only language.
You have variable
int x = 77;
and the answer is
x *= 10;
Declaration is not the part of the answer, only
x *= 10; is.
It's defenity a bad answer in this challenge.
Just drop a semicolon to cut off C, C++, C# and Java, but VB.NET appears in this case.
Scoring system: it's a popularity contest. For now I'll define the answer score as number of votes, but I'll keep a right to change scoring system by including number of languages into it.
So you have to provide a statement and list of languages (ideally one language) it is valid in.