Linter: Lint for empty statements (was Linter should catch `if (foo);`)

[Hixie]

I just got caught by the following code:

  if (complicated.expression.foo());
    bar();

It would be great if the linter could catch cases of an "if" block doing nothing.

[alexeieleusis]

Some code styles prevent this by requiring if statements to always have bodies. Don't you like that approach?

[Hixie]

How would that stop this case?

if (complicated.expression.foo()); {
    bar();
}

...has the same issue.

[pq]

If I'm not missing something I think both of those cases are essentially the same at the AST level: the rub is that the if has an empty then statement.

Incidentally, using a formatter really helps make these cases more obvious as dartftmt wrestles your examples into these respectively.

  if (complicated.expression.foo()) ;
  bar();

if (complicated.expression.foo()) ; 
{
    bar();
}

But anyway, I think a rule checking for empty then statement is totally reasonable.

Curious if @bwilkerson cares to chime in? It's early. First cup of coffee, so I'm sure I'm overlooking something!

☕

[pq]

FWIW: I'm playing with an implementation. (We can always toss it if we come to another conclusion on it's value.)

[bwilkerson]

Personally, I think it's always questionable to have an empty statement, so I would just flag empty statements where ever they occur. I'm kind of surprised that we don't already have that somewhere.

[pq]

I'm with Brian.

[Hixie]

Totally agree that we should just catch empty statements.

(And yeah, a formatter would help here too. But that assumes you look at the formatted code...)