[PATCH] D26943: [CodingStandards] Add style guide rule about "if" statements and loops.

[Reid Kleckner via llvm-commits]

rnk added a comment.

>> Although, for really simple cases it's probably fine to omit them:
>> 
>>   if (auto Foo = bar())
>>     for (auto Baz : Foo.stuff())
>>       bazIt(Baz);
> 
> These types of constructs are one of my favorite parts of idiomatic LLVM code. I'd hate to lose them.

I'm sympathetic to this idiom, but I can't come up with an easy way to write a rule to allow it:

  for (Foo *f : foos)
    if (f->isSomething())
      return true;
  return false;

I also don't like it when it gets to three blocks.

  for (Foo *f : foos)
    if (auto *b = dyn_cast<Bar>(f->getBar()))
      if (b->isBaz())
        return true;
  return false;

It's too clever.

I'd rather have an easy rule of thumb that requires this:

  for (Foo *f : foos) {
    if (f->isSomething())
      return true;
  }
  return false;

I've also seen this before, and I want to make sure I don't see it again:

  for (Foo *f : foos)
    if (f->isSomething()) {
      stmt1();
      stmt2();
    }


https://reviews.llvm.org/D26943