[cfe-dev] [Clang 3.0] Inconsistent warnings about assignment in a condition

[John McCall]

On Mar 16, 2012, at 12:44 AM, Alexei Sholik wrote:
> I can't find a way to make Clang _always_ trigger warnings about
> assignment inside a condition. When I create a new project (Mac or
> iOS) in Xcode 4.3.1 and compile it, the following code does not
> trigger any warnings:
> 
> - (id)init
> {
>    if (self = [super init]) {
>        // ...
>    }
>    return self;
> }

We wanted to enable -Wparentheses by default, but we got a lot of pushback
over this specific idiom (particularly since Apple puts out example code
with this verbatim), so we moved it to a subgroup -Widiomatic-parentheses
that is not enabled by default.  If you specifically enable -Wparentheses
instead of relying on the default behavior, you should see warnings about
this.

> BUT, in the same project I don't get any warnings in the following case:
> 
>        if (self.uid = 11) {
>            // ...
>        }
> 
> Is this behavior expected? Which flag should I use in order for the
> compiler to catch this case too?

This is an oversight caused by a recent refactor;  please file a bug.

John.