[cfe-dev] Can't use sizeof ( typeof ( <vla> ))

[Friedman, Eli via cfe-dev]

On 12/1/2016 2:13 AM, Paulo Matos wrote:
>
> On 22/11/16 21:44, Friedman, Eli wrote:
>> The way it should work is that there are three calls to
>> TransformToPotentiallyEvaluated: the first time, we're calling on the
>> typeof, and it's unevaluated.  The second time, we're calling it on the
>> sizeof(), and it's potentially evaluated.  The third time is a recursive
>> call: in the process of transforming the sizeof(), we make a new
>> typeof() expression, and call TransformToPotentiallyEvaluated on that;
>> at that point, it should be potentially-evaluated.  (Yes, this is
>> terribly inefficient, but it's a rare situation anyway.)
>>
> Apologies, only just managed to get back on this. I assume you're
> suggesting a solution, not how it's implemented.

This is what's already implemented for sizeof() on a expression.  We 
just don't do it properly for sizeof() on a type, I think.  There are 
two functions named Sema::CreateUnaryExprOrTypeTraitExpr; compare the 
version which takes a type to the version which takes an expression.

-Eli

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