search for: exists_and_isa

...he existing "_or_null" varieties, i.e., "cast_or_null" and "dyn_cast_or_null". They accept a null and propagate it. In the "isa" case, it would accept a null and propagate it as false. > > not_null_and_isa<T> would seem a better fit, or maybe exists_and_isa<T>. > > That said, I'm not sure sure we need a special API for this. Are > expensive calls used in the way you describe really common? > I've only been looking at the ones involving method calls, but it's not too common. Perhaps a dozen in clang/lib -- haven't r...

...ack, > which may be null. isa<> is precondition check, so it "reads" > differently to me. If I were to see: > > if (isa_or_null<T>(var)) { > ... > } > > I would think, "Ok, the body is fine if var is null." > > Instead: > > if (exists_and_isa<T>(var)) { > ... > } > > This tells me that the body expects a non-null value. > > > > That said, I'm not sure sure we need a special API for this. Are > > > expensive calls used in the way you describe really common? > > > > I've only...

...>>> differently to me. If I were to see: >>> >>> if (isa_or_null<T>(var)) { >>> ... >>> } >>> >>> I would think, "Ok, the body is fine if var is null." >>> >>> Instead: >>> >>> if (exists_and_isa<T>(var)) { >>> ... >>> } >>> >>> This tells me that the body expects a non-null value. >>> >>> > > That said, I'm not sure sure we need a special API for this. Are >>> > > expensive calls used in the way you d...

...;>>> if (isa_or_null<T>(var)) { >>>>> ... >>>>> } >>>>> >>>>> I would think, "Ok, the body is fine if var is null." >>>>> >>>>> Instead: >>>>> >>>>> if (exists_and_isa<T>(var)) { >>>>> ... >>>>> } >>>>> >>>>> This tells me that the body expects a non-null value. >>>>> >>>>> > > That said, I'm not sure sure we need a special API for this. Are >>>&...

I'd like to propose adding `isa_or_null<>` to replace the following usage pattern that's relatively common in conditionals: var && isa<T>(var) =>> isa_or_null<T>(var) And in particular when `var` is a method call which might be expensive, e.g.: X->foo() && isa<T>(X->foo()) =>> isa_or_null<T>(X->foo()) The