Disallow local term references in staged types #16362
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nicolasstucki
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| @@ -206,6 +206,8 @@ class PCPCheckAndHeal(@constructorOnly ictx: Context) extends TreeMapWithStages( | |||
| tryHeal(prefix.symbol, tp, pos) | |||
| case _ => | |||
| mapOver(tp) | |||
| case tp @ TermRef(NoPrefix, _) if !tp.symbol.isStatic && level > levelOf(tp.symbol) => | |||
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why do we check level > here but level != in healTypeOfTerm?
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In healTypeOfTerm we are looking for terms that are used in other stages. Terms must be used at the same stage they are defined, hence the level !=.
For types the rules are a bit different. For types in general it is always safe to use the type in a previous stage and one needs a type Type[T] for generic types if it is used in a future stage. This is in general where the > comes in for type. But in this particular case, we have a type reference to a local variable that will not exist in the next stage and we cannot create a valid Type[T] for it. Therefore it emmits an error.
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Thanks for the explanation, I think it'd be helpful to add something like that as a comment in the code
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Co-authored-by: Guillaume Martres <smarter@ubuntu.com>
Fixes #15917
Fixes #16355