Make sure language imports are detectable syntactically #11193
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liufengyun
approved these changes
Jan 31, 2021
| case Some(bv) => bv | ||
| case None => | ||
| var c = ctx.outer | ||
| while c.importInfo eq ctx.importInfo do c = c.outer |
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Minor: refactor the logic above into a method?
class Context(...):
/** Returns an outer context that introduces an import clause
*
* For a returned context `ctx`, `ctx.isImportContext == true`.
*/
def outerImportContext: Option[Context] = ???There was a problem hiding this comment.
As long as it's used only in one place I think it's better to leave it local
| case None => | ||
| var c = ctx.outer | ||
| while c.importInfo eq ctx.importInfo do c = c.outer | ||
| (c.importInfo != null) && c.importInfo.featureImported(feature)(using c) |
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Is it possible that c == null here, when we get to the very 1st context?
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No, because we will hit NoContext first
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But we have NoContext.outer == null. So the invariant here seems to be that we never hit NoContext.
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Ah yes, better make that explicit.
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Actually, NoContext has a null importInfo, so that will stop the recursion.
Make sure that something is a language import if and only if it
looks like one. i.e. is of one of the forms
import language.xyz
import scala.language.xyz
import _root_.scala.language.xyz
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Make sure that something is a language import if and only if it
looks like one. i.e. is of one of the forms
This is a pre-requisite for using language imports also during parsing, where we cannot resolve imports.
Using language imports during parsing can make the parser more robust by never considering possibilities that are not enabled bu a language import. For instance, we do not need to get confused with postfix operators.