Improve type inference of quote pattern splices #8695
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Infer higher bound for type splices. This means that when type information is not given the pattern should match all term that could fit in this hole.
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flipBottom only special-cases Nothing, but the same issue could reoccur with a different bound like >: Null. I'm not sure how the example above works anyway, when you write:
case '{ println(f($y)) } => yshouldn't this be expanded to:
case '{ println(f[$t]($y)) } => yAnd that way, any println(f[...](...)) call will match, no matter the type argument ?
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That is the current workaround, but it seems hard to expand it while typing it. At some point, this should be tried.
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This is just meant as a patch for a relatively common code pattern. I'm working on the side on implementing the whole pattern desugaring/typing logic which might help us with those tricky expansions.
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That would be great! I might have situations with odd types.
nicolasstucki
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It's really great to be able to rely on normal Scala syntactic sugar when doing quoted pattern matching. I am currently in the process of training several students in Scala in order to be able to help me port the Quill parser to Dotty and their first question is "Why can't we depend on all of Scala's type inferencing when matching quoted blocks?" |
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It is just an artefact of the current implementation. I'm working on improving this. |
Infer higher bound for type splices. This means that when type information is not given
the pattern should match all terms that could fit in this hole.
These are a source of buggy patterns that look fine but only match when the content is of type
Nothing(virtually never). This is never the intent of such code.