Attempt at fixing Applications.scala:95 #1589
#3780
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dottybot
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Jan 9, 2018
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I signed the CLA. Should I open a new PR ? |
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@aesteve You can update the PR (e.g. by force push), and it will re-trigger the CI. |
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| |The return type of an extractor should be chosen as follows: | ||
| | - If it is just a test, return a ${"Boolean"}. For instance ${"case even()"} | ||
| | - If it returns a single sub-value of type ${s"$resultClassName"}, return an ${s"Option[$resultClassName]"} | ||
| | - If you want to return several sub-values ${"T1,...,Tn"}, group them in an optional tuple ${"Option[(T1,...,Tn)]"}. |
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This is not telling the full story, we also need to mention option-less pattern matching
and talk about unapplySeq.
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I believe unapplySeq has been deprecated in #3747
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By the way, this is a duplicate of #3501. |
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I believe a lot more work needs to be done on good unapply error messages. That work has to be in the Typer checker, which has to become better at finding root causes of unapply errors. Adding a fixed error message for the failure would make things more complicated at the present time |
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First try at implementing an error message, please tell me if I'm doing a mistake in some way.
Especially :
val kind = "Reference"the right kind of errorexplainpartunapplySeq?Thanks a lot for the review.