fix(#15784): ident rule for pat match was too strict #19501
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close scala#15784 Scala 2 allows backticked identifier and capital identifier in pattern match, but Scala 3 mistakenly prohibited them. For example, the following code is valid in Scala 2, ```scala List(42) match { case List(_, Rest @ _*) => Rest case List(_, `Rest` @ _*) => `Rest` _ => ??? } ``` whereas it resulted in `Not Found Rest` error in Scala 3. This is because the condition to detect wildcard pattern was so strict that it chose the wrong match arm; `case _ => ifExpr`.
sjrd
requested changes
Jan 22, 2024
tests/neg/i15784.scala
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| def i15784 = List(42) match | ||
| case List(_, Rest @ `a`) => Rest // error |
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NIT: please follow the standard 2-space indent in the test files as well:
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| def i15784 = List(42) match | |
| case List(_, Rest @ `a`) => Rest // error | |
| def i15784 = List(42) match | |
| case List(_, Rest @ `a`) => Rest // error |
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I addressed them.
09abbd6
sjrd
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Jan 22, 2024
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close #15784
Scala 2 allows backticked identifier and capital identifier in pattern match, but Scala 3 mistakenly prohibited them.
For example, the following code is valid in Scala 2,
whereas it resulted in
Not Found Resterror in Scala 3.This is because the condition to detect wildcard pattern was so strict that it chose the wrong match arm;
case _ => ifExpr.