Wrong pattern must be a value

[tgodzik]

Found an issue when working on scalameta/metals#4896

${ success.tree.asExprOf[InterpolationConverterType] }

looks like an issue with Scala 3 dialect

[kitbellew]

@tgodzik can you repro? I added to MacroSuite.scala

    runTestAssert[Stat](
      "${ success.tree.asExprOf[InterpolationConverterType] }"
    )(
      ...
    )

and it didn't have any parsing problems.

[Atry]

I think it's a Scala 3 splice expression at https://github.com/Atry/html.scala/blob/0df608834dcf0dcdcae32d60f23a4c9560ddbf0a/html/src/main/scala/com/yang_bo/html/package.scala#L193

[tgodzik]

@tgodzik can you repro? I added to MacroSuite.scala

    runTestAssert[Stat](
      "${ success.tree.asExprOf[InterpolationConverterType] }"
    )(
      ...
    )

and it didn't have any parsing problems.

I wanted to take a look, but I didn't have time yet. @Atry is right, it fails there.

[sirthias]

I tripped over this same issue in https://github.com/sirthias/borer.
A parser bug is a real pain since it completely kills the build and cannot be fenced off // format: OFF.
For now I had to completely exclude the affected files with project.excludePaths = [ ... ].

[kitbellew]

I tripped over this same issue in https://github.com/sirthias/borer. A parser bug is a real pain since it completely kills the build and cannot be fenced off // format: OFF. For now I had to completely exclude the affected files with project.excludePaths = [ ... ].

can you please provide a small reproducible example? we haven't made progress on this because the original example does not fail in our tests.

[sirthias]

It's a weird issue, also for me.
It only happened on complete, clean rebuilds, not on subsequent runs.
I'll try once more to isolate it.

[kitbellew]

@tgodzik @sirthias @Atry can you provide the link to a failing file and the line number in that file? Whether on clean builds or every time, doesn't matter.

pattern must be a value appears in the parser code only once, when parsing an expression like this:

foo match
  case bar[baz] => // parser expects parentheses after brackets

(or any other pattern expression which looks like bar[baz], such as in for { pattern <- ... }). So, need to know not only the exact expression but its full context.