Error seen on parsing a case class nested in an object definition with Scala 3.

[sageserpent-open]

Commit of tree-sitter-scala you tested this on

dd02e51

A code sample showing the error

package com.sageserpent.kineticmerge.core

object Merge:

  case class Location(runIndex: Int, locationInRun: String):
  end Location

end Merge

Show the error node

compilation_unit (0, 0) - (8, 0)
  package_clause (0, 0) - (0, 41)
    package (0, 0) - (0, 7) "package"
    package_identifier (0, 8) - (0, 41)
      identifier (0, 8) - (0, 11) "com"
      . (0, 11) - (0, 12) "."
      identifier (0, 12) - (0, 23) "sageserpent"
      . (0, 23) - (0, 24) "."
      identifier (0, 24) - (0, 36) "kineticmerge"
      . (0, 36) - (0, 37) "."
      identifier (0, 37) - (0, 41) "core"
  object_definition (2, 0) - (7, 0)
    object (2, 0) - (2, 6) "object"
    identifier (2, 7) - (2, 12) "Merge"
    template_body (2, 12) - (7, 0)
      : (2, 12) - (2, 13) ":"
      class_definition (4, 2) - (4, 59)
        case (4, 2) - (4, 6) "case"
        class (4, 7) - (4, 12) "class"
        identifier (4, 13) - (4, 21) "Location"
        class_parameters (4, 21) - (4, 59)
          ( (4, 21) - (4, 22) "("
          class_parameter (4, 22) - (4, 35)
            identifier (4, 22) - (4, 30) "runIndex"
            : (4, 30) - (4, 31) ":"
            type_identifier (4, 32) - (4, 35) "Int"
          , (4, 35) - (4, 36) ","
          class_parameter (4, 37) - (4, 58)
            identifier (4, 37) - (4, 50) "locationInRun"
            : (4, 50) - (4, 51) ":"
            type_identifier (4, 52) - (4, 58) "String"
          ) (4, 58) - (4, 59) ")"
      ERROR (4, 59) - (5, 14)
        : (4, 59) - (4, 60) ":"
  end (7, 0) - (7, 3) "end"
  _end_ident (7, 4) - (7, 9) "Merge"

Incidentally, omitting the end marker for the case class does not avoid the error.

What do you expect the tree to look like

Omitting the colon trailing after the nested case-class definition yields a correct parse, here I have substituted a trailing blank character for the colon...

compilation_unit (0, 0) - (8, 0)
  package_clause (0, 0) - (0, 41)
    package (0, 0) - (0, 7) "package"
    package_identifier (0, 8) - (0, 41)
      identifier (0, 8) - (0, 11) "com"
      . (0, 11) - (0, 12) "."
      identifier (0, 12) - (0, 23) "sageserpent"
      . (0, 23) - (0, 24) "."
      identifier (0, 24) - (0, 36) "kineticmerge"
      . (0, 36) - (0, 37) "."
      identifier (0, 37) - (0, 41) "core"
  object_definition (2, 0) - (7, 0)
    object (2, 0) - (2, 6) "object"
    identifier (2, 7) - (2, 12) "Merge"
    template_body (2, 12) - (7, 0)
      : (2, 12) - (2, 13) ":"
      class_definition (4, 2) - (4, 59)
        case (4, 2) - (4, 6) "case"
        class (4, 7) - (4, 12) "class"
        identifier (4, 13) - (4, 21) "Location"
        class_parameters (4, 21) - (4, 59)
          ( (4, 21) - (4, 22) "("
          class_parameter (4, 22) - (4, 35)
            identifier (4, 22) - (4, 30) "runIndex"
            : (4, 30) - (4, 31) ":"
            type_identifier (4, 32) - (4, 35) "Int"
          , (4, 35) - (4, 36) ","
          class_parameter (4, 37) - (4, 58)
            identifier (4, 37) - (4, 50) "locationInRun"
            : (4, 50) - (4, 51) ":"
            type_identifier (4, 52) - (4, 58) "String"
          ) (4, 58) - (4, 59) ")"
      end (5, 2) - (5, 5) "end"
      _end_ident (5, 6) - (5, 14) "Location"
  end (7, 0) - (7, 3) "end"
  _end_ident (7, 4) - (7, 9) "Merge"

Furthermore, moving the case class definition to the top level gives a correct parse even with the trailing colon:

package com.sageserpent.kineticmerge.core

case class Location(runIndex: Int, locationInRun: String):
end Location

compilation_unit (0, 0) - (4, 0)
  package_clause (0, 0) - (0, 41)
    package (0, 0) - (0, 7) "package"
    package_identifier (0, 8) - (0, 41)
      identifier (0, 8) - (0, 11) "com"
      . (0, 11) - (0, 12) "."
      identifier (0, 12) - (0, 23) "sageserpent"
      . (0, 23) - (0, 24) "."
      identifier (0, 24) - (0, 36) "kineticmerge"
      . (0, 36) - (0, 37) "."
      identifier (0, 37) - (0, 41) "core"
  class_definition (2, 0) - (4, 0)
    case (2, 0) - (2, 4) "case"
    class (2, 5) - (2, 10) "class"
    identifier (2, 11) - (2, 19) "Location"
    class_parameters (2, 19) - (2, 57)
      ( (2, 19) - (2, 20) "("
      class_parameter (2, 20) - (2, 33)
        identifier (2, 20) - (2, 28) "runIndex"
        : (2, 28) - (2, 29) ":"
        type_identifier (2, 30) - (2, 33) "Int"
      , (2, 33) - (2, 34) ","
      class_parameter (2, 35) - (2, 56)
        identifier (2, 35) - (2, 48) "locationInRun"
        : (2, 48) - (2, 49) ":"
        type_identifier (2, 50) - (2, 56) "String"
      ) (2, 56) - (2, 57) ")"
    template_body (2, 57) - (4, 0)
      : (2, 57) - (2, 58) ":"
      end (3, 0) - (3, 3) "end"
      _end_ident (3, 4) - (3, 12) "Location"

Given that there is a template body in this example, that should probably appear in the expected correct parse, so take the first expected output with a pinch of salt.

Where are you experiencing this error?

Difftastic, release 0.49 with a subtree merge of Treesitter at dd02e51

[susliko]

@sageserpent-open Thanks for reporting!