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Add an error message for incorrect sequence wildcard position Parsers.scala:1425 and Parsers.scala:1079 #1698

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Merged
merged 1 commit into from
Nov 14, 2016
Merged

Add an error message for incorrect sequence wildcard position Parsers.scala:1425 and Parsers.scala:1079 #1698

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4 changes: 2 additions & 2 deletions src/dotty/tools/dotc/parsing/Parsers.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -1076,7 +1076,7 @@ object Parsers {
val uscoreStart = in.skipToken()
if (isIdent(nme.raw.STAR)) {
in.nextToken()
if (in.token != RPAREN) syntaxError("`_*' can be used only for last argument", uscoreStart)
if (in.token != RPAREN) syntaxError(SeqWildcardPatternPos(), uscoreStart)
Typed(t, atPos(uscoreStart) { Ident(tpnme.WILDCARD_STAR) })
} else {
syntaxErrorOrIncomplete(IncorrectRepeatedParameterSyntax())
Expand Down Expand Up @@ -1424,7 +1424,7 @@ object Parsers {
// `x: _*' is parsed in `ascription'
if (isIdent(nme.raw.STAR)) {
in.nextToken()
if (in.token != RPAREN) syntaxError("`_*' can be used only for last argument", wildIndent.pos)
if (in.token != RPAREN) syntaxError(SeqWildcardPatternPos(), wildIndent.pos)
atPos(wildIndent.pos) { Ident(tpnme.WILDCARD_STAR) }
} else wildIndent
case LPAREN =>
Expand Down
23 changes: 23 additions & 0 deletions src/dotty/tools/dotc/reporting/diagnostic/messages.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -789,4 +789,27 @@ object messages {
val msg = "unreachable code"
val explanation = ""
}

case class SeqWildcardPatternPos()(implicit ctx: Context) extends Message(31) {
val kind = "Syntax"
val msg = "`_*' can be used only for last argument"
val explanation = {
val code =
"""def sumOfTheFirstTwo(list: List[Int]): Int = list match {
| case List(first, second, x:_*) => first + second
| case _ => 0
|}"""
hl"""|Sequence wildcard pattern is expected at the end of an argument list.
|This pattern matches any remaining elements in a sequence.
|Consider the following example:
|
|$code
|
|Calling:
|
|${"sumOfTheFirstTwo(List(1, 2, 10))"}
|
|would give 3 as a result"""
}
}
}