Fix #8715: enforce syntax for _* #8732
Conversation
Previously we didn't check that _* is indeed the last argument, checking for ")" is not enough, as ")" may be the closing parenthsis of a nested pattern.
Previous only typing errors related to _* are annotated, now we also have parsing errors related to _*. Fix test
The code `text format (args : _*)` is invalid by Dotty syntax, we tolerate it for migration from Scala2.
We are not compiling stdlib with `-source 3.0-migration`, thus we need to change the syntax.
There was a problem hiding this comment.
The changes look correct. But I do not like that they add extra state to the parser. In this case, I believe we can get around it by adding a new value InArgumentList to Location. location values are propagated to ascription where we can check for it. They are not propagated to simplePatterm but I think we can leave the old incomplete check there as long a we warn that this is no longer supported.
| @@ -2009,7 +2017,14 @@ object Parsers { | |||
| val uscoreStart = in.skipToken() | |||
| if (isIdent(nme.raw.STAR)) { | |||
| in.nextToken() | |||
| if (in.token != RPAREN) syntaxError(SeqWildcardPatternPos(), uscoreStart) | |||
| if in.token != RPAREN || !inArguments && sourceVersion.isAtLeast(`3.1`) then | |||
| syntaxError(SeqWildcardPatternPos(), uscoreStart) | |||
There was a problem hiding this comment.
Maybe be more aggressive and demand this for 3.0? In any case, we should do migration warning and it would be nice to also offer a rewrite.
There was a problem hiding this comment.
In fact, I believe the warning that this is no longer supported is more important than the error that it's in the wrong place. The theory is that any code that has xs @ _* will have already been compiled by Scala 2 (in most cases, at least)
|
Thanks for the tip @odersky , I'll try the suggested fix. |
|
Close in favor of #8753, which is more elegant. |
Fix #8715: enforce syntax for _*
Previously we didn't check that _* is indeed the last argument,
checking for ")" is not enough, as ")" may be the closing parenthsis
of a nested pattern.