Reject char literal of raw newline

[som-snytt]

Don't allow char literal to span a natural line
ending, but do allow '\u000A' to mean '\n'.
The spec was updated to reflect that meaning,
and the direction is to eliminate Unicode escapes
outside quotes.

Update the test rig so that // anypos-error can be
used to match any position, since the test cannot
be expressed on one line with a trailing comment.

Forward port of fix on 2.12.

scala/scala@d7547cb

[dottybot]

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[som-snytt]

Double checking that it's not possible to write the test with

val c = '// error
'

I noticed

scala> '//
1 |'//
  |^
  |symbol literal '// is no longer supported,
  |use a string literal "//" or an application Symbol("//") instead,
  |or enclose in braces '{//} if you want a quoted expression.

scala> x_//
1 |x_//
  |^^^^
  |Not found: x_

It's not obvious that these are different with respect to tokenization, except literal vs identifier.

Scala 2 had a ticket IIRC for double slash in a name. I can't find it.

[som-snytt]

/rebuild

[som-snytt]

Not sure how to communicate with do-bo.

The restart button on drone is disabled.

[OlivierBlanvillain]

@som-snytt you can push an empty commit or rebase + force push

[martijnhoekstra]

Why not though?

[som-snytt]

Rebased and fixed conflict with whitespace change.

The controversial part is support for // anypos-error in tests for the edge case where the error comment alters the test.

[abgruszecki]

Hey there, thanks for the PR!
Two questions:

1. is there any specific reason why ''' is now invalid syntax when it was valid before? It seems to me rejecting char lit of raw newline doesn't require rejecting ''' as a valid char lit.
2. is there any need for both anypos-error and a checkfile?

[som-snytt]

The scala 2 ticket and PR say the spec disallowed it, and the ticket quotes it, but I can't find it at the moment. (or after looking for a half hour)

scala/bug#10133
scala/scala#5629

The test rig requires the error comment? Everything that happened before the pandemic feels like a long time ago, and in fact I was getting sick that week, so I don't quite recall. The check file shows what error message was produced, not only that there was an error. My initial expectation was that the error comment would include the expected error text, perhaps as a regex.

[abgruszecki]

I was a bit ill as well when the lockdowns hit. Hope everything's all right on your side.

Reg. the PR: I was under the impression that the test rig required either // error comments or checkfiles, not both at the same time; and ofc adhering to spec is a good reason for forbidding '''. Merging now.