Fix #3408 Implement SIP-27: Trailing Commas #3463
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Thanks a lot for your contribution @CucumisSativus ! For the import problem, you can try some changes in the parser as follows:
--- a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
+++ b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
@@ -1961,10 +1961,10 @@ object Parsers {
/** ImportSelectors ::= `{' {ImportSelector `,'} (ImportSelector | `_') `}'
*/
- def importSelectors(): List[Tree] =
- if (in.token == RBRACE) Nil
+ def importSelectors(): List[Tree] = {
+ val sel = importSelector()
+ if (in.token == RBRACE) sel :: Nil
else {
- val sel = importSelector()
sel :: {
if (!isWildcardArg(sel) && in.token == COMMA) {
in.nextToken()
@@ -1973,6 +1973,7 @@ object Parsers {
else Nil
}
}
+ }| trait ArgumentExprs1 { f(23, "bar", )(Ev0, Ev1) } // error // error | ||
| trait ArgumentExprs2 { f(23, "bar")(Ev0, Ev1, ) } // error // error | ||
| trait ArgumentExprs3 { new C(23, "bar", )(Ev0, Ev1) } // error // error | ||
| trait ArgumentExprs4 { new C(23, "bar")(Ev0, Ev1, ) } // error // error |
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It would be nice to avoid undefined identifiers so that we only get errors about trailing commas. Same for the code below.
Scanner implemented to accept trailing commas before new line Based on SI-4986 Allow trailing commas before newlines from scala repository
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hey @liufengyun i hope i resolved the issues you addressed + your fix to |
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| // Multi-line only cases: make sure trailing commas are only supported when multi-line | ||
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| trait ArgumentExprs1 { validMethod(23, "bar", )(Ev0, Ev1) } // error // error |
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What are the two errors emitted here? One is the invalid trailing comma. What is the other one?
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The first one is illegal start of simple expression. The second is as follow
5 |trait ArgumentExprs1 { validMethod(23, "bar", )(Ev0, Ev1) } // error // error
| ^
|too many arguments for method validMethod: (foo: Int, bar: String)(implicit ev0: foo.package.Ev0, ev1: foo.package.Ev1): Int
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LGTM, thanks a lot @CucumisSativus ! |
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Thank @liufengyun and @allanrenucci for your time :) |
Scanner implemented to accept trailing commas before new line, implementation form scala repo scala/scala#5245
There is one negative case which should fail, but does not
trait ImportSelectors { import foo.{ Ev0, Ev1, } }Would appreciate any help there
The rest seams to be working, but I would be glad if you could double check my tests