Merge pull request #5245 from dwijnand/trailing-commas

SI-4986 The glorious return of Comma McTraily

1 files changed, 11 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
index a8cc7f91c2..99713451ac 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
@@ -386,6 +386,17 @@ trait Scanners extends ScannersCommon {
           next copyFrom this
           this copyFrom prev
         }
+      } else if (token == COMMA) {
+        // SIP-27 Trailing Comma (multi-line only) support
+        // If a comma is followed by a new line & then a closing paren, bracket or brace
+        // then it is a trailing comma and is ignored
+        val saved = new ScannerData {} copyFrom this
+        fetchToken()
+        if (afterLineEnd() && (token == RPAREN || token == RBRACKET || token == RBRACE)) {
+          /* skip the trailing comma */
+        } else if (token == EOF) { // e.g. when the REPL is parsing "val List(x, y, _*,"
+          /* skip the trailing comma */
+        } else this copyFrom saved
       }
 
 //      print("["+this+"]")