Fix type error

Author: odersky

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -2170,7 +2170,7 @@ object Parsers {
                 // is not supported by Scala2.x
               report.errorOrMigrationWarning(
                 s"This syntax is no longer supported; parameter needs to be enclosed in (...)${rewriteNotice()}",
-                Span(start, in.lastOffset))
+                source.atSpan(Span(start, in.lastOffset)))
             in.nextToken()
             val t = infixType()
             if (sourceVersion == `3.1-migration`) {