Fix: ufcs integer lexing (#912)

fixes #911

Author: dvdvgt

effekt/shared/src/main/scala/effekt/Lexer.scala

@@ -340,7 +340,10 @@ class Lexer(source: Source) {
               case None => err("Not a 64bit floating point literal.")
               case Some(n) => TokenKind.Float(n)
             }
-          case _ => TokenKind.Integer(slice().toInt)
+          case _ => slice().toLongOption match {
+            case None => err("Not a 64bit integer literal.")
+            case Some(n) => TokenKind.Integer(n)
+          }
         }
       }
       case _ =>

examples/pos/int_ufcs.check

@@ -0,0 +1,2 @@
+1234567890123
+1234567890123

examples/pos/int_ufcs.effekt

@@ -0,0 +1,5 @@
+def main() = {
+  1234567890123.println
+  println(1234567890123)
+}
+