Add neg test

Author: odersky

tests/neg/genericNumbers.scala

@@ -0,0 +1,41 @@
+import scala.util.FromDigits
+
+object Test extends App {
+
+  val x: BigInt = 13232202002020202020202 // error
+  val z: BigDecimal = 132322020020.223 // error
+
+  case class Even(n: Int)
+
+  given FromDigits[Even] {
+    def fromDigits(digits: String): Even = {
+      val intValue = digits.toInt
+      if (intValue % 2 == 0) Even(intValue)
+      else throw FromDigits.MalformedNumber()
+    }
+  }
+
+  val e: Even = 1234 // error
+
+  try {
+    println(123: Even) // error
+  } catch {
+    case ex: FromDigits.MalformedNumber => println("malformed")
+  }
+
+  x match {
+    case 13_232_202_002_020_202_020_202 => () // error
+  }
+  (x: Any) match {
+    case 13232202002020202020202: BigInt => () // error
+  }
+  x match {
+    case 13232202002020202020202 => assert(false) // error
+    case -0xaabb12345ACF12345AC => () // error
+  }
+
+  (e: Any) match {
+    case 1234: Even => // error
+    case _: Even => // error
+  }
+}