Add a test.

tests/idris2/reg016/expected

@@ -0,0 +1,2 @@
+1/1: Building anyfail (anyfail.idr)
+anyfail.idr:21:1--22:1:showing (MkEvenMoreComplicated (MkMoreComplicated (MkComplicated (PtrAndSize addr len)))) SomethingVeryComplicatedIs is not a valid impossible case

tests/idris2/reg016/numbers.idr

@@ -0,0 +1,13 @@
+main : IO ()
+main = do
+  printLn $ 3
+  printLn $ 4.2
+  printLn $ "1.2"
+
+  printLn $ cast {to = Int} 4.8
+  printLn $ cast {to = Integer} 1.2
+  printLn $ cast {to = String} 2.7
+
+  printLn $ cast {to = Int} "1.2"
+  printLn $ cast {to = Integer} "2.7"
+  printLn $ cast {to = Double} "5.9"

tests/idris2/reg016/run

@@ -0,0 +1,3 @@
+$1 numbers.idr -x main
+
+rm -rf build