fixes #13661 (#13664) [backport]

tests/misc/tunsignedconv.nim

@@ -1,3 +1,6 @@
+discard """
+  output: '''uint'''
+"""
 
 # Tests unsigned literals and implicit conversion between uints and ints
 # Passes if it compiles
@@ -43,3 +46,12 @@ block t4176:
   var yyy: uint8 = 0
   yyy = yyy - 127
   doAssert type(yyy) is uint8
+
+# bug #13661
+
+proc fun(): uint = cast[uint](-1)
+const x0 = fun()
+
+echo typeof(x0)
+
+discard $x0