add testcase for overloadable_enums (nim-lang#18722)

* add testcase for overloadable_enums

* link

tests/enum/toverloadable_enums.nim

@@ -46,3 +46,32 @@ proc takeCallback(param: proc(p: int)) = discard
 takeCallback x
 
 echo ord v
+
+block: # https://github.com/nim-lang/RFCs/issues/8
+  type
+    Enum1 = enum
+      A, B, C
+    Enum2 = enum
+      A, Z
+
+  proc f(e: Enum1): int = ord(e)
+  proc g(e: Enum2): int = ord(e)
+
+  proc h(e: Enum1): int = ord(e)
+  proc h(e: Enum2): int = ord(e)
+
+  let fA = f(A) # Type of A is well defined
+  let gA = g(A) # Same as above
+
+  let hA1 = h(Enum1.A) # A requires disambiguation
+  let hA2 = h(Enum2.A) # Similarly
+  let hA3 = h(B)
+  let hA4 = h(B)
+  let x = ord(Enum1.A) # Also
+  doAssert fA == 0
+  doAssert gA == 0
+  doAssert hA1 == 0
+  doAssert hA2 == 0
+  doAssert x == 0
+  doAssert hA3 == 1
+  doAssert hA4 == 1