added a .since annotation to hashIdentity

lib/pure/hashes.nim

@@ -44,6 +44,8 @@
 ## * `std/sha1 module <sha1.html>`_ for a sha1 encoder and decoder
 ## * `tables module <tables.html>`_ for hash tables
 
+include "system/inclrtl"
+
 type
   Hash* = int ## A hash value. Hash tables using these values should
                ## always have a size of a power of two and can use the ``and``
@@ -172,14 +174,14 @@ proc hash*[T: proc](x: T): Hash {.inline.} =
   else:
     result = hash(pointer(x))
 
-proc hashIdentity*[T: Ordinal](x: T): Hash {.inline.} =
+proc hashIdentity*[T: Ordinal](x: T): Hash {.inline, since: (1, 3).} =
   ## The identity hash.  I.e. ``hashIdentity(x) = x``.
   cast[Hash](ord(x))
 
 when defined(nimIntHash1):
   proc hash*[T: Ordinal](x: T): Hash {.inline.} =
     ## Efficient hashing of integers.
-    hashIdentity(x)
+    cast[Hash](ord(x))
 else:
   proc hash*[T: Ordinal](x: T): Hash {.inline.} =
     ## Efficient hashing of integers.