fixes #11764, faster hashing of (u)int (#12407)

Author: narimiran

lib/pure/collections/sets.nim

@@ -1019,9 +1019,9 @@ when isMainModule and not defined(release):
       # --> {1, 3, 5}
 
     block toSeqAndString:
-      var a = toHashSet([2, 4, 5])
+      var a = toHashSet([2, 7, 5])
       var b = initHashSet[int]()
-      for x in [2, 4, 5]: b.incl(x)
+      for x in [2, 7, 5]: b.incl(x)
       assert($a == $b)
       #echo a
       #echo toHashSet(["no", "esc'aping", "is \" provided"])

lib/pure/hashes.nim

@@ -112,29 +112,32 @@ proc hash*[T: proc](x: T): Hash {.inline.} =
   else:
     result = hash(pointer(x))
 
+const
+  prime = uint(11)
+
 proc hash*(x: int): Hash {.inline.} =
   ## Efficient hashing of integers.
-  result = x
+  result = cast[Hash](cast[uint](x) * prime)
 
 proc hash*(x: int64): Hash {.inline.} =
   ## Efficient hashing of `int64` integers.
-  result = cast[int](x)
+  result = cast[Hash](cast[uint](x) * prime)
 
 proc hash*(x: uint): Hash {.inline.} =
   ## Efficient hashing of unsigned integers.
-  result = cast[int](x)
+  result = cast[Hash](x * prime)
 
 proc hash*(x: uint64): Hash {.inline.} =
   ## Efficient hashing of `uint64` integers.
-  result = cast[int](x)
+  result = cast[Hash](cast[uint](x) * prime)
 
 proc hash*(x: char): Hash {.inline.} =
   ## Efficient hashing of characters.
-  result = ord(x)
+  result = cast[Hash](cast[uint](ord(x)) * prime)
 
 proc hash*[T: Ordinal](x: T): Hash {.inline.} =
   ## Efficient hashing of other ordinal types (e.g. enums).
-  result = ord(x)
+  result = cast[Hash](cast[uint](ord(x)) * prime)
 
 proc hash*(x: float): Hash {.inline.} =
   ## Efficient hashing of floats.

tests/collections/ttables.nim

@@ -233,7 +233,7 @@ block tablesref:
       for y in 0..1:
         assert t[(x,y)] == $x & $y
     assert($t ==
-      "{(x: 0, y: 1): \"01\", (x: 0, y: 0): \"00\", (x: 1, y: 0): \"10\", (x: 1, y: 1): \"11\"}")
+      "{(x: 1, y: 1): \"11\", (x: 0, y: 0): \"00\", (x: 0, y: 1): \"01\", (x: 1, y: 0): \"10\"}")
 
   block tableTest2:
     var t = newTable[string, float]()
@@ -340,7 +340,7 @@ block tablesref:
   block anonZipTest:
     let keys = @['a','b','c']
     let values = @[1, 2, 3]
-    doAssert "{'a': 1, 'b': 2, 'c': 3}" == $ toTable zip(keys, values)
+    doAssert "{'c': 3, 'a': 1, 'b': 2}" == $ toTable zip(keys, values)
 
   block clearTableTest:
     var t = newTable[string, float]()

tests/collections/ttablesthreads.nim

@@ -48,7 +48,7 @@ block tableTest1:
     for y in 0..1:
       assert t[(x,y)] == $x & $y
   assert($t ==
-    "{(x: 0, y: 1): \"01\", (x: 0, y: 0): \"00\", (x: 1, y: 0): \"10\", (x: 1, y: 1): \"11\"}")
+    "{(x: 1, y: 1): \"11\", (x: 0, y: 0): \"00\", (x: 0, y: 1): \"01\", (x: 1, y: 0): \"10\"}")
 
 block tableTest2:
   var t = initTable[string, float]()