in prepration for the upcoming different integer inference rules

lib/core/macros.nim

@@ -669,7 +669,7 @@ proc astGenRepr*(n: NimNode): string {.compileTime, benign.} =
         t = x
       result = newString(len)
       for j in countdown(len-1, 0):
-        result[j] = HexChars[t and 0xF]
+        result[j] = HexChars[int(t and 0xF)]
         t = t shr 4
         # handle negative overflow
         if t == 0 and x < 0: t = -1

lib/pure/strutils.nim

@@ -888,7 +888,7 @@ proc toHex*(x: BiggestInt, len: Positive): string {.noSideEffect,
     n = x
   result = newString(len)
   for j in countdown(len-1, 0):
-    result[j] = HexChars[n and 0xF]
+    result[j] = HexChars[int(n and 0xF)]
     n = n shr 4
     # handle negative overflow
     if n == 0 and x < 0: n = -1