passing compile-time bitwise tests (but not runtime :?)

stint/private/uint_shift.nim

@@ -40,7 +40,7 @@ func shrLarge*(r: var Limbs, a: Limbs, w, shift: SomeInteger) =
   when cpuEndian == littleEndian:
     for i in w ..< a.len-1:
       r[i-w] = (a[i] shr shift) or (a[i+1] shl (WordBitWidth - shift))
-    r[^w] = a[^1] shr shift
+    r[^(1+w)] = a[^1] shr shift
   else:
     for i in countdown(a.len-1, 1+w):
       r[i-w] = (a[i] shr shift) or (a[i-1] shl (WordBitWidth - k))

stint/uintops.nim

@@ -166,6 +166,7 @@ func `shr`*(a: Stuint, k: SomeInteger): Stuint {.inline.} =
   if k < WordBitWidth:
     result.limbs.shrSmall(a.limbs, k)
     return
+
   # w = k div WordBitWidth, shift = k mod WordBitWidth
   let w     = k shr static(log2trunc(uint32(WordBitWidth)))
   let shift = k and (WordBitWidth - 1)
@@ -181,6 +182,7 @@ func `shl`*(a: Stuint, k: SomeInteger): Stuint {.inline.} =
     result.limbs.shlSmall(a.limbs, k)
     result.clearExtraBits()
     return
+
   # w = k div WordBitWidth, shift = k mod WordBitWidth
   let w     = k shr static(log2trunc(uint32(WordBitWidth)))
   let shift = k and (WordBitWidth - 1)

tests/test_uint_bitwise.nim

@@ -337,12 +337,6 @@ suite "Testing unsigned int bitwise operations":
     check: cast[uint16](b) == z # Sanity check
     check: cast[uint16](b shl 8) == z shl 8
 
-    block: # Testing shl for nested UintImpl
-      let p2_64 = UintImpl[uint64](hi:1, lo:0)
-      let p = 1.stuint(128) shl 64
-
-      check: p == cast[StUint[128]](p2_64)
-
   test "Shift right - by less than half the size of the integer":
     check: cast[uint16](b) == z # Sanity check
     check: cast[uint16](b shr 2) == z shr 2