diff --git a/compiler/semfold.nim b/compiler/semfold.nim
index 501e66969a..1a3f40a47a 100644
--- a/compiler/semfold.nim
+++ b/compiler/semfold.nim
@@ -201,8 +201,8 @@ proc evalOp(m: TMagic, n, a, b, c: PNode; idgen: IdGenerator; g: ModuleGraph): P
         result = newIntNodeT(toInt128(toUInt64(getInt(a)) shl valueB), n, idgen, g)
     else: internalError(g.config, n.info, "constant folding for shl")
   of mShrI:
-    var a = cast[uint64](getInt(a))
-    let b = cast[uint64](getInt(b)) and cast[uint64](n.typ.size * 8 - 1)
+    var a = castToUInt64(getInt(a))
+    let b = castToUInt64(getInt(b)) and cast[uint64](n.typ.size * 8 - 1)
     # To support the ``-d:nimOldShiftRight`` flag, we need to mask the
     # signed integers to cut off the extended sign bit in the internal
     # representation.