echo "For 32 bits signed integers with overflow check suppressed:"
{.push overflowChecks: off.}
var a: int32
a =  -(-2147483647i32 - 1'i32)
echo "  -(-2147483647-1) gives ", a           # -2147483648.
a =  2000000000i32 + 2000000000i32
echo "  2000000000 + 2000000000 gives ", a    # -294967296.
a =  -2147483647i32 - 2147483647i32
echo "  -2147483647 - 2147483647 gives ", a   # 2.
a = 46341i32 * 46341i32
echo "  46341 * 46341 gives ", a              # -2147479015.
a = (-2147483647i32 - 1i32) div -1i32
echo "  (-2147483647-1) / -1 gives ", a       # -2147483648.
{.pop.}
echo ""

echo "For 64 bits signed integers with overflow check suppressed:"
{.push overflowChecks: off.}
var b: int64
b = -(-9223372036854775807i64 - 1i64)
echo "  -(-9223372036854775807-1) gives ", b                    # -9223372036854775808.
b = 5000000000000000000i64 + 5000000000000000000i64
echo "  5000000000000000000 + 5000000000000000000 gives ", b    # -8446744073709551616.
b = -9223372036854775807i64 - 9223372036854775807i64
echo "  -9223372036854775807 - 9223372036854775807 gives ", b   # 2.
b = 3037000500i64 * 3037000500i64
echo "  3037000500 * 3037000500 gives ", b                      # -9223372036709301616.
b =  (-9223372036854775807i64 - 1i64) div -1i64
echo "  (-9223372036854775807-1) / -1 gives ", b                # -9223372036854775808.
{.pop.}
echo ""

echo "For 32 bits unsigned integers:"
var c: uint32
echo "  -4294967295 doesn’t compile."
c = 3000000000u32 + 3000000000u32
echo "  3000000000 + 3000000000 gives ", c    # 1705032704.
c = 2147483647u32 - 4294967295u32
echo "  2147483647 - 4294967295 gives ", c    # 2147483648.
c = 65537u32 * 65537u32
echo "  65537 * 65537 gives ", c              # 131073.
echo ""

echo "For 64 bits unsigned integers:"
var d: uint64
echo "  -18446744073709551615 doesn’t compile."
d = 10000000000000000000u64 + 10000000000000000000u64
echo "  10000000000000000000 + 10000000000000000000 gives ", d  # 1553255926290448384.
d = 9223372036854775807u64 - 18446744073709551615u64
echo "  9223372036854775807 - 18446744073709551615 gives ", d   # 9223372036854775808.
d = 4294967296u64 * 4294967296u64
echo "  4294967296 * 4294967296 gives ", d                      # 0.