// A shift's result type follows the left operand, not the count. Where the
// left operand is an untyped constant too wide for the count's type, adopting
// the count's type truncated it: `0x20000000000000 >> uint32(k)` computed 0
// where Go computes 2^49. math.expm1 relies on this expression, so the whole
// function returned 0 for the affected branch.
package main

func shifted(k uint32) (r uint64) {
	return uint64(0x20000000000000 >> k)
}

func combined(k uint32) (r uint64) {
	return uint64(0x3ff0000000000000 - (0x20000000000000 >> k))
}

func main() {
	if shifted(0) != 9007199254740992 {
		panic("shift truncated the left operand")
	}
	if shifted(10) != 9007199254740992>>10 {
		panic("shift by 10 truncated the left operand")
	}
	if combined(0) != 4598175219545276416 {
		panic("subtraction over the shift was wrong")
	}
	if combined(20) != 4607182410210082816 {
		panic("subtraction over the shift was wrong at 20")
	}
	println(combined(0))
}