1// run
2
3// Copyright 2020 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7// Issue #43480: ICE on large uint64 constants in switch cases.
8
9package main
10
11func isPow10(x uint64) bool {
12	switch x {
13	case 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
14		1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19:
15		return true
16	}
17	return false
18}
19
20func main() {
21	var x uint64 = 1
22
23	for {
24		if !isPow10(x) || isPow10(x-1) || isPow10(x+1) {
25			panic(x)
26		}
27		next := x * 10
28		if next/10 != x {
29			break // overflow
30		}
31		x = next
32	}
33}
34