mirror of https://go.googlesource.com/go
63 lines
1.5 KiB
Go
63 lines
1.5 KiB
Go
// run
|
|
|
|
// Copyright 2019 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// short-circuiting interface-to-concrete comparisons
|
|
// will not miss panics
|
|
|
|
package main
|
|
|
|
import (
|
|
"log"
|
|
"strings"
|
|
)
|
|
|
|
func main() {
|
|
var (
|
|
x interface{}
|
|
p *int
|
|
s []int
|
|
l *interface{}
|
|
r []*int
|
|
)
|
|
tests := []struct {
|
|
name string
|
|
errStr string
|
|
f func()
|
|
}{
|
|
{"switch case", "", func() {
|
|
switch x {
|
|
case x.(*int):
|
|
}
|
|
}},
|
|
{"interface conversion", "", func() { _ = x == x.(error) }},
|
|
{"type assertion", "", func() { _ = x == x.(*int) }},
|
|
{"out of bounds", "", func() { _ = x == s[1] }},
|
|
{"nil pointer dereference #1", "", func() { _ = x == *p }},
|
|
// TODO(mdempsky): Restore "nil pointer dereference" check. The Go
|
|
// spec doesn't mandate an order for panics (or even panic
|
|
// messages), but left-to-right is less confusing to users.
|
|
{"nil pointer dereference #2", "", func() { _ = *l == r[0] }},
|
|
{"nil pointer dereference #3", "", func() { _ = *l == any(r[0]) }},
|
|
}
|
|
|
|
for _, tc := range tests {
|
|
testFuncShouldPanic(tc.name, tc.errStr, tc.f)
|
|
}
|
|
}
|
|
|
|
func testFuncShouldPanic(name, want string, f func()) {
|
|
defer func() {
|
|
e := recover()
|
|
if e == nil {
|
|
log.Fatalf("%s: comparison did not panic\n", name)
|
|
}
|
|
if have := e.(error).Error(); !strings.Contains(have, want) {
|
|
log.Fatalf("%s: wrong panic message: have %q, want %q\n", name, have, want)
|
|
}
|
|
}()
|
|
f()
|
|
}
|