145 lines
2.2 KiB
Go
145 lines
2.2 KiB
Go
// Tests of bound method closures.
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package main
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import "fmt"
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func assert(b bool) {
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if !b {
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panic("oops")
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}
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}
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type I int
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func (i I) add(x int) int {
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return int(i) + x
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}
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func valueReceiver() {
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var three I = 3
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assert(three.add(5) == 8)
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var add3 func(int) int = three.add
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assert(add3(5) == 8)
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}
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type S struct{ x int }
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func (s *S) incr() {
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s.x++
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}
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func (s *S) get() int {
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return s.x
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}
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func pointerReceiver() {
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ps := new(S)
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incr := ps.incr
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get := ps.get
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assert(get() == 0)
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incr()
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incr()
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incr()
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assert(get() == 3)
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}
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func addressibleValuePointerReceiver() {
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var s S
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incr := s.incr
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get := s.get
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assert(get() == 0)
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incr()
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incr()
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incr()
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assert(get() == 3)
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}
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type S2 struct {
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S
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}
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func promotedReceiver() {
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var s2 S2
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incr := s2.incr
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get := s2.get
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assert(get() == 0)
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incr()
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incr()
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incr()
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assert(get() == 3)
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}
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func anonStruct() {
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var s struct{ S }
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incr := s.incr
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get := s.get
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assert(get() == 0)
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incr()
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incr()
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incr()
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assert(get() == 3)
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}
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func typeCheck() {
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var i interface{}
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i = (*S).incr
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_ = i.(func(*S)) // type assertion: receiver type prepended to params
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var s S
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i = s.incr
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_ = i.(func()) // type assertion: receiver type disappears
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}
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type errString string
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func (err errString) Error() string {
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return string(err)
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}
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// Regression test for a builder crash.
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func regress1(x error) func() string {
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return x.Error
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}
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// Regression test for b/7269:
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// taking the value of an interface method performs a nil check.
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func nilInterfaceMethodValue() {
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err := fmt.Errorf("ok")
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f := err.Error
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if got := f(); got != "ok" {
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panic(got)
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}
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err = nil
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if got := f(); got != "ok" {
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panic(got)
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}
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defer func() {
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r := fmt.Sprint(recover())
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// runtime panic string varies across toolchains
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if r != "runtime error: interface conversion: interface is nil, not error" &&
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r != "runtime error: invalid memory address or nil pointer dereference" {
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panic("want runtime panic from nil interface method value, got " + r)
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}
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}()
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f = err.Error // runtime panic: err is nil
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panic("unreachable")
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}
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func main() {
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valueReceiver()
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pointerReceiver()
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addressibleValuePointerReceiver()
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promotedReceiver()
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anonStruct()
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typeCheck()
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if e := regress1(errString("hi"))(); e != "hi" {
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panic(e)
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}
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nilInterfaceMethodValue()
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}
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