// run // Copyright 2009 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. // Test simple methods of various types, with pointer and // value receivers. package main type S string type S1 string type I int type I1 int type T struct { x int } type T1 T func (s S) val() int { return 1 } func (s *S1) val() int { return 2 } func (i I) val() int { return 3 } func (i *I1) val() int { return 4 } func (t T) val() int { return 7 } func (t *T1) val() int { return 8 } type Val interface { val() int } func val(v Val) int { return v.val() } func main() { var s S var ps *S1 var i I var pi *I1 var pt *T1 var t T var v Val if s.val() != 1 { println("s.val:", s.val()) panic("fail") } if S.val(s) != 1 { println("S.val(s):", S.val(s)) panic("fail") } if (*S).val(&s) != 1 { println("(*S).val(s):", (*S).val(&s)) panic("fail") } if ps.val() != 2 { println("ps.val:", ps.val()) panic("fail") } if (*S1).val(ps) != 2 { println("(*S1).val(ps):", (*S1).val(ps)) panic("fail") } if i.val() != 3 { println("i.val:", i.val()) panic("fail") } if I.val(i) != 3 { println("I.val(i):", I.val(i)) panic("fail") } if (*I).val(&i) != 3 { println("(*I).val(&i):", (*I).val(&i)) panic("fail") } if pi.val() != 4 { println("pi.val:", pi.val()) panic("fail") } if (*I1).val(pi) != 4 { println("(*I1).val(pi):", (*I1).val(pi)) panic("fail") } if t.val() != 7 { println("t.val:", t.val()) panic("fail") } if pt.val() != 8 { println("pt.val:", pt.val()) panic("fail") } if (*T1).val(pt) != 8 { println("(*T1).val(pt):", (*T1).val(pt)) panic("fail") } if val(s) != 1 { println("val(s):", val(s)) panic("fail") } if val(ps) != 2 { println("val(ps):", val(ps)) panic("fail") } if val(i) != 3 { println("val(i):", val(i)) panic("fail") } if val(pi) != 4 { println("val(pi):", val(pi)) panic("fail") } if val(t) != 7 { println("val(t):", val(t)) panic("fail") } if val(pt) != 8 { println("val(pt):", val(pt)) panic("fail") } if Val.val(i) != 3 { println("Val.val(i):", Val.val(i)) panic("fail") } v = i if Val.val(v) != 3 { println("Val.val(v):", Val.val(v)) panic("fail") } var zs struct{ S } var zps struct{ *S1 } var zi struct{ I } var zpi struct{ *I1 } var zpt struct{ *T1 } var zt struct{ T } var zv struct{ Val } if zs.val() != 1 { println("zs.val:", zs.val()) panic("fail") } if zps.val() != 2 { println("zps.val:", zps.val()) panic("fail") } if zi.val() != 3 { println("zi.val:", zi.val()) panic("fail") } if zpi.val() != 4 { println("zpi.val:", zpi.val()) panic("fail") } if zt.val() != 7 { println("zt.val:", zt.val()) panic("fail") } if zpt.val() != 8 { println("zpt.val:", zpt.val()) panic("fail") } if val(zs) != 1 { println("val(zs):", val(zs)) panic("fail") } if val(zps) != 2 { println("val(zps):", val(zps)) panic("fail") } if val(zi) != 3 { println("val(zi):", val(zi)) panic("fail") } if val(zpi) != 4 { println("val(zpi):", val(zpi)) panic("fail") } if val(zt) != 7 { println("val(zt):", val(zt)) panic("fail") } if val(zpt) != 8 { println("val(zpt):", val(zpt)) panic("fail") } zv.Val = zi if zv.val() != 3 { println("zv.val():", zv.val()) panic("fail") } if (&zs).val() != 1 { println("(&zs).val:", (&zs).val()) panic("fail") } if (&zps).val() != 2 { println("(&zps).val:", (&zps).val()) panic("fail") } if (&zi).val() != 3 { println("(&zi).val:", (&zi).val()) panic("fail") } if (&zpi).val() != 4 { println("(&zpi).val:", (&zpi).val()) panic("fail") } if (&zt).val() != 7 { println("(&zt).val:", (&zt).val()) panic("fail") } if (&zpt).val() != 8 { println("(&zpt).val:", (&zpt).val()) panic("fail") } if val(&zs) != 1 { println("val(&zs):", val(&zs)) panic("fail") } if val(&zps) != 2 { println("val(&zps):", val(&zps)) panic("fail") } if val(&zi) != 3 { println("val(&zi):", val(&zi)) panic("fail") } if val(&zpi) != 4 { println("val(&zpi):", val(&zpi)) panic("fail") } if val(&zt) != 7 { println("val(&zt):", val(&zt)) panic("fail") } if val(&zpt) != 8 { println("val(&zpt):", val(&zpt)) panic("fail") } zv.Val = &zi if zv.val() != 3 { println("zv.val():", zv.val()) panic("fail") } promotion() } type A struct{ B } type B struct { C *D } type C int func (C) f() {} // value receiver, direct field of A func (*C) g() {} // pointer receiver type D int func (D) h() {} // value receiver, indirect field of A func (*D) i() {} // pointer receiver func expectPanic() { if r := recover(); r == nil { panic("expected nil dereference") } } func promotion() { var a A // Addressable value receiver. a.f() a.g() func() { defer expectPanic() a.h() // dynamic error: nil dereference in a.B.D->f() }() a.i() // Non-addressable value receiver. A(a).f() // A(a).g() // static error: cannot call pointer method on A literal.B.C func() { defer expectPanic() A(a).h() // dynamic error: nil dereference in A().B.D->f() }() A(a).i() // Pointer receiver. (&a).f() (&a).g() func() { defer expectPanic() (&a).h() // dynamic error: nil deref: nil dereference in (&a).B.D->f() }() (&a).i() c := new(C) c.f() // makes a copy c.g() }