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Current Path: /opt/golang/1.19.4/test/interface

opt / golang / 1.19.4 / test / interface /

📁 ..
📄 assertinline.go(1.77 KB)
📄 bigdata.go(1.45 KB)
📄 convert.go(1.88 KB)
📄 convert1.go(393 B)
📄 convert2.go(393 B)
📄 embed.go(924 B)
📁 embed1.dir
📄 embed1.go(250 B)
📄 embed2.go(1.48 KB)
📁 embed3.dir
📄 embed3.go(187 B)
📄 explicit.go(1.96 KB)
📄 fail.go(544 B)
📄 fake.go(1.75 KB)
📄 noeq.go(641 B)
📄 pointer.go(758 B)
📁 private.dir
📄 private.go(285 B)
📄 receiver.go(1.26 KB)
📄 receiver1.go(790 B)
📄 recursive.go(374 B)
📁 recursive1.dir
📄 recursive1.go(267 B)
📄 returntype.go(670 B)
📄 struct.go(2.43 KB)

Editing: explicit.go

// errorcheck

// 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.

// Verify compiler messages about erroneous static interface conversions.
// Does not compile.

package main

type T struct {
	a int
}

var t *T

type X int

func (x *X) M() {}

type I interface {
	M()
}

var i I

type I2 interface {
	M()
	N()
}

var i2 I2

type E interface{}

var e E

func main() {
	e = t // ok
	t = e // ERROR "need explicit|need type assertion"

// neither of these can work,
	// because i has an extra method
	// that t does not, so i cannot contain a t.
	i = t // ERROR "incompatible|missing M method"
	t = i // ERROR "incompatible|assignment$"

i = i2 // ok
	i2 = i // ERROR "incompatible|missing N method"

i = I(i2)  // ok
	i2 = I2(i) // ERROR "invalid|missing N method|cannot convert"

e = E(t) // ok
	t = T(e) // ERROR "need explicit|need type assertion|incompatible|cannot convert"

// cannot type-assert non-interfaces
	f := 2.0
	_ = f.(int) // ERROR "non-interface type|only valid for interface types|not an interface"

}

type M interface {
	M()
}

var m M

var _ = m.(int) // ERROR "impossible type assertion"

type Int int

func (Int) M(float64) {}

var _ = m.(Int) // ERROR "impossible type assertion"

var _ = m.(X) // ERROR "pointer receiver"

var ii int
var jj Int

var m1 M = ii // ERROR "incompatible|missing"
var m2 M = jj // ERROR "incompatible|wrong type for M method"

var m3 = M(ii) // ERROR "invalid|missing|cannot convert"
var m4 = M(jj) // ERROR "invalid|wrong type for M method|cannot convert"

type B1 interface {
	_() // ERROR "methods must have a unique non-blank name"
}

type B2 interface {
	M()
	_() // ERROR "methods must have a unique non-blank name"
}

type T2 struct{}

func (t *T2) M() {}
func (t *T2) _() {}

// Already reported about the invalid blank interface method above;
// no need to report about not implementing it.
var b1 B1 = &T2{}
var b2 B2 = &T2{}

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Editing: explicit.go

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