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go/test/cmp.go
Rémy Oudompheng e5f01aee04 cmd/gc: do not nop-convert equivalent but different interface types. 
The cached computed interface tables are indexed by the interface
types, not by the unnamed underlying interfaces

To preserve the invariants expected by interface comparison, an
itab generated for an interface type must not be used for a value
of a different interface type even if the representation is identical.

Fixes #7207.

LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/69210044
2014-02-27 08:07:50 +01:00

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// 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 equality and inequality operations.
package main
import (
"os"
"unsafe"
)
var global bool
func use(b bool) { global = b }
func stringptr(s string) uintptr { return *(*uintptr)(unsafe.Pointer(&s)) }
func isfalse(b bool) {
if b {
// stack will explain where
panic("wanted false, got true")
}
}
func istrue(b bool) {
if !b {
// stack will explain where
panic("wanted true, got false")
}
}
type T *int
type X int
func (X) x() {}
func main() {
var a []int
var b map[string]int
var c string = "hello"
var d string = "hel" // try to get different pointer
d = d + "lo"
// go.tools/ssa/interp can't handle unsafe.Pointer.
if os.Getenv("GOSSAINTERP") == "" {
if stringptr(c) == stringptr(d) {
panic("compiler too smart -- got same string")
}
}
var e = make(chan int)
var ia interface{} = a
var ib interface{} = b
var ic interface{} = c
var id interface{} = d
var ie interface{} = e
// these comparisons are okay because
// string compare is okay and the others
// are comparisons where the types differ.
isfalse(ia == ib)
isfalse(ia == ic)
isfalse(ia == id)
isfalse(ib == ic)
isfalse(ib == id)
istrue(ic == id)
istrue(ie == ie)
istrue(ia != ib)
istrue(ia != ic)
istrue(ia != id)
istrue(ib != ic)
istrue(ib != id)
isfalse(ic != id)
isfalse(ie != ie)
// these are not okay, because there is no comparison on slices or maps.
//isfalse(a == ib)
//isfalse(a == ic)
//isfalse(a == id)
//isfalse(b == ic)
//isfalse(b == id)
istrue(c == id)
istrue(e == ie)
//isfalse(ia == b)
isfalse(ia == c)
isfalse(ia == d)
isfalse(ib == c)
isfalse(ib == d)
istrue(ic == d)
istrue(ie == e)
//istrue(a != ib)
//istrue(a != ic)
//istrue(a != id)
//istrue(b != ic)
//istrue(b != id)
isfalse(c != id)
isfalse(e != ie)
//istrue(ia != b)
istrue(ia != c)
istrue(ia != d)
istrue(ib != c)
istrue(ib != d)
isfalse(ic != d)
isfalse(ie != e)
// 6g used to let this go through as true.
var g uint64 = 123
var h int64 = 123
var ig interface{} = g
var ih interface{} = h
isfalse(ig == ih)
istrue(ig != ih)
// map of interface should use == on interface values,
// not memory.
var m = make(map[interface{}]int)
m[ic] = 1
m[id] = 2
if m[c] != 2 {
println("m[c] = ", m[c])
panic("bad m[c]")
}
// interface comparisons (issue 7207)
{
type I1 interface {
x()
}
type I2 interface {
x()
}
a1 := I1(X(0))
b1 := I1(X(1))
a2 := I2(X(0))
b2 := I2(X(1))
a3 := I1(a2)
a4 := I2(a1)
var e interface{} = X(0)
a5 := e.(I1)
a6 := e.(I2)
isfalse(a1 == b1)
isfalse(a1 == b2)
isfalse(a2 == b1)
isfalse(a2 == b2)
istrue(a1 == a2)
istrue(a1 == a3)
istrue(a1 == a4)
istrue(a1 == a5)
istrue(a1 == a6)
istrue(a2 == a3)
istrue(a2 == a4)
istrue(a2 == a5)
istrue(a2 == a6)
istrue(a3 == a4)
istrue(a3 == a5)
istrue(a3 == a6)
istrue(a4 == a5)
istrue(a4 == a6)
istrue(a5 == a6)
}
// non-interface comparisons
{
c := make(chan int)
c1 := (<-chan int)(c)
c2 := (chan<- int)(c)
istrue(c == c1)
istrue(c == c2)
istrue(c1 == c)
istrue(c2 == c)
isfalse(c != c1)
isfalse(c != c2)
isfalse(c1 != c)
isfalse(c2 != c)
d := make(chan int)
isfalse(c == d)
isfalse(d == c)
isfalse(d == c1)
isfalse(d == c2)
isfalse(c1 == d)
isfalse(c2 == d)
istrue(c != d)
istrue(d != c)
istrue(d != c1)
istrue(d != c2)
istrue(c1 != d)
istrue(c2 != d)
}
// named types vs not
{
var x = new(int)
var y T
var z T = x
isfalse(x == y)
istrue(x == z)
isfalse(y == z)
isfalse(y == x)
istrue(z == x)
isfalse(z == y)
istrue(x != y)
isfalse(x != z)
istrue(y != z)
istrue(y != x)
isfalse(z != x)
istrue(z != y)
}
// structs
{
var x = struct {
x int
y string
}{1, "hi"}
var y = struct {
x int
y string
}{2, "bye"}
var z = struct {
x int
y string
}{1, "hi"}
isfalse(x == y)
isfalse(y == x)
isfalse(y == z)
isfalse(z == y)
istrue(x == z)
istrue(z == x)
istrue(x != y)
istrue(y != x)
istrue(y != z)
istrue(z != y)
isfalse(x != z)
isfalse(z != x)
var m = make(map[struct {
x int
y string
}]int)
m[x] = 10
m[y] = 20
m[z] = 30
istrue(m[x] == 30)
istrue(m[y] == 20)
istrue(m[z] == 30)
istrue(m[x] != 10)
isfalse(m[x] != 30)
isfalse(m[y] != 20)
isfalse(m[z] != 30)
isfalse(m[x] == 10)
var m1 = make(map[struct {
x int
y string
}]struct {
x int
y string
})
m1[x] = x
m1[y] = y
m1[z] = z
istrue(m1[x] == z)
istrue(m1[y] == y)
istrue(m1[z] == z)
istrue(m1[x] == x)
isfalse(m1[x] != z)
isfalse(m1[y] != y)
isfalse(m1[z] != z)
isfalse(m1[x] != x)
var ix, iy, iz interface{} = x, y, z
isfalse(ix == iy)
isfalse(iy == ix)
isfalse(iy == iz)
isfalse(iz == iy)
istrue(ix == iz)
istrue(iz == ix)
isfalse(x == iy)
isfalse(y == ix)
isfalse(y == iz)
isfalse(z == iy)
istrue(x == iz)
istrue(z == ix)
isfalse(ix == y)
isfalse(iy == x)
isfalse(iy == z)
isfalse(iz == y)
istrue(ix == z)
istrue(iz == x)
istrue(ix != iy)
istrue(iy != ix)
istrue(iy != iz)
istrue(iz != iy)
isfalse(ix != iz)
isfalse(iz != ix)
istrue(x != iy)
istrue(y != ix)
istrue(y != iz)
istrue(z != iy)
isfalse(x != iz)
isfalse(z != ix)
istrue(ix != y)
istrue(iy != x)
istrue(iy != z)
istrue(iz != y)
isfalse(ix != z)
isfalse(iz != x)
}
// structs with _ fields
{
var x = struct {
x int
_ string
y float64
_ float64
z int
}{
x: 1, y: 2, z: 3,
}
var ix interface{} = x
istrue(x == x)
istrue(x == ix)
istrue(ix == x)
istrue(ix == ix)
}
// arrays
{
var x = [2]string{"1", "hi"}
var y = [2]string{"2", "bye"}
var z = [2]string{"1", "hi"}
isfalse(x == y)
isfalse(y == x)
isfalse(y == z)
isfalse(z == y)
istrue(x == z)
istrue(z == x)
istrue(x != y)
istrue(y != x)
istrue(y != z)
istrue(z != y)
isfalse(x != z)
isfalse(z != x)
var m = make(map[[2]string]int)
m[x] = 10
m[y] = 20
m[z] = 30
istrue(m[x] == 30)
istrue(m[y] == 20)
istrue(m[z] == 30)
isfalse(m[x] != 30)
isfalse(m[y] != 20)
isfalse(m[z] != 30)
var ix, iy, iz interface{} = x, y, z
isfalse(ix == iy)
isfalse(iy == ix)
isfalse(iy == iz)
isfalse(iz == iy)
istrue(ix == iz)
istrue(iz == ix)
isfalse(x == iy)
isfalse(y == ix)
isfalse(y == iz)
isfalse(z == iy)
istrue(x == iz)
istrue(z == ix)
isfalse(ix == y)
isfalse(iy == x)
isfalse(iy == z)
isfalse(iz == y)
istrue(ix == z)
istrue(iz == x)
istrue(ix != iy)
istrue(iy != ix)
istrue(iy != iz)
istrue(iz != iy)
isfalse(ix != iz)
isfalse(iz != ix)
istrue(x != iy)
istrue(y != ix)
istrue(y != iz)
istrue(z != iy)
isfalse(x != iz)
isfalse(z != ix)
istrue(ix != y)
istrue(iy != x)
istrue(iy != z)
istrue(iz != y)
isfalse(ix != z)
isfalse(iz != x)
}
// named booleans
{
type mybool bool
var b mybool
type T struct{ data [20]byte }
var x, y T
b = x == y
istrue(x == y)
istrue(bool(b))
m := make(map[string][10]interface{})
b = m["x"] == m["y"]
istrue(m["x"] == m["y"])
istrue(bool(b))
}
shouldPanic(p1)
shouldPanic(p2)
shouldPanic(p3)
shouldPanic(p4)
}
func p1() {
var a []int
var ia interface{} = a
use(ia == ia)
}
func p2() {
var b []int
var ib interface{} = b
use(ib == ib)
}
func p3() {
var a []int
var ia interface{} = a
var m = make(map[interface{}]int)
m[ia] = 1
}
func p4() {
var b []int
var ib interface{} = b
var m = make(map[interface{}]int)
m[ib] = 1
}
func shouldPanic(f func()) {
defer func() {
if recover() == nil {
panic("function should panic")
}
}()
f()
}
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