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package main
// Tests of composite literals.
import "fmt"
// Map literals.
// TODO(adonovan): we can no longer print maps
// until the interpreter supports (reflect.Value).MapRange.
func _() {
type M map[int]int
m1 := []*M{{1: 1}, &M{2: 2}}
want := "map[1:1] map[2:2]"
if got := fmt.Sprint(*m1[0], *m1[1]); got != want {
panic(got)
}
m2 := []M{{1: 1}, M{2: 2}}
if got := fmt.Sprint(m2[0], m2[1]); got != want {
panic(got)
}
}
// Nonliteral keys in composite literal.
func init() {
const zero int = 1
var v = []int{1 + zero: 42}
if x := fmt.Sprint(v); x != "[0 0 42]" {
panic(x)
}
}
// Test for in-place initialization.
func init() {
// struct
type S struct {
a, b int
}
s := S{1, 2}
s = S{b: 3}
if s.a != 0 {
panic("s.a != 0")
}
if s.b != 3 {
panic("s.b != 3")
}
s = S{}
if s.a != 0 {
panic("s.a != 0")
}
if s.b != 0 {
panic("s.b != 0")
}
// array
type A [4]int
a := A{2, 4, 6, 8}
a = A{1: 6, 2: 4}
if a[0] != 0 {
panic("a[0] != 0")
}
if a[1] != 6 {
panic("a[1] != 6")
}
if a[2] != 4 {
panic("a[2] != 4")
}
if a[3] != 0 {
panic("a[3] != 0")
}
a = A{}
if a[0] != 0 {
panic("a[0] != 0")
}
if a[1] != 0 {
panic("a[1] != 0")
}
if a[2] != 0 {
panic("a[2] != 0")
}
if a[3] != 0 {
panic("a[3] != 0")
}
}
// Regression test for https://golang.org/issue/10127:
// composite literal clobbers destination before reading from it.
func init() {
// map
{
type M map[string]int
m := M{"x": 1, "y": 2}
m = M{"x": m["y"], "y": m["x"]}
if m["x"] != 2 || m["y"] != 1 {
panic(fmt.Sprint(m))
}
n := M{"x": 3}
m, n = M{"x": n["x"]}, M{"x": m["x"]} // parallel assignment
if got := fmt.Sprint(m["x"], n["x"]); got != "3 2" {
panic(got)
}
}
// struct
{
type T struct{ x, y, z int }
t := T{x: 1, y: 2, z: 3}
t = T{x: t.y, y: t.z, z: t.x} // all fields
if got := fmt.Sprint(t); got != "{2 3 1}" {
panic(got)
}
t = T{x: t.y, y: t.z + 3} // not all fields
if got := fmt.Sprint(t); got != "{3 4 0}" {
panic(got)
}
u := T{x: 5, y: 6, z: 7}
t, u = T{x: u.x}, T{x: t.x} // parallel assignment
if got := fmt.Sprint(t, u); got != "{5 0 0} {3 0 0}" {
panic(got)
}
}
// array
{
a := [3]int{0: 1, 1: 2, 2: 3}
a = [3]int{0: a[1], 1: a[2], 2: a[0]} // all elements
if got := fmt.Sprint(a); got != "[2 3 1]" {
panic(got)
}
a = [3]int{0: a[1], 1: a[2] + 3} // not all elements
if got := fmt.Sprint(a); got != "[3 4 0]" {
panic(got)
}
b := [3]int{0: 5, 1: 6, 2: 7}
a, b = [3]int{0: b[0]}, [3]int{0: a[0]} // parallel assignment
if got := fmt.Sprint(a, b); got != "[5 0 0] [3 0 0]" {
panic(got)
}
}
// slice
{
s := []int{0: 1, 1: 2, 2: 3}
s = []int{0: s[1], 1: s[2], 2: s[0]} // all elements
if got := fmt.Sprint(s); got != "[2 3 1]" {
panic(got)
}
s = []int{0: s[1], 1: s[2] + 3} // not all elements
if got := fmt.Sprint(s); got != "[3 4]" {
panic(got)
}
t := []int{0: 5, 1: 6, 2: 7}
s, t = []int{0: t[0]}, []int{0: s[0]} // parallel assignment
if got := fmt.Sprint(s, t); got != "[5] [3]" {
panic(got)
}
}
}
// Regression test for https://golang.org/issue/13341:
// within a map literal, if a key expression is a composite literal,
// Go 1.5 allows its type to be omitted. An & operation may be implied.
func init() {
type S struct{ x int }
// same as map[*S]bool{&S{x: 1}: true}
m := map[*S]bool{{x: 1}: true}
for s := range m {
if s.x != 1 {
panic(s) // wrong key
}
return
}
panic("map is empty")
}
func main() {
}
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