package builtins
type Bmc interface {
- type map[rune]string, chan int
+ ~map[rune]string | ~chan int
}
type Bms interface {
- type map[string]int, []int
+ ~map[string]int | ~[]int
}
type Bcs interface {
- type chan bool, []float64
+ ~chan bool | ~[]float64
}
type Bss interface {
- type []int, []string
+ ~[]int | ~[]string
}
func _[T any] () {
// type with a type list constraint, all of the type argument's types in its
// bound, but at least one (!), must be in the type list of the bound of the
// corresponding parameterized type's type parameter.
-type T1[P interface{type uint}] struct{}
+type T1[P interface{~uint}] struct{}
func _[P any]() {
_ = T1[P /* ERROR P has no type constraints */ ]{}
// This is the original (simplified) program causing the same issue.
type Unsigned interface {
- type uint
+ ~uint
}
type T2[U Unsigned] struct {
// predicate disjunction in the implementation was wrong because if a type list
// contains both an integer and a floating-point type, the type parameter is
// neither an integer or a floating-point number.
-func convert[T1, T2 interface{type int, uint, float32}](v T1) T2 {
+func convert[T1, T2 interface{~int | ~uint | ~float32}](v T1) T2 {
return T2(v)
}
// both numeric, or both strings. The implementation had the same problem
// with this check as the conversion issue above (issue #39623).
-func issue39623[T interface{type int, string}](x, y T) T {
+func issue39623[T interface{~int | ~string}](x, y T) T {
return x + y
}
// Simplified, from https://go2goplay.golang.org/p/efS6x6s-9NI:
-func Sum[T interface{type int, string}](s []T) (sum T) {
+func Sum[T interface{~int | ~string}](s []T) (sum T) {
for _, v := range s {
sum += v
}
// Assignability of an unnamed pointer type to a type parameter that
// has a matching underlying type.
-func _[T interface{}, PT interface{type *T}] (x T) PT {
+func _[T interface{}, PT interface{~*T}] (x T) PT {
return &x
}
// Indexing of generic types containing type parameters in their type list:
-func at[T interface{ type []E }, E interface{}](x T, i int) E {
+func at[T interface{ ~[]E }, E interface{}](x T, i int) E {
return x[i]
}
// A generic type inside a function acts like a named type. Its underlying
// type is itself, its "operational type" is defined by the type list in
// the tybe bound, if any.
-func _[T interface{type int}](x T) {
+func _[T interface{~int}](x T) {
type myint int
var _ int = int(x)
var _ T = 42
// Indexing a generic type with an array type bound checks length.
// (Example by mdempsky@.)
-func _[T interface { type [10]int }](x T) {
+func _[T interface { ~[10]int }](x T) {
_ = x[9] // ok
_ = x[20 /* ERROR out of bounds */ ]
}
// Pointer indirection of a generic type.
-func _[T interface{ type *int }](p T) int {
+func _[T interface{ ~*int }](p T) int {
return *p
}
// Channel sends and receives on generic types.
-func _[T interface{ type chan int }](ch T) int {
+func _[T interface{ ~chan int }](ch T) int {
ch <- 0
return <- ch
}
// Calling of a generic variable.
-func _[T interface{ type func() }](f T) {
+func _[T interface{ ~func() }](f T) {
f()
go f()
}
// type parameter that was substituted with a defined type.
// Test case from an (originally) failing example.
-type sliceOf[E any] interface{ type []E }
+type sliceOf[E any] interface{ ~[]E }
func append[T interface{}, S sliceOf[T], T2 interface{ T }](s S, t ...T2) S
// Numeric is type bound that matches any numeric type.
// It would likely be in a constraints package in the standard library.
type Numeric interface {
- type int, int8, int16, int32, int64,
- uint, uint8, uint16, uint32, uint64, uintptr,
- float32, float64,
- complex64, complex128
+ ~int | ~int8 | ~int16 | ~int32 | ~int64 |
+ ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
+ ~float32 | ~float64 |
+ ~complex64 | ~complex128
}
func DotProduct[T Numeric](s1, s2 []T) T {
// OrderedNumeric is a type bound that matches numeric types that support the < operator.
type OrderedNumeric interface {
- type int, int8, int16, int32, int64,
- uint, uint8, uint16, uint32, uint64, uintptr,
- float32, float64
+ ~int | ~int8 | ~int16 | ~int32 | ~int64 |
+ ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
+ ~float32 | ~float64
}
// Complex is a type bound that matches the two complex types, which do not have a < operator.
type Complex interface {
- type complex64, complex128
+ ~complex64 | ~complex128
}
// OrderedAbs is a helper type that defines an Abs method for
// TODO(rFindley) the below partially applied function types should probably
// not be permitted (spec question).
-func f0[A any, B interface{type C}, C interface{type D}, D interface{type A}](A, B, C, D)
+func f0[A any, B interface{~C}, C interface{~D}, D interface{~A}](A, B, C, D)
func _() {
f := f0[string]
f("a", "b", "c", "d")
f0("a", "b", "c", "d")
}
-func f1[A any, B interface{type A}](A, B)
+func f1[A any, B interface{~A}](A, B)
func _() {
f := f1[int]
f(int(0), int(0))
f1(int(0), int(0))
}
-func f2[A any, B interface{type []A}](A, B)
+func f2[A any, B interface{~[]A}](A, B)
func _() {
f := f2[byte]
f(byte(0), []byte{})
f2(byte(0), []byte{})
}
-func f3[A any, B interface{type C}, C interface{type *A}](A, B, C)
+func f3[A any, B interface{~C}, C interface{~*A}](A, B, C)
func _() {
f := f3[int]
var x int
f3(x, &x, &x)
}
-func f4[A any, B interface{type []C}, C interface{type *A}](A, B, C)
+func f4[A any, B interface{~[]C}, C interface{~*A}](A, B, C)
func _() {
f := f4[int]
var x int
f4(x, []*int{}, &x)
}
-func f5[A interface{type struct{b B; c C}}, B any, C interface{type *B}](x B) A
+func f5[A interface{~struct{b B; c C}}, B any, C interface{~*B}](x B) A
func _() {
x := f5(1.2)
var _ float64 = x.b
var _ float64 = *x.c
}
-func f6[A any, B interface{type struct{f []A}}](B) A
+func f6[A any, B interface{~struct{f []A}}](B) A
func _() {
x := f6(struct{f []string}{})
var _ string = x
// TODO(gri) Need to flag invalid recursive constraints. At the
// moment these cause infinite recursions and stack overflow.
-// func f7[A interface{type B}, B interface{type A}]()
+// func f7[A interface{type B}, B interface{~A}]()
// More realistic examples
-func Double[S interface{ type []E }, E interface{ type int, int8, int16, int32, int64 }](s S) S {
+func Double[S interface{ ~[]E }, E interface{ ~int | ~int8 | ~int16 | ~int32 | ~int64 }](s S) S {
r := make(S, len(s))
for i, v := range s {
r[i] = v + v
type Setter[B any] interface {
Set(string)
- type *B
+ ~*B
}
func FromStrings[T interface{}, PT Setter[T]](s []string) []T {
p.pm()
}
-// An interface can (explicitly) declare at most one type list.
+// It is ok to have multiple embedded unions.
type _ interface {
m0()
- type int, string, bool
- type /* ERROR multiple type lists */ float32, float64
+ ~int | ~string | ~bool
+ ~float32 | ~float64
m1()
m2()
- type /* ERROR multiple type lists */ complex64, complex128
- type /* ERROR multiple type lists */ rune
+ ~complex64 | ~complex128
+ ~rune
}
// Interface type lists may contain each type at most once.
// for them to be all in a single list, and we report the error
// as well.)
type _ interface {
- type int, int /* ERROR duplicate term int */
- type /* ERROR multiple type lists */ int /* ERROR duplicate term int */
+ ~int|~ /* ERROR duplicate term int */ int
+ ~int|int /* ERROR duplicate term int */
+ int|int /* ERROR duplicate term int */
}
type _ interface {
- type struct{f int}, struct{g int}, struct /* ERROR duplicate term */ {f int}
+ ~struct{f int} | ~struct{g int} | ~ /* ERROR duplicate term */ struct{f int}
}
// Interface type lists can contain any type, incl. *Named types.
// Verify that we use the underlying type to compute the operational type.
type MyInt int
-func add1[T interface{type MyInt}](x T) T {
+func add1[T interface{~MyInt}](x T) T {
return x + 1
}
type MyString string
-func double[T interface{type MyInt, MyString}](x T) T {
+func double[T interface{~MyInt | ~MyString}](x T) T {
return x + x
}
// type lists.
type E0 interface {
- type int, bool, string
+ ~int | ~bool | ~string
}
type E1 interface {
- type int, float64, string
+ ~int | ~float64 | ~string
}
type E2 interface {
- type float64
+ ~float64
}
type I0 interface {
type I0_ interface {
E0
- type int
+ ~int
}
func f0_[T I0_]()
type F[A, B any] func(A, B) (B, A)
-func min[T interface{ type int }](x, y T) T {
+func min[T interface{ ~int }](x, y T) T {
if x < y {
return x
}
return y
}
-func _[T interface{type int, float32}](x, y T) bool { return x < y }
+func _[T interface{~int | ~float32}](x, y T) bool { return x < y }
func _[T any](x, y T) bool { return x /* ERROR cannot compare */ < y }
-func _[T interface{type int, float32, bool}](x, y T) bool { return x /* ERROR cannot compare */ < y }
+func _[T interface{~int | ~float32 | ~bool}](x, y T) bool { return x /* ERROR cannot compare */ < y }
func _[T C1[T]](x, y T) bool { return x /* ERROR cannot compare */ < y }
func _[T C2[T]](x, y T) bool { return x < y }
type C1[T any] interface{}
-type C2[T any] interface{ type int, float32 }
+type C2[T any] interface{ ~int | ~float32 }
func new[T any]() *T {
var x T
// indexing
func _[T any] (x T, i int) { _ = x /* ERROR "cannot index" */ [i] }
-func _[T interface{ type int }] (x T, i int) { _ = x /* ERROR "cannot index" */ [i] }
-func _[T interface{ type string }] (x T, i int) { _ = x[i] }
-func _[T interface{ type []int }] (x T, i int) { _ = x[i] }
-func _[T interface{ type [10]int, *[20]int, map[int]int }] (x T, i int) { _ = x[i] }
-func _[T interface{ type string, []byte }] (x T, i int) { _ = x[i] }
-func _[T interface{ type []int, [1]rune }] (x T, i int) { _ = x /* ERROR "cannot index" */ [i] }
-func _[T interface{ type string, []rune }] (x T, i int) { _ = x /* ERROR "cannot index" */ [i] }
+func _[T interface{ ~int }] (x T, i int) { _ = x /* ERROR "cannot index" */ [i] }
+func _[T interface{ ~string }] (x T, i int) { _ = x[i] }
+func _[T interface{ ~[]int }] (x T, i int) { _ = x[i] }
+func _[T interface{ ~[10]int | ~*[20]int | ~map[int]int }] (x T, i int) { _ = x[i] }
+func _[T interface{ ~string | ~[]byte }] (x T, i int) { _ = x[i] }
+func _[T interface{ ~[]int | ~[1]rune }] (x T, i int) { _ = x /* ERROR "cannot index" */ [i] }
+func _[T interface{ ~string | ~[]rune }] (x T, i int) { _ = x /* ERROR "cannot index" */ [i] }
// indexing with various combinations of map types in type lists (see issue #42616)
-func _[T interface{ type []E, map[int]E }, E any](x T, i int) { _ = x[i] }
-func _[T interface{ type []E }, E any](x T, i int) { _ = &x[i] }
-func _[T interface{ type map[int]E }, E any](x T, i int) { _, _ = x[i] } // comma-ok permitted
-func _[T interface{ type []E, map[int]E }, E any](x T, i int) { _ = &x /* ERROR cannot take address */ [i] }
-func _[T interface{ type []E, map[int]E, map[uint]E }, E any](x T, i int) { _ = x /* ERROR cannot index */ [i] } // different map element types
-func _[T interface{ type []E, map[string]E }, E any](x T, i int) { _ = x[i /* ERROR cannot use i */ ] }
+func _[T interface{ ~[]E | ~map[int]E }, E any](x T, i int) { _ = x[i] }
+func _[T interface{ ~[]E }, E any](x T, i int) { _ = &x[i] }
+func _[T interface{ ~map[int]E }, E any](x T, i int) { _, _ = x[i] } // comma-ok permitted
+func _[T interface{ ~[]E | ~map[int]E }, E any](x T, i int) { _ = &x /* ERROR cannot take address */ [i] }
+func _[T interface{ ~[]E | ~map[int]E | ~map[uint]E }, E any](x T, i int) { _ = x /* ERROR cannot index */ [i] } // different map element types
+func _[T interface{ ~[]E | ~map[string]E }, E any](x T, i int) { _ = x[i /* ERROR cannot use i */ ] }
// slicing
// TODO(gri) implement this
-func _[T interface{ type string }] (x T, i, j, k int) { _ = x /* ERROR invalid operation */ [i:j:k] }
+func _[T interface{ ~string }] (x T, i, j, k int) { _ = x /* ERROR invalid operation */ [i:j:k] }
// len/cap built-ins
func _[T any](x T) { _ = len(x /* ERROR invalid argument */ ) }
-func _[T interface{ type int }](x T) { _ = len(x /* ERROR invalid argument */ ) }
-func _[T interface{ type string, []byte, int }](x T) { _ = len(x /* ERROR invalid argument */ ) }
-func _[T interface{ type string }](x T) { _ = len(x) }
-func _[T interface{ type [10]int }](x T) { _ = len(x) }
-func _[T interface{ type []byte }](x T) { _ = len(x) }
-func _[T interface{ type map[int]int }](x T) { _ = len(x) }
-func _[T interface{ type chan int }](x T) { _ = len(x) }
-func _[T interface{ type string, []byte, chan int }](x T) { _ = len(x) }
+func _[T interface{ ~int }](x T) { _ = len(x /* ERROR invalid argument */ ) }
+func _[T interface{ ~string | ~[]byte | ~int }](x T) { _ = len(x /* ERROR invalid argument */ ) }
+func _[T interface{ ~string }](x T) { _ = len(x) }
+func _[T interface{ ~[10]int }](x T) { _ = len(x) }
+func _[T interface{ ~[]byte }](x T) { _ = len(x) }
+func _[T interface{ ~map[int]int }](x T) { _ = len(x) }
+func _[T interface{ ~chan int }](x T) { _ = len(x) }
+func _[T interface{ ~string | ~[]byte | ~chan int }](x T) { _ = len(x) }
func _[T any](x T) { _ = cap(x /* ERROR invalid argument */ ) }
-func _[T interface{ type int }](x T) { _ = cap(x /* ERROR invalid argument */ ) }
-func _[T interface{ type string, []byte, int }](x T) { _ = cap(x /* ERROR invalid argument */ ) }
-func _[T interface{ type string }](x T) { _ = cap(x /* ERROR invalid argument */ ) }
-func _[T interface{ type [10]int }](x T) { _ = cap(x) }
-func _[T interface{ type []byte }](x T) { _ = cap(x) }
-func _[T interface{ type map[int]int }](x T) { _ = cap(x /* ERROR invalid argument */ ) }
-func _[T interface{ type chan int }](x T) { _ = cap(x) }
-func _[T interface{ type []byte, chan int }](x T) { _ = cap(x) }
+func _[T interface{ ~int }](x T) { _ = cap(x /* ERROR invalid argument */ ) }
+func _[T interface{ ~string | ~[]byte | ~int }](x T) { _ = cap(x /* ERROR invalid argument */ ) }
+func _[T interface{ ~string }](x T) { _ = cap(x /* ERROR invalid argument */ ) }
+func _[T interface{ ~[10]int }](x T) { _ = cap(x) }
+func _[T interface{ ~[]byte }](x T) { _ = cap(x) }
+func _[T interface{ ~map[int]int }](x T) { _ = cap(x /* ERROR invalid argument */ ) }
+func _[T interface{ ~chan int }](x T) { _ = cap(x) }
+func _[T interface{ ~[]byte | ~chan int }](x T) { _ = cap(x) }
// range iteration
for range x /* ERROR cannot range */ {}
}
-func _[T interface{ type string, []string }](x T) {
+func _[T interface{ ~string | ~[]string }](x T) {
for range x {}
for i := range x { _ = i }
for i, _ := range x { _ = i }
}
-func _[T interface{ type string, []rune, map[int]rune }](x T) {
+func _[T interface{ ~string | ~[]rune | ~map[int]rune }](x T) {
for _, e := range x { _ = e }
for i, e := range x { _ = i; _ = e }
}
-func _[T interface{ type string, []rune, map[string]rune }](x T) {
+func _[T interface{ ~string | ~[]rune | ~map[string]rune }](x T) {
for _, e := range x { _ = e }
for i, e := range x /* ERROR must have the same key type */ { _ = e }
}
-func _[T interface{ type string, chan int }](x T) {
+func _[T interface{ ~string | ~chan int }](x T) {
for range x {}
for i := range x { _ = i }
for i, _ := range x { _ = i } // TODO(gri) should get an error here: channels only return one value
}
-func _[T interface{ type string, chan<-int }](x T) {
+func _[T interface{ ~string | ~chan<-int }](x T) {
for i := range x /* ERROR send-only channel */ { _ = i }
}
}
}
-func _[T interface{type int}](x T) {
+func _[T interface{~int}](x T) {
_ = x /* ERROR not an interface */ .(int)
switch x /* ERROR not an interface */ .(type) {
}