diff --git a/src/cmd/compile/internal/types2/testdata/check/builtins.go2 b/src/cmd/compile/internal/types2/testdata/check/builtins.go2
index 3918d836b5..5bb67efec9 100644
--- a/src/cmd/compile/internal/types2/testdata/check/builtins.go2
+++ b/src/cmd/compile/internal/types2/testdata/check/builtins.go2
@@ -7,19 +7,19 @@
 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] () {
diff --git a/src/cmd/compile/internal/types2/testdata/check/issues.go2 b/src/cmd/compile/internal/types2/testdata/check/issues.go2
index f0a7b24748..59dd4ae465 100644
--- a/src/cmd/compile/internal/types2/testdata/check/issues.go2
+++ b/src/cmd/compile/internal/types2/testdata/check/issues.go2
@@ -57,7 +57,7 @@ func _() {
 // 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 */ ]{}
@@ -65,7 +65,7 @@ func _[P any]() {
 
 // This is the original (simplified) program causing the same issue.
 type Unsigned interface {
-	type uint
+	~uint
 }
 
 type T2[U Unsigned] struct {
@@ -156,7 +156,7 @@ type inf2[T any] struct{ inf2 /* ERROR illegal cycle */ [T] }
 // 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)
 }
 
@@ -168,12 +168,12 @@ func _() {
 // 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
 	}
@@ -182,19 +182,19 @@ func Sum[T interface{type int, string}](s []T) (sum T) {
 
 // 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
@@ -203,24 +203,24 @@ func _[T interface{type int}](x T) {
 
 // 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()
 }
@@ -232,7 +232,7 @@ func _[T interface{ type func() }](f T) {
 // 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
 
diff --git a/src/cmd/compile/internal/types2/testdata/check/linalg.go2 b/src/cmd/compile/internal/types2/testdata/check/linalg.go2
index 0d27603a58..efc090a1d1 100644
--- a/src/cmd/compile/internal/types2/testdata/check/linalg.go2
+++ b/src/cmd/compile/internal/types2/testdata/check/linalg.go2
@@ -9,10 +9,10 @@ import "math"
 // 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 {
@@ -42,14 +42,14 @@ func AbsDifference[T NumericAbs[T]](a, b 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
diff --git a/src/cmd/compile/internal/types2/testdata/check/tinference.go2 b/src/cmd/compile/internal/types2/testdata/check/tinference.go2
index a53fde0a2a..2fdb39ca7a 100644
--- a/src/cmd/compile/internal/types2/testdata/check/tinference.go2
+++ b/src/cmd/compile/internal/types2/testdata/check/tinference.go2
@@ -8,28 +8,28 @@ import "strconv"
 
 type any interface{}
 
-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
@@ -37,7 +37,7 @@ func _() {
 	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
@@ -45,14 +45,14 @@ func _() {
 	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
@@ -60,11 +60,11 @@ func _() {
 
 // 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
@@ -80,7 +80,7 @@ var _ = Double(MySlice{1})
 
 type Setter[B any] interface {
 	Set(string)
-	type *B
+	~*B
 }
 
 func FromStrings[T interface{}, PT Setter[T]](s []string) []T {
diff --git a/src/cmd/compile/internal/types2/testdata/check/typeinst2.go2 b/src/cmd/compile/internal/types2/testdata/check/typeinst2.go2
index 1096bb42eb..37745dfcba 100644
--- a/src/cmd/compile/internal/types2/testdata/check/typeinst2.go2
+++ b/src/cmd/compile/internal/types2/testdata/check/typeinst2.go2
@@ -148,15 +148,15 @@ func _[T any](r R2[T, int], p *R2[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.
@@ -164,23 +164,24 @@ type _ interface {
 // 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|~int /* ERROR duplicate term 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} | ~struct /* ERROR duplicate term */ {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
 }
 
@@ -189,15 +190,15 @@ func double[T interface{type MyInt, MyString}](x T) T {
 // 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 {
@@ -246,7 +247,7 @@ var _ = f12[float64]
 
 type I0_ interface {
 	E0
-	type int
+	~int
 }
 
 func f0_[T I0_]()
diff --git a/src/cmd/compile/internal/types2/testdata/check/typeparams.go2 b/src/cmd/compile/internal/types2/testdata/check/typeparams.go2
index badda01105..4074ef17ea 100644
--- a/src/cmd/compile/internal/types2/testdata/check/typeparams.go2
+++ b/src/cmd/compile/internal/types2/testdata/check/typeparams.go2
@@ -52,22 +52,22 @@ func swapswap[A, B any](a A, b B) (A, B) {
 
 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
@@ -95,48 +95,48 @@ var _ = f3[int, rune, bool](1, struct{x rune}{}, nil)
 // 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
 
@@ -144,7 +144,7 @@ func _[T interface{}](x T) {
         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 }
@@ -156,23 +156,23 @@ func _[T interface{ type string, []string }](x T) {
 }
 
 
-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 }
 }
 
@@ -400,7 +400,7 @@ func _[T any](x T) {
 	}
 }
 
-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) {
 	}