diff --git a/src/cmd/go2go/testdata/go2path/src/alg/alg.go2 b/src/cmd/go2go/testdata/go2path/src/alg/alg.go2
index 593610d2b1..3d1b420f60 100644
--- a/src/cmd/go2go/testdata/go2path/src/alg/alg.go2
+++ b/src/cmd/go2go/testdata/go2path/src/alg/alg.go2
@@ -5,10 +5,10 @@
 // Package alg provides basic algorithms.
 package alg
 
-import "contracts"
+import "constraints"
 
 // Max returns the maximum of two values of some ordered type.
-func Max(type T contracts.Ordered)(a, b T) T {
+func Max(type T constraints.Ordered)(a, b T) T {
 	if a < b {
 		return b
 	}
@@ -16,7 +16,7 @@ func Max(type T contracts.Ordered)(a, b T) T {
 }
 
 // Min returns the minimum of two values of some ordered type.
-func Min(type T contracts.Ordered)(a, b T) T {
+func Min(type T constraints.Ordered)(a, b T) T {
 	if a < b {
 		return a
 	}
diff --git a/src/cmd/go2go/testdata/go2path/src/contracts/contracts.go2 b/src/cmd/go2go/testdata/go2path/src/constraints/constraints.go2
similarity index 90%
rename from src/cmd/go2go/testdata/go2path/src/contracts/contracts.go2
rename to src/cmd/go2go/testdata/go2path/src/constraints/constraints.go2
index 0d2fc8ebed..ee757c4af6 100644
--- a/src/cmd/go2go/testdata/go2path/src/contracts/contracts.go2
+++ b/src/cmd/go2go/testdata/go2path/src/constraints/constraints.go2
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package contracts defines some useful type bounds.
-package contracts
+// Package constraints defines some useful type constraints.
+package constraints
 
 // Ordered permits any ordered type: any type that supports
 // the operations <, <=, >=, >, as well as == and !=.
diff --git a/src/cmd/go2go/testdata/go2path/src/gsort/gsort.go2 b/src/cmd/go2go/testdata/go2path/src/gsort/gsort.go2
index f1c97bee18..3558f194fa 100644
--- a/src/cmd/go2go/testdata/go2path/src/gsort/gsort.go2
+++ b/src/cmd/go2go/testdata/go2path/src/gsort/gsort.go2
@@ -8,11 +8,11 @@ package gsort
 import (
 	"sort"
 
-	"contracts"
+	"constraints"
 )
 
 // orderedSlice is a slice of values of some ordered type.
-type orderedSlice(type Elem contracts.Ordered) []Elem
+type orderedSlice(type Elem constraints.Ordered) []Elem
 
 // orderedSlice implements sort.Interface.
 
@@ -30,7 +30,7 @@ func (s orderedSlice(Elem)) Less(i, j int) bool {
 func (s orderedSlice(Elem)) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
 
 // OrderedSlice sorts a slice of any ordered type in ascending order.
-func OrderedSlice(type Elem contracts.Ordered)(s []Elem) {
+func OrderedSlice(type Elem constraints.Ordered)(s []Elem) {
 	sort.Sort(orderedSlice(Elem)(s))
 }
 
diff --git a/src/cmd/go2go/testdata/go2path/src/gsort/gsort_test.go2 b/src/cmd/go2go/testdata/go2path/src/gsort/gsort_test.go2
index 412a946f73..9be9fa9e45 100644
--- a/src/cmd/go2go/testdata/go2path/src/gsort/gsort_test.go2
+++ b/src/cmd/go2go/testdata/go2path/src/gsort/gsort_test.go2
@@ -9,7 +9,7 @@ import (
 	"sort"
 	"testing"
 
-	"contracts"
+	"constraints"
 	"slices"
 )
 
@@ -31,7 +31,7 @@ func TestSortOrderedStrings(t *testing.T) {
 	testOrdered(t, strs, sort.Strings)
 }
 
-func testOrdered(type Elem contracts.Ordered)(t *testing.T, s []Elem, sorter func([]Elem)) {
+func testOrdered(type Elem constraints.Ordered)(t *testing.T, s []Elem, sorter func([]Elem)) {
 	s1 := make([]Elem, len(s))
 	copy(s1, s)
 	s2 := make([]Elem, len(s))
diff --git a/src/cmd/go2go/testdata/go2path/src/orderedmap/orderedmap.go2 b/src/cmd/go2go/testdata/go2path/src/orderedmap/orderedmap.go2
index 49d2b4ac1b..d997e4ab4f 100644
--- a/src/cmd/go2go/testdata/go2path/src/orderedmap/orderedmap.go2
+++ b/src/cmd/go2go/testdata/go2path/src/orderedmap/orderedmap.go2
@@ -11,7 +11,7 @@ import (
 	"context"
 
 	"chans"
-	"contracts"
+	"constraints"
 )
 
 // Map is an ordered map.
@@ -37,7 +37,7 @@ func New(type K, V)(compare func(K, K) int) *Map(K, V) {
 // NewOrdered returns a new map whose key is an ordered type.
 // This is like New, but does not require providing a compare function.
 // The map compare function uses the obvious key ordering.
-func NewOrdered(type K contracts.Ordered, V interface{})() *Map(K, V) {
+func NewOrdered(type K constraints.Ordered, V interface{})() *Map(K, V) {
 	return New(K, V)(func(k1, k2 K) int {
 		switch {
 		case k1 < k2:
diff --git a/src/cmd/go2go/testdata/go2path/src/slices/slices.go2 b/src/cmd/go2go/testdata/go2path/src/slices/slices.go2
index 69036c1586..ab687d6e20 100644
--- a/src/cmd/go2go/testdata/go2path/src/slices/slices.go2
+++ b/src/cmd/go2go/testdata/go2path/src/slices/slices.go2
@@ -8,7 +8,7 @@ package slices
 
 import (
 	"alg"
-	"contracts"
+	"constraints"
 )
 
 // Equal reports whether two slices are equal: the same length and all
@@ -76,7 +76,7 @@ func Filter(type Elem)(s []Elem, f func(Elem) bool) []Elem {
 
 // Max returns the maximum element in a slice of some ordered type.
 // If the slice is empty it returns the zero value of the element type.
-func Max(type Elem contracts.Ordered)(s []Elem) Elem {
+func Max(type Elem constraints.Ordered)(s []Elem) Elem {
 	if len(s) == 0 {
 		var zero Elem
 		return zero
@@ -86,7 +86,7 @@ func Max(type Elem contracts.Ordered)(s []Elem) Elem {
 
 // Min returns the minimum element in a slice of some ordered type.
 // If the slice is empty it returns the zero value of the element type.
-func Min(type Elem contracts.Ordered)(s []Elem) Elem {
+func Min(type Elem constraints.Ordered)(s []Elem) Elem {
 	if len(s) == 0 {
 		var zero Elem
 		return zero
diff --git a/src/cmd/go2go/testdata/go2path/src/slices/slices_test.go2 b/src/cmd/go2go/testdata/go2path/src/slices/slices_test.go2
index 0e4b57aaa5..5c2cdeeaf2 100644
--- a/src/cmd/go2go/testdata/go2path/src/slices/slices_test.go2
+++ b/src/cmd/go2go/testdata/go2path/src/slices/slices_test.go2
@@ -9,7 +9,7 @@ import (
 	"strings"
 	"testing"
 
-	"contracts"
+	"constraints"
 )
 
 func TestEqual(t *testing.T) {
@@ -42,7 +42,7 @@ func TestEqual(t *testing.T) {
 	}
 }
 
-func offByOne(type Elem contracts.Integer)(a, b Elem) bool {
+func offByOne(type Elem constraints.Integer)(a, b Elem) bool {
 	return a == b + 1 || a == b - 1
 }