1 files changed, 24 insertions, 3 deletions
diff --git a/test/typeparam/settable.go b/test/typeparam/settable.go
index 3bd141f784..7532953a77 100644
--- a/test/typeparam/settable.go
+++ b/test/typeparam/settable.go
@@ -11,7 +11,24 @@ import (
 	"strconv"
 )
 
-func fromStrings3[T any](s []string, set func(*T, string)) []T {
+type Setter[B any] interface {
+        Set(string)
+	type *B
+}
+
+func fromStrings1[T any, PT Setter[T]](s []string) []T {
+        result := make([]T, len(s))
+        for i, v := range s {
+                // The type of &result[i] is *T which is in the type list
+                // of Setter, so we can convert it to PT.
+                p := PT(&result[i])
+                // PT has a Set method.
+                p.Set(v)
+        }
+        return result
+}
+
+func fromStrings2[T any](s []string, set func(*T, string)) []T {
         results := make([]T, len(s))
         for i, v := range s {
                 set(&results[i], v)
@@ -30,8 +47,12 @@ func (p *Settable) Set(s string) {
 }
 
 func main() {
-        s := fromStrings3([]string{"1"},
-                func(p *Settable, s string) { p.Set(s) })
+        s := fromStrings1[Settable, *Settable]([]string{"1"})
+        if len(s) != 1 || s[0] != 1 {
+                panic(fmt.Sprintf("got %v, want %v", s, []int{1}))
+        }
+
+        s = fromStrings2([]string{"1"}, func(p *Settable, s string) { p.Set(s) })
         if len(s) != 1 || s[0] != 1 {
                 panic(fmt.Sprintf("got %v, want %v", s, []int{1}))
         }