sync: Select, Combine work with more channel types

sync/select.go

@@ -4,9 +4,15 @@ import "slices"
 import "context"
 import "reflect"
 
+// ChannelRecv is a type constraint that includes all channel types that can be
+// recieved from.
+type ChannelRecv[T any] interface {
+	~chan T | ~<- chan T
+}
+
 // A type-safe wrapper around reflect.Select. Taken from:
 // https://stackoverflow.com/questions/19992334
-func Select[T any] (ctx context.Context, channels ...chan T) (int, T, bool) {
+func Select[T any, C ChannelRecv[T]] (ctx context.Context, channels ...C) (int, T, bool) {
 	var zero T
 
 	// add all channels as select cases
@@ -39,11 +45,12 @@ func Select[T any] (ctx context.Context, channels ...chan T) (int, T, bool) {
 		return chosen, ret, true
 	}
 	return chosen, zero, false
+	
 }
 
 // Combine returns a channel that continuously returns the result of the select
 // until all input sources are exhauste, or the context is canceled.
-func Combine[T any] (ctx context.Context, channels ...chan T) <- chan T {
+func Combine[T any, C ChannelRecv[T]] (ctx context.Context, channels ...C) <- chan T {
 	channel := make(chan T)
 	// our silly slection routine
 	go func () {