Concat: nicer test messages

Author: earthboundkid

src/slices/slices_test.go

@@ -1113,7 +1113,8 @@ func TestConcat(t *testing.T) {
 }
 
 func TestConcat_too_large(t *testing.T) {
-	type b [0]byte
+	// Use zero length element to minimize memory in testing
+	type void struct{}
 	cases := []struct {
 		lengths     []int
 		shouldPanic bool
@@ -1149,9 +1150,9 @@ func TestConcat_too_large(t *testing.T) {
 	}
 	for _, tc := range cases {
 		var r any
-		var ss [][]b
+		ss := make([][]void, 0, len(tc.lengths))
 		for _, l := range tc.lengths {
-			s := make([]b, l)
+			s := make([]void, l)
 			ss = append(ss, s)
 		}
 		func() {