| // Copyright 2021 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package p |
| |
| // parameterized types with self-recursive constraints |
| type ( |
| T1 /* ERROR illegal cycle */ [P T1[P]] interface{} |
| T2 /* ERROR illegal cycle */ [P, Q T2[P, Q]] interface{} |
| T3[P T2[P, Q], Q interface{ ~string }] interface{} |
| |
| T4a /* ERROR illegal cycle */ [P T4a[P]] interface{ ~int } |
| T4b /* ERROR illegal cycle */ [P T4b[int]] interface{ ~int } |
| T4c /* ERROR illegal cycle */ [P T4c[string]] interface{ ~int } |
| |
| // mutually recursive constraints |
| T5 /* ERROR illegal cycle */ [P T6[P]] interface{ int } |
| T6[P T5[P]] interface{ int } |
| ) |
| |
| // verify that constraints are checked as expected |
| var ( |
| _ T1[int] |
| _ T2[int, string] |
| _ T3[int, string] |
| ) |
| |
| // test case from issue |
| |
| type Eq /* ERROR illegal cycle */ [a Eq[a]] interface { |
| Equal(that a) bool |
| } |
