|  | // errorcheck | 
|  |  | 
|  | // Copyright 2022 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 | 
|  |  | 
|  | // Self recursion. | 
|  | type i interface{ m() interface{ i } } // ERROR "invalid recursive type" | 
|  | type _ interface{ i }                  // no redundant error | 
|  |  | 
|  | // Mutual recursion. | 
|  | type j interface{ m() interface{ k } } // ERROR "invalid recursive type" | 
|  | type k interface{ m() interface{ j } } | 
|  |  | 
|  | // Both self and mutual recursion. | 
|  | type ( | 
|  | a interface { // ERROR "invalid recursive type" | 
|  | m() interface { | 
|  | a | 
|  | b | 
|  | } | 
|  | } | 
|  | b interface { | 
|  | m() interface { | 
|  | a | 
|  | b | 
|  | } | 
|  | } | 
|  | ) | 
|  |  | 
|  | // Self recursion through other types. | 
|  | func _() { type i interface{ m() *interface{ i } } }        // ERROR "invalid recursive type" | 
|  | func _() { type i interface{ m() []interface{ i } } }       // ERROR "invalid recursive type" | 
|  | func _() { type i interface{ m() [0]interface{ i } } }      // ERROR "invalid recursive type" | 
|  | func _() { type i interface{ m() chan interface{ i } } }    // ERROR "invalid recursive type" | 
|  | func _() { type i interface{ m() map[interface{ i }]int } } // ERROR "invalid recursive type" | 
|  | func _() { type i interface{ m() map[int]interface{ i } } } // ERROR "invalid recursive type" | 
|  | func _() { type i interface{ m() func(interface{ i }) } }   // ERROR "invalid recursive type" | 
|  | func _() { type i interface{ m() func() interface{ i } } }  // ERROR "invalid recursive type" | 
|  | func _() { | 
|  | type i interface { // ERROR "invalid recursive type" | 
|  | m() struct{ i interface{ i } } | 
|  | } | 
|  | } |