1// errorcheck
2
3// Copyright 2019 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7package p
8
9import "io"
10
11// Alan's initial report.
12
13type I interface { f(); String() string }
14type J interface { g(); String() string }
15
16type IJ1 = interface { I; J }
17type IJ2 = interface { f(); g(); String() string }
18
19var _ = (*IJ1)(nil) == (*IJ2)(nil) // static assert that IJ1 and IJ2 are identical types
20
21// The canonical example.
22
23type ReadWriteCloser interface { io.ReadCloser; io.WriteCloser }
24
25// Some more cases.
26
27type M interface { m() }
28type M32 interface { m() int32 }
29type M64 interface { m() int64 }
30
31type U1 interface { m() }
32type U2 interface { m(); M }
33type U3 interface { M; m() }
34type U4 interface { M; M; M }
35type U5 interface { U1; U2; U3; U4 }
36
37type U6 interface { m(); m() } // ERROR "duplicate method .*m"
38type U7 interface { M32; m() } // ERROR "duplicate method .*m"
39type U8 interface { m(); M32 } // ERROR "duplicate method .*m"
40type U9 interface { M32; M64 } // ERROR "duplicate method .*m"
41