--- /dev/null
+// Copyright 2010 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 a
+
+import (
+ "encoding/xml"
+ "fmt"
+ "io"
+)
+
+type T int
+
+func (T) Scan(x fmt.ScanState, c byte) {} // want `should have signature Scan\(fmt\.ScanState, rune\) error`
+
+func (T) Format(fmt.State, byte) {} // want `should have signature Format\(fmt.State, rune\)`
+
+type U int
+
+func (U) Format(byte) {} // no error: first parameter must be fmt.State to trigger check
+
+func (U) GobDecode() {} // want `should have signature GobDecode\(\[\]byte\) error`
+
+// Test rendering of type names such as xml.Encoder in diagnostic.
+func (U) MarshalXML(*xml.Encoder) {} // want `method MarshalXML\(\*xml.Encoder\) should...`
+
+func (U) UnmarshalXML(*xml.Decoder, xml.StartElement) error { // no error: signature matches xml.Unmarshaler
+ return nil
+}
+
+func (U) WriteTo(w io.Writer) {} // want `method WriteTo\(w io.Writer\) should have signature WriteTo\(io.Writer\) \(int64, error\)`
+
+func (T) WriteTo(w io.Writer, more, args int) {} // ok - clearly not io.WriterTo
+
+type I interface {
+ ReadByte() byte // want `should have signature ReadByte\(\) \(byte, error\)`
+}