// errorcheck // 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 type I interface{ M(int) } type T struct{} type T2 struct{} func (*T2) m(int) type T3 struct{} func (*T3) M(string) {} type T4 struct{} func (*T4) M(int) type T5 struct{} func (T5) m(int) {} type T6 struct{} func (T6) m(int) string { return "" } func f(I) func g() { f(new(T)) // ERROR "cannot use new\(T\) \(.*type \*T\) as I value in argument to f: \*T does not implement I \(missing method M\)" var i I i = new(T) // ERROR "cannot use new\(T\) \(.*type \*T\) as I value in assignment: \*T does not implement I \(missing method M\)" i = I(new(T)) // ERROR "cannot convert new\(T\) \(.*type \*T\) to type I: \*T does not implement I \(missing method M\)" i = new(T2) // ERROR "cannot use new\(T2\) \(.*type \*T2\) as I value in assignment: \*T2 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)" i = new(T3) // ERROR "cannot use new\(T3\) \(.*type \*T3\) as I value in assignment: \*T3 does not implement I \(wrong type for method M\)\n\t\thave M\(string\)\n\t\twant M\(int\)" i = T4{} // ERROR "cannot use T4\{\} \(.*type T4\) as I value in assignment: T4 does not implement I \(method M has pointer receiver\)" i = new(I) // ERROR "cannot use new\(I\) \(.*type \*I\) as I value in assignment: \*I does not implement I \(type \*I is pointer to interface, not interface\)" _ = i.(*T2) // ERROR "impossible type assertion: i.\(\*T2\)\n\t\*T2 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)" _ = i.(*T3) // ERROR "impossible type assertion: i.\(\*T3\)\n\t\*T3 does not implement I \(wrong type for method M\)\n\t\thave M\(string\)\n\t\twant M\(int\)" _ = i.(T5) // ERROR ""impossible type assertion: i.\(T5\)\n\tT5 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)" _ = i.(T6) // ERROR "impossible type assertion: i.\(T6\)\n\tT6 does not implement I \(missing method M\)\n\t\thave m\(int\) string\n\t\twant M\(int\)" var t *T4 t = i // ERROR "cannot use i \(variable of interface type I\) as \*T4 value in assignment: need type assertion" _ = t }