go/test/fixedbugs/issue48471.go
Robert Griesemer 6019a52d4d go/types, types2: better error message when using *interface instead of interface
- detect *interface case and report specific error
- replaced switch with sequence of if's for more clarity
- fixed isInterfacePtr: it applies to all interfaces, incl.
  type parameters
- reviewed/fixed all uses of isInterfacePtr
- adjusted error messages to be consistently of the format
  "type %s is pointer to interface, not interface"

Fixes #48312.

Change-Id: Ic3c8cfcf93ad57ecdb60f6a727cce9e1aa4afb5d
Reviewed-on: https://go-review.googlesource.com/c/go/+/376914
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
2022-01-10 22:48:40 +00:00

42 lines
1.8 KiB
Go

// errorcheck -G=3
// 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)
func f(I)
func g() {
f(new(T)) // ERROR "cannot use new\(T\) \(.*type \*T\) as type I in argument to f:\n\t\*T does not implement I \(missing M method\)"
var i I
i = new(T) // ERROR "cannot use new\(T\) \(.*type \*T\) as type I in assignment:\n\t\*T does not implement I \(missing M method\)"
i = I(new(T)) // ERROR "cannot convert new\(T\) \(.*type \*T\) to type I:\n\t\*T does not implement I \(missing M method\)"
i = new(T2) // ERROR "cannot use new\(T2\) \(.*type \*T2\) as type I in assignment:\n\t\*T2 does not implement I \(missing M method\)\n\t\thave m\(int\)\n\t\twant M\(int\)"
i = new(T3) // ERROR "cannot use new\(T3\) \(.*type \*T3\) as type I in assignment:\n\t\*T3 does not implement I \(wrong type for M method\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
i = T4{} // ERROR "cannot use T4\{\} \(.*type T4\) as type I in assignment:\n\tT4 does not implement I \(M method has pointer receiver\)"
i = new(I) // ERROR "cannot use new\(I\) \(.*type \*I\) as type I in assignment:\n\t\*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 \(missing M method\)\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 \(wrong type for M method\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
var t *T4
t = i // ERROR "cannot use i \(variable of type I\) as type \*T4 in assignment:\n\tneed type assertion"
_ = i
}