1
0
mirror of https://github.com/golang/go synced 2024-11-11 19:51:37 -07:00
go/test/switch6.go
Robert Griesemer 254c497e5c cmd/compile, types2: better error message for invalid type assertion
This CL addresses the 2nd part of the issue below.

- For types2, now use the same error messages as the compiler in this case.
- Make the mechanism for reporting clarifying error messages handle the case
  where we don't have additional position information.
- Provide context information (type assertion vs type switch).

Fixes #49005.

Change-Id: I4eeaf4f0c3f2f8735b63993778f58d713fef21ee
Reviewed-on: https://go-review.googlesource.com/c/go/+/356512
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Robert Findley <rfindley@google.com>
2021-10-19 17:01:35 +00:00

47 lines
1.1 KiB
Go

// errorcheck
// Copyright 2016 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.
// Check the compiler's switch handling that happens
// at typechecking time.
// This must be separate from other checks,
// because errors during typechecking
// prevent other errors from being discovered.
package main
// Verify that type switch statements with impossible cases are detected by the compiler.
func f0(e error) {
switch e.(type) {
case int: // ERROR "impossible type switch case: (int\n\t)?e \(.*type error\) cannot have dynamic type int \(missing Error method\)"
}
}
// Verify that the compiler rejects multiple default cases.
func f1(e interface{}) {
switch e {
default:
default: // ERROR "multiple defaults( in switch)?"
}
switch e.(type) {
default:
default: // ERROR "multiple defaults( in switch)?"
}
}
type I interface {
Foo()
}
type X int
func (*X) Foo() {}
func f2() {
var i I
switch i.(type) {
case X: // ERROR "impossible type switch case: (X\n\t)?i \(.*type I\) cannot have dynamic type X \(Foo method has pointer receiver\)"
}
}