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go/test/typeparam/issue50417.go
Robert Griesemer b8248fab89 go/types, types2: disable field accesses through type parameters
This is a feature that is not understood well enough and may have
subtle repercussions impacting future changes. Disable for Go 1.18.

The actual change is trivial: disable a branch through a flag.
The remaining changes are adjustments to tests.

Fixes #51576.

Change-Id: Ib77b038b846711a808315a8889b3904e72367bce
Reviewed-on: https://go-review.googlesource.com/c/go/+/391135
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
2022-03-09 21:26:42 +00:00

147 lines
1.5 KiB
Go

// run
// Copyright 2022 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 main
func main() {}
// Field accesses through type parameters are disabled
// until we have a more thorough understanding of the
// implications on the spec. See issue #51576.
/*
type Sf struct {
f int
}
func f0[P Sf](p P) {
_ = p.f
p.f = 0
}
func f0t[P ~struct{ f int }](p P) {
_ = p.f
p.f = 0
}
var _ = f0[Sf]
var _ = f0t[Sf]
func f1[P interface {
~struct{ f int }
m()
}](p P) {
_ = p.f
p.f = 0
p.m()
}
var _ = f1[Sfm]
type Sm struct{}
func (Sm) m() {}
type Sfm struct {
f int
}
func (Sfm) m() {}
func f2[P interface {
Sfm
m()
}](p P) {
_ = p.f
p.f = 0
p.m()
}
var _ = f2[Sfm]
// special case: core type is a named pointer type
type PSfm *Sfm
func f3[P interface{ PSfm }](p P) {
_ = p.f
p.f = 0
}
var _ = f3[PSfm]
// special case: core type is an unnamed pointer type
func f4[P interface{ *Sfm }](p P) {
_ = p.f
p.f = 0
}
var _ = f4[*Sfm]
type A int
type B int
type C float64
type Int interface {
*Sf | A
*Sf | B
}
func f5[P Int](p P) {
_ = p.f
p.f = 0
}
var _ = f5[*Sf]
type Int2 interface {
*Sf | A
any
*Sf | C
}
func f6[P Int2](p P) {
_ = p.f
p.f = 0
}
var _ = f6[*Sf]
type Int3 interface {
Sf
~struct{ f int }
}
func f7[P Int3](p P) {
_ = p.f
p.f = 0
}
var _ = f7[Sf]
type Em1 interface {
*Sf | A
}
type Em2 interface {
*Sf | B
}
type Int4 interface {
Em1
Em2
any
}
func f8[P Int4](p P) {
_ = p.f
p.f = 0
}
var _ = f8[*Sf]
*/