go/test/typeparam/ifaceconv.go
Dan Scales 501725032c [dev.typeparams] cmd/compile: handle derived types that are converted to interfaces
Up to this point, we were only handling typeparams that were converted
to empty or non-empty interfaces. But we have a dictionary entry for
each derived type (i.e. type derived from typeparams) as well. So, when
doing a conversion, look for the source type in both the type params and
derived types of the generic info, and then use the appropriate
dictionary entry.

Added some cases to ifaceconv.go (e.g. converting []T to an empty
interface).

Change-Id: I7bbad0128bec20ccccd93ae1d65c1ffd44ca79a0
Reviewed-on: https://go-review.googlesource.com/c/go/+/333011
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2021-07-07 17:40:11 +00:00

83 lines
1.7 KiB
Go

// run -gcflags=-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.
// Test that we can convert type parameters to both empty
// and nonempty interfaces, and named and nonnamed versions
// thereof.
package main
import "fmt"
type E interface{}
func f[T any](x T) interface{} {
var i interface{} = x
return i
}
func fs[T any](x T) interface{} {
y := []T{x}
var i interface{} = y
return i
}
func g[T any](x T) E {
var i E = x
return i
}
type C interface {
foo() int
}
type myInt int
func (x myInt) foo() int {
return int(x+1)
}
func h[T C](x T) interface{foo() int} {
var i interface{foo()int} = x
return i
}
func i[T C](x T) C {
var i C = x // conversion in assignment
return i
}
func j[T C](t T) C {
return C(t) // explicit conversion
}
func js[T any](x T) interface{} {
y := []T{x}
return interface{}(y)
}
func main() {
if got, want := f[int](7), 7; got != want {
panic(fmt.Sprintf("got %d want %d", got, want))
}
if got, want := fs[int](7), []int{7}; got.([]int)[0] != want[0] {
panic(fmt.Sprintf("got %d want %d", got, want))
}
if got, want := g[int](7), 7; got != want {
panic(fmt.Sprintf("got %d want %d", got, want))
}
if got, want := h[myInt](7).foo(), 8; got != want {
panic(fmt.Sprintf("got %d want %d", got, want))
}
if got, want := i[myInt](7).foo(), 8; got != want {
panic(fmt.Sprintf("got %d want %d", got, want))
}
if got, want := j[myInt](7).foo(), 8; got != want {
panic(fmt.Sprintf("got %d want %d", got, want))
}
if got, want := js[int](7), []int{7}; got.([]int)[0] != want[0] {
panic(fmt.Sprintf("got %d want %d", got, want))
}
}