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// 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 types_test
import (
. "go/types"
"strings"
"testing"
)
func TestInstantiateEquality(t *testing.T) {
const src = genericPkg + "p; type T[P any] int"
pkg, err := pkgFor(".", src, nil)
if err != nil {
t.Fatal(err)
}
T := pkg.Scope().Lookup("T").Type().(*Named)
// Instantiating the same type twice should result in pointer-equivalent
// instances.
env := NewEnvironment()
res1, err := Instantiate(env, T, []Type{Typ[Int]}, false)
if err != nil {
t.Fatal(err)
}
res2, err := Instantiate(env, T, []Type{Typ[Int]}, false)
if err != nil {
t.Fatal(err)
}
if res1 != res2 {
t.Errorf("first instance (%s) not pointer-equivalent to second instance (%s)", res1, res2)
}
}
func TestInstantiateNonEquality(t *testing.T) {
const src = genericPkg + "p; type T[P any] int"
pkg1, err := pkgFor(".", src, nil)
if err != nil {
t.Fatal(err)
}
pkg2, err := pkgFor(".", src, nil)
if err != nil {
t.Fatal(err)
}
// We consider T1 and T2 to be distinct types, so their instances should not
// be deduplicated by the environment.
T1 := pkg1.Scope().Lookup("T").Type().(*Named)
T2 := pkg2.Scope().Lookup("T").Type().(*Named)
env := NewEnvironment()
res1, err := Instantiate(env, T1, []Type{Typ[Int]}, false)
if err != nil {
t.Fatal(err)
}
res2, err := Instantiate(env, T2, []Type{Typ[Int]}, false)
if err != nil {
t.Fatal(err)
}
if res1 == res2 {
t.Errorf("instance from pkg1 (%s) is pointer-equivalent to instance from pkg2 (%s)", res1, res2)
}
if Identical(res1, res2) {
t.Errorf("instance from pkg1 (%s) is identical to instance from pkg2 (%s)", res1, res2)
}
}
func TestMethodInstantiation(t *testing.T) {
const prefix = genericPkg + `p
type T[P any] struct{}
var X T[int]
`
tests := []struct {
decl string
want string
}{
{"func (r T[P]) m() P", "func (T[int]).m() int"},
{"func (r T[P]) m(P)", "func (T[int]).m(int)"},
{"func (r T[P]) m() func() P", "func (T[int]).m() func() int"},
{"func (r T[P]) m() T[P]", "func (T[int]).m() T[int]"},
{"func (r T[P]) m(T[P])", "func (T[int]).m(T[int])"},
{"func (r T[P]) m(T[P], P, string)", "func (T[int]).m(T[int], int, string)"},
{"func (r T[P]) m(T[P], T[string], T[int])", "func (T[int]).m(T[int], T[string], T[int])"},
}
for _, test := range tests {
src := prefix + test.decl
pkg, err := pkgFor(".", src, nil)
if err != nil {
t.Fatal(err)
}
typ := pkg.Scope().Lookup("X").Type().(*Named)
obj, _, _ := LookupFieldOrMethod(typ, false, pkg, "m")
m, _ := obj.(*Func)
if m == nil {
t.Fatalf(`LookupFieldOrMethod(%s, "m") = %v, want func m`, typ, obj)
}
if got := ObjectString(m, RelativeTo(pkg)); got != test.want {
t.Errorf("instantiated %q, want %q", got, test.want)
}
}
}
func TestImmutableSignatures(t *testing.T) {
const src = genericPkg + `p
type T[P any] struct{}
func (T[P]) m() {}
var _ T[int]
`
pkg, err := pkgFor(".", src, nil)
if err != nil {
t.Fatal(err)
}
typ := pkg.Scope().Lookup("T").Type().(*Named)
obj, _, _ := LookupFieldOrMethod(typ, false, pkg, "m")
if obj == nil {
t.Fatalf(`LookupFieldOrMethod(%s, "m") = %v, want func m`, typ, obj)
}
// Verify that the original method is not mutated by instantiating T (this
// bug manifested when subst did not return a new signature).
want := "func (T[P]).m()"
if got := stripAnnotations(ObjectString(obj, RelativeTo(pkg))); got != want {
t.Errorf("instantiated %q, want %q", got, want)
}
}
// Copied from errors.go.
func stripAnnotations(s string) string {
var b strings.Builder
for _, r := range s {
// strip #'s and subscript digits
if r < '₀' || '₀'+10 <= r { // '₀' == U+2080
b.WriteRune(r)
}
}
if b.Len() < len(s) {
return b.String()
}
return s
}
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