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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/token"
. "go/types"
"strings"
"testing"
)
func TestInstantiateEquality(t *testing.T) {
emptySignature := NewSignatureType(nil, nil, nil, nil, nil, false)
tests := []struct {
src string
name1 string
targs1 []Type
name2 string
targs2 []Type
wantEqual bool
}{
{
"package basictype; type T[P any] int",
"T", []Type{Typ[Int]},
"T", []Type{Typ[Int]},
true,
},
{
"package differenttypeargs; type T[P any] int",
"T", []Type{Typ[Int]},
"T", []Type{Typ[String]},
false,
},
{
"package typeslice; type T[P any] int",
"T", []Type{NewSlice(Typ[Int])},
"T", []Type{NewSlice(Typ[Int])},
true,
},
{
// interface{interface{...}} is equivalent to interface{...}
"package equivalentinterfaces; type T[P any] int",
"T", []Type{
NewInterfaceType([]*Func{NewFunc(token.NoPos, nil, "M", emptySignature)}, nil),
},
"T", []Type{
NewInterfaceType(
nil,
[]Type{
NewInterfaceType([]*Func{NewFunc(token.NoPos, nil, "M", emptySignature)}, nil),
},
),
},
true,
},
{
// int|string is equivalent to string|int
"package equivalenttypesets; type T[P any] int",
"T", []Type{
NewInterfaceType(nil, []Type{
NewUnion([]*Term{NewTerm(false, Typ[Int]), NewTerm(false, Typ[String])}),
}),
},
"T", []Type{
NewInterfaceType(nil, []Type{
NewUnion([]*Term{NewTerm(false, Typ[String]), NewTerm(false, Typ[Int])}),
}),
},
true,
},
{
"package basicfunc; func F[P any]() {}",
"F", []Type{Typ[Int]},
"F", []Type{Typ[Int]},
true,
},
{
"package funcslice; func F[P any]() {}",
"F", []Type{NewSlice(Typ[Int])},
"F", []Type{NewSlice(Typ[Int])},
true,
},
{
"package funcwithparams; func F[P any](x string) float64 { return 0 }",
"F", []Type{Typ[Int]},
"F", []Type{Typ[Int]},
true,
},
{
"package differentfuncargs; func F[P any](x string) float64 { return 0 }",
"F", []Type{Typ[Int]},
"F", []Type{Typ[String]},
false,
},
{
"package funcequality; func F1[P any](x int) {}; func F2[Q any](x int) {}",
"F1", []Type{Typ[Int]},
"F2", []Type{Typ[Int]},
false,
},
{
"package funcsymmetry; func F1[P any](x P) {}; func F2[Q any](x Q) {}",
"F1", []Type{Typ[Int]},
"F2", []Type{Typ[Int]},
false,
},
}
for _, test := range tests {
pkg, err := pkgForMode(".", test.src, nil, 0)
if err != nil {
t.Fatal(err)
}
t.Run(pkg.Name(), func(t *testing.T) {
ctxt := NewContext()
T1 := pkg.Scope().Lookup(test.name1).Type()
res1, err := Instantiate(ctxt, T1, test.targs1, false)
if err != nil {
t.Fatal(err)
}
T2 := pkg.Scope().Lookup(test.name2).Type()
res2, err := Instantiate(ctxt, T2, test.targs2, false)
if err != nil {
t.Fatal(err)
}
if gotEqual := res1 == res2; gotEqual != test.wantEqual {
t.Errorf("%s == %s: %t, want %t", res1, res2, gotEqual, test.wantEqual)
}
})
}
}
func TestInstantiateNonEquality(t *testing.T) {
const src = "package p; type T[P any] int"
pkg1, err := pkgForMode(".", src, nil, 0)
if err != nil {
t.Fatal(err)
}
pkg2, err := pkgForMode(".", src, nil, 0)
if err != nil {
t.Fatal(err)
}
// We consider T1 and T2 to be distinct types, so their instances should not
// be deduplicated by the context.
T1 := pkg1.Scope().Lookup("T").Type().(*Named)
T2 := pkg2.Scope().Lookup("T").Type().(*Named)
ctxt := NewContext()
res1, err := Instantiate(ctxt, T1, []Type{Typ[Int]}, false)
if err != nil {
t.Fatal(err)
}
res2, err := Instantiate(ctxt, 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 = `package 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(P)", "func (*T[int]).m(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 := pkgForMode(".", src, nil, 0)
if err != nil {
t.Fatal(err)
}
typ := NewPointer(pkg.Scope().Lookup("X").Type())
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 = `package p
type T[P any] struct{}
func (T[P]) m() {}
var _ T[int]
`
pkg, err := pkgForMode(".", src, nil, 0)
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
}