func (a *Alias) Underlying() Type { return unalias(a).Underlying() }

// Origin returns the generic Alias type of which a is an instance.
// If a is not an instance of a generic alias, Origin returns a.
func (a *Alias) Origin() *Alias { return a.orig }

// TypeParams returns the type parameters of the alias type a, or nil.
// A generic Alias and its instances have the same type parameters.

// uninstantiated generic type.
func ConvertibleTo(V, T Type) bool {
	x := operand{mode: value, typ: V}
	return x.convertibleTo(nil, T, nil) // check not needed for non-constant x
}

// Implements reports whether type V implements interface T.
//
// The behavior of Implements is unspecified if V is Typ[Invalid] or an uninstantiated
// generic type.
func Implements(V Type, T *Interface) bool {

For details see the [language spec](/ref/spec#For_statements).

<!-- go.dev/issue/46477, CL 566856, CL 586955, CL 586956 -->
Go 1.23 includes preview support for [generic type aliases](/issue/46477).

package test

import (
	"internal/testenv"
	"os"
	"path/filepath"
	"regexp"
	"testing"
)

// TestInst tests that only one instantiation of Sort is created, even though generic
// Sort is used for multiple pointer types across two packages.
func TestInst(t *testing.T) {
	testenv.MustHaveGoBuild(t)
	testenv.MustHaveGoRun(t)

	// Build ptrsort.go, which uses package mysort.
	var output []byte

package main

var decOps = []opData{}

var decBlocks = []blockData{}

func init() {
	archs = append(archs, arch{
		name:    "dec",
		ops:     decOps,
		blocks:  decBlocks,
		generic: true,
	})

The methods [Alias.Origin], [Alias.SetTypeParams], [Alias.TypeParams],

		//	callee: "mult.MultClosure.func1",
		//},
	}

	testPGODevirtualize(t, dir, want, preProfFileName)
}

// Regression test for https://go.dev/issue/65615. If a target function changes
// from non-generic to generic we can't devirtualize it (don't know the type
// parameters), but the compiler should not crash.
func TestLookupFuncGeneric(t *testing.T) {
	wd, err := os.Getwd()
	if err != nil {

//     type TypeParamType struct {
//         Tag     itag // typeParamType
//         Name    stringOff
//         PkgPath stringOff
//     }
//
//     // Instantiation of a generic type (like List[T2] or List[int])
//     type InstanceType struct {
//         Tag     itag // instanceType
//         Pos     pos
//         TypeArgs []typeOff
//         BaseType typeOff
//     }
//

		SrcInst  = pkg.Scope().Lookup("Inst").Type()
		UserInst = mustInstantiate(b, G, Typ[Int])
	)

	tests := []struct {
		name string
		typ  Type
	}{
		{"nongeneric", T},
		{"generic", G},
		{"src instance", SrcInst},
		{"user instance", UserInst},
	}

	b.Run("Underlying", func(b *testing.B) {
		for _, test := range tests {
			b.Run(test.name, func(b *testing.B) {

package main

var dec64Ops = []opData{}

var dec64Blocks = []blockData{}

func init() {
	archs = append(archs, arch{
		name:    "dec64",
		ops:     dec64Ops,
		blocks:  dec64Blocks,
		generic: true,
	})