You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: objectpath.go
    path of file: ./repos/sealer/vendor/golang.org/x/tools/go/types/objectpath
    
    the code of the file until where you have to start completion: // Copyright 2018 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 objectpath defines a naming scheme for types.Objects
// (that is, named entities in Go programs) relative to their enclosing
// package.
//
// Type-checker objects are canonical, so they are usually identified by
// their address in memory (a pointer), but a pointer has meaning only
// within one address space. By contrast, objectpath names allow the
// identity of an object to be sent from one program to another,
// establishing a correspondence between types.Object variables that are
// distinct but logically equivalent.
//
// A single object may have multiple paths. In this example,
//
//	type A struct{ X int }
//	type B A
//
// the field X has two paths due to its membership of both A and B.
// The For(obj) function always returns one of these paths, arbitrarily
// but consistently.
package objectpath

import (
	"fmt"
	"go/types"
	"sort"
	"strconv"
	"strings"
	_ "unsafe"

	"golang.org/x/tools/internal/typeparams"
	"golang.org/x/tools/internal/typesinternal"
)

// A Path is an opaque name that identifies a types.Object
// relative to its package. Conceptually, the name consists of a
// sequence of destructuring operations applied to the package scope
// to obtain the original object.
// The name does not include the package itself.
type Path string

// Encoding
//
// An object path is a textual and (with training) human-readable encoding
// of a sequence of destructuring operators, starting from a types.Package.
// The sequences represent a path through the package/object/type graph.
// We classify these operators by their type:
//
//	PO package->object	Package.Scope.Lookup
//	OT  object->type 	Object.Type
//	TT    type->type 	Type.{Elem,Key,Params,Results,Underlying} [EKPRU]
//	TO   type->object	Type.{At,Field,Method,Obj} [AFMO]
//
// All valid paths start with a package and end at an object
// and thus may be defined by the regular language:
//
//	objectpath = PO (OT TT* TO)*
//
// The concrete encoding follows directly:
//   - The only PO operator is Package.Scope.Lookup, which requires an identifier.
//   - The only OT operator is Object.Type,
//     which we encode as '.' because dot cannot appear in an identifier.
//   - The TT operators are encoded as [EKPRUTC];
//     one of these (TypeParam) requires an integer operand,
//     which is encoded as a string of decimal digits.
//   - The TO operators are encoded as [AFMO];
//     three of these (At,Field,Method) require an integer operand,
//     which is encoded as a string of decimal digits.
//     These indices are stable across different representations
//     of the same package, even source and export data.
//     The indices used are implementation specific and may not correspond to
//     the argument to the go/types function.
//
// In the example below,
//
//	package p
//
//	type T interface {
//		f() (a string, b struct{ X int })
//	}
//
// field X has the path "T.UM0.RA1.F0",
// representing the following sequence of operations:
//
//	p.Lookup("T")					T
//	.Type().Underlying().Method(0).			f
//	.Type().Results().At(1)				b
//	.Type().Field(0)					X
//
// The encoding is not maximally compact---every R or P is
// followed by an A, for example---but this simplifies the
// encoder and decoder.
const (
	// object->type operators
	opType = '.' // .Type()		  (Object)

	// type->type operators
	opElem       = 'E' // .Elem()		        (Pointer, Slice, Array, Chan, Map)
	opKey        = 'K' // .Key()		        (Map)
	opParams     = 'P' // .Params()		      (Signature)
	opResults    = 'R' // .Results()	      (Signature)
	opUnderlying = 'U' // .Underlying()	    (Named)
	opTypeParam  = 'T' // .TypeParam
    
func (enc *Encoder) For(obj types.Object) (Path, error) {
	pkg := obj.Pkg()

	// This table lists the cases of interest.
	//
	// Object				Action
	// ------                               ------
	// nil					reject
	// builtin				reject
	// pkgname				reject
	// label				reject
	// var
	//    package-level			accept
	//    func param/result			accept
	//    local				reject
	//    struct field			accept
	// const
	//    package-level			accept
	//    local				reject
	// func
	//    package-level			accept
	//    init functions			reject
	//    concrete method			accept
	//    interface method			accept
	// type
	//    package-level			accept
	//    local				reject
	//
	// The only accessible package-level objects are members of pkg itself.
	//
	// The cases are handled in four steps:
	//
	// 1. reject nil and builtin
	// 2. accept package-level objects
	// 3. reject obviously invalid objects
	// 4. search the API for the path to the param/result/field/method.

	// 1. reference to nil or builtin?
	if pkg == nil {
		return "", fmt.Errorf("predeclared %s has no path", obj)
	}
	scope := pkg.Scope()

	// 2. package-level object?
	if scope.Lookup(obj.Name()) == obj {
		// Only exported objects (and non-exported types) have a path.
		// Non-exported types may be referenced by other objects.
		if _, ok := obj.(*types.TypeName); !ok && !obj.Exported() {
			return "", fmt.Errorf("no path for non-exported %v", obj)
		}
		return Path(obj.Name()), nil
	}

	// 3. Not a package-level object.
	//    Reject obviously non-viable cases.
	switch obj := obj.(type) {
	case *types.TypeName:
		if _, ok := obj.Type().(*typeparams.TypeParam); !ok {
			// With the exception of type parameters, only package-level type names
			// have a path.
			return "", fmt.Errorf("no path for %v", obj)
		}
	case *types.Const, // Only package-level constants have a path.
		*types.Label,   // Labels are function-local.
		*types.PkgName: // PkgNames are file-local.
		return "", fmt.Errorf("no path for %v", obj)

	case *types.Var:
		// Could be:
		// - a field (obj.IsField())
		// - a func parameter or result
		// - a local var.
		// Sadly there is no way to distinguish
		// a param/result from a local
		// so we must proceed to the find.

	case *types.Func:
		// A func, if not package-level, must be a method.
		if recv := obj.Type().(*types.Signature).Recv(); recv == nil {
			return "", fmt.Errorf("func is not a method: %v", obj)
		}

		if path, ok := enc.concreteMethod(obj); ok {
			// Fast path for concrete methods that avoids looping over scope.
			return path, nil
		}

	default:
		panic(obj)
	}

	// 4. Search the API for the path to the var (field/param/result) or method.

	// First inspect package-level named types.
	// In the presence of path aliases, these give
	// the best paths because non-types may
	// refer to types, but not the reverse.
	empty := make([]byte, 0, 48) // initial space
	objs := enc.scopeObjects(scope)
	for _, o := range objs {
		tname, ok := o.(*types.TypeName)
		if !ok {
			continue // handle non-types in second pass
		}

		path := append(empty, o.Name()...)
		path = append(path, opType)

		T := o.Type()

		if tname.IsAlias() {
			// type alias
			if r := find(obj, T, path, nil); r != nil {
				return Path(r), nil
			}
		} else {
			if named, _ := T.(*types.Named); named != nil {
				if r := findTypeParam(obj, typeparams.ForNamed(named), path, nil); r != nil {
					// generic named type
					return Path(r), nil
				}
			}
			// defined (named) type
			if r := find(obj, T.Underlying(), append(path, opUnderlying), nil); r != nil {
				return Path(r), nil
			}
		}
	}

	// Then inspect everything else:
	// non-types, and declared methods of defined types.
	for _, o := range objs {
		path := append(empty, o.Name()...)
		if _, ok := o.(*types.TypeName); !ok {
			if o.Exported() {
				// exported non-type (const, var, func)
				if r := find(obj, o.Type(), append(path, opType), nil); r != nil {
					return Path(r), nil
				}
			}
			continue
		}

		// Inspect declared methods of defined types.
		if T, ok := o.Type().(*types.Named); ok {
			path = append(path, opType)
			if !enc.skipMethodSorting {
				// Note that method index here is always with respect
				// to canonical ordering of methods, regardless of how
				// they appear in the underlying type.
				for i, m := range enc.namedMethods(T) {
					path2 := appendOpArg(path, opMethod, i)
					if m == obj {
						return Path(path2), nil // found declared method
					}
					if r := find(obj, m.Type(), append(path2, opType), nil); r != nil {
						return Path(r), nil
					}
				}
			} else {
				// This branch must match the logic in the branch above, using go/types
				// APIs without sorting.
				for i := 0; i < T.NumMethods(); i++ {
					m := T.Method(i)
					path2 := appendOpArg(path, opMethod, i)
					if m == obj {
						return Path(path2), nil // found declared method
					}
					if r := find(obj, m.Type(), append(path2, opType), nil); r != nil {
						return Path(r), nil
					}
				}
			}
		}
	}

	return "", fmt.Errorf("can't find path for %v in %s", obj, pkg.Path())
}