func renameImportPath(f *ast.File, renames ...string) {
	m := makeRenameMap(renames...)
	ast.Inspect(f, func(n ast.Node) bool {
		switch n := n.(type) {
		case *ast.ImportSpec:
			if n.Path.Kind != token.STRING {
				panic("invalid import path")
			}
			m.rename(&n.Path.Value)
			return false
		}
		return true
	})
}

func (obj *Object) Pos() token.Pos {
	name := obj.Name
	switch d := obj.Decl.(type) {
	case *Field:
		for _, n := range d.Names {
			if n.Name == name {
				return n.Pos()
			}
		}
	case *ImportSpec:
		if d.Name != nil && d.Name.Name == name {
			return d.Name.Pos()
		}
		return d.Path.Pos()
	case *ValueSpec:
		for _, n := range d.Names {
			if n.Name == name {
				return n.Pos()
			}
		}

		return 1 << nFuncType
	case *ast.GenDecl:
		return 1 << nGenDecl
	case *ast.GoStmt:
		return 1 << nGoStmt
	case *ast.Ident:
		return 1 << nIdent
	case *ast.IfStmt:
		return 1 << nIfStmt
	case *ast.ImportSpec:
		return 1 << nImportSpec
	case *ast.IncDecStmt:
		return 1 << nIncDecStmt
	case *ast.IndexExpr:
		return 1 << nIndexExpr
	case *ast.IndexListExpr:
		return 1 << nIndexListExpr
	case *ast.InterfaceType:

		}

		// Add special dot-import declaration:
		//    import . "·this·"
		var decls []ast.Decl
		decls = append(decls, &ast.GenDecl{
			Tok: token.IMPORT,
			Specs: []ast.Spec{
				&ast.ImportSpec{
					Name: &ast.Ident{Name: "."},
					Path: &ast.BasicLit{
						Kind:  token.STRING,
						Value: strconv.Quote(thispkg),
					},
				},
			},
		})

			}
			fmt.Fprintf(w, "{%q, funcTag, %d},\n", decl.Name.Name, interner.intern(decl.Type))
		case *ast.GenDecl:
			if decl.Tok == token.IMPORT {
				if len(decl.Specs) != 1 || decl.Specs[0].(*ast.ImportSpec).Path.Value != "\"unsafe\"" {
					log.Fatal("runtime cannot import other package")
				}
				continue
			}
			if decl.Tok != token.VAR {
				log.Fatal("unhandled declaration kind", decl.Tok)
			}

	// Implicits maps nodes to their implicitly declared objects, if any.
	// The following node and object types may appear:
	//
	//     node               declared object
	//
	//     *ast.ImportSpec    *PkgName for imports without renames
	//     *ast.CaseClause    type-specific *Var for each type switch case clause (incl. default)
	//     *ast.Field         anonymous parameter *Var (incl. unnamed results)
	//

	case *RangeStmt:
		if n.Key != nil {
			Walk(v, n.Key)
		}
		if n.Value != nil {
			Walk(v, n.Value)
		}
		Walk(v, n.X)
		Walk(v, n.Body)

	// Declarations
	case *ImportSpec:
		if n.Doc != nil {
			Walk(v, n.Doc)
		}
		if n.Name != nil {
			Walk(v, n.Name)
		}
		Walk(v, n.Path)
		if n.Comment != nil {
			Walk(v, n.Comment)
		}

	case *ValueSpec:

		r.filterType(nil, t.Key)
		r.filterType(nil, t.Value)
	case *ast.ChanType:
		r.filterType(nil, t.Value)
	}
}

func (r *reader) filterSpec(spec ast.Spec) bool {
	switch s := spec.(type) {
	case *ast.ImportSpec:
		// always keep imports so we can collect them
		return true
	case *ast.ValueSpec:
		s.Values = filterExprList(s.Values, token.IsExported, true)
		if len(s.Values) > 0 || s.Type == nil && len(s.Values) == 0 {

	}

	hasEmbed := false
	for _, decl := range info.parsed.Decls {
		d, ok := decl.(*ast.GenDecl)
		if !ok {
			continue
		}
		for _, dspec := range d.Specs {
			spec, ok := dspec.(*ast.ImportSpec)
			if !ok {
				continue
			}
			quoted := spec.Path.Value
			path, err := strconv.Unquote(quoted)
			if err != nil {
				return fmt.Errorf("parser returned invalid quoted string: <%s>", quoted)
			}

			for _, d := range decls {
				if d != nil {
					decls[i] = d
					i++
				}
			}
			decls = decls[0:i]
		}
	}

	// Collect import specs from all package files.
	var imports []*ImportSpec
	if mode&FilterImportDuplicates != 0 {
		seen := make(map[string]bool)
		for _, filename := range filenames {
			f := pkg.Files[filename]
			for _, imp := range f.Imports {