if name := s.Name.Name; token.IsExported(name) {
			r.filterType(r.lookupType(s.Name.Name), s.Type)
			return true
		} else if IsPredeclared(name) {
			if r.shadowedPredecl == nil {
				r.shadowedPredecl = make(map[string]bool)
			}
			r.shadowedPredecl[name] = true
		}
	}
	return false
}

// copyConstType returns a copy of typ with position pos.
// typ must be a valid constant type.

	order  int      // sort order of const and var declarations (when we can't use a name)
	types  map[string]*namedType
	funcs  methodSet

	// support for package-local shadowing of predeclared types
	shadowedPredecl map[string]bool
	fixmap          map[string][]*ast.InterfaceType
}

func (r *reader) isVisible(name string) bool {
	return r.mode&AllDecls != 0 || token.IsExported(name)
}