| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| go/ast | Package ast declares the types used to represent syntax trees for Go packages. |
| go/parser | Package parser implements a parser for Go source files. |
| go/token | Package token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates). |
| golang.org/x/tools/go/analysis | Package analysis defines the interface between a modular static analysis and an analysis driver program. |
| golang.org/x/tools/internal/packagepath | Package packagepath provides metadata operations on package path strings. |
| golang.org/x/tools/internal/stdlib | Package stdlib provides a table of all exported symbols in the standard library, along with the version at which they first appeared. |
| golang.org/x/tools/internal/versions | |
| os | Package os provides a platform-independent interface to operating system functionality. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |