| bytes | Package bytes implements functions for the manipulation of byte slices. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| go/constant | Package constant implements Values representing untyped Go constants and their corresponding operations. |
| go/token | Package token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates). |
| go/types | Package types declares the data types and implements the algorithms for type-checking of Go packages. |
| golang.org/x/tools/container/intsets | Package intsets provides Sparse, a compact and fast representation for sparse sets of int values. |
| golang.org/x/tools/go/callgraph | Package callgraph defines the call graph and various algorithms and utilities to operate on it. |
| golang.org/x/tools/go/ssa | Package ssa defines a representation of the elements of Go programs (packages, types, functions, variables and constants) using a static single-assignment (SSA) form intermediate representation (IR) for the bodies of functions. |
| golang.org/x/tools/go/types/typeutil | Package typeutil defines various utilities for types, such as Map, a mapping from types.Type to interface{} values. |
| io | Package io provides basic interfaces to I/O primitives. |
| log | Package log implements a simple logging package. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| os/exec | Package exec runs external commands. |
| reflect | Package reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| runtime/debug | Package debug contains facilities for programs to debug themselves while they are running. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| time | Package time provides functionality for measuring and displaying time. |