| bytes | Package bytes implements functions for the manipulation of byte slices. |
| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| errors | Package errors implements functions to manipulate errors. |
| flag | Package flag implements command-line flag parsing. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| 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/expect | Package expect provides support for interpreting structured comments in Go source code (including go.mod and go.work files) as test expectations. |
| golang.org/x/tools/go/packages | Package packages loads Go packages for inspection and analysis. |
| golang.org/x/tools/internal/gocommand | Package gocommand is a helper for calling the go command. |
| golang.org/x/tools/internal/proxydir | Package proxydir provides functions for writing module data to a directory in proxy format, so that it can be used as a module proxy by setting GOPROXY="file://<dir>". |
| golang.org/x/tools/internal/testenv | Package testenv contains helper functions for skipping tests based on which tools are present in the environment. |
| 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. |
| path | Package path implements utility routines for manipulating slash-separated paths. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| reflect | Package reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types. |
| regexp | Package regexp implements regular expression search. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| testing | Package testing provides support for automated testing of Go packages. |