| bytes | Package bytes implements functions for the manipulation of byte slices. |
| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| 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/ast | Package ast declares the types used to represent syntax trees for Go packages. |
| go/build | Package build gathers information about Go packages. |
| go/constant | Package constant implements Values representing untyped Go constants and their corresponding operations. |
| go/parser | Package parser implements a parser for Go source files. |
| go/printer | Package printer implements printing of AST nodes. |
| 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/cmd/guru/serial | Package serial defines the guru's schema for -json output. |
| golang.org/x/tools/go/ast/astutil | Package astutil contains common utilities for working with the Go AST. |
| golang.org/x/tools/go/buildutil | Package buildutil provides utilities related to the go/build package in the standard library. |
| golang.org/x/tools/go/loader | Package loader loads a complete Go program from source code, parsing and type-checking the initial packages plus their transitive closure of dependencies. |
| golang.org/x/tools/go/types/typeutil | Package typeutil defines various utilities for types, such as Map, a hash table that maps types.Type to any value. |
| golang.org/x/tools/imports | Package imports implements a Go pretty-printer (like package "go/format") that also adds or removes import statements as necessary. |
| golang.org/x/tools/refactor/importgraph | Package importgraph computes the forward and reverse import dependency graphs for all packages in a Go workspace. |
| 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. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| runtime/pprof | Package pprof writes runtime profiling data in the format expected by the pprof visualization tool. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| unicode/utf8 | Package utf8 implements functions and constants to support text encoded in UTF-8. |