Imports of package aliases

PathSynopsis
go/astPackage ast declares the types used to represent syntax trees for Go packages.
go/parserPackage parser implements a parser for Go source files.
go/tokenPackage token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates).
go/typesPackage types declares the data types and implements the algorithms for type-checking of Go packages.