Package compare contains code for generating comparison routines for structs, strings and interfaces.

Package devirtualize implements two "devirtualization" optimization passes: - "Static" devirtualization which replaces interface method calls with direct concrete-type method calls where possible.

package importer implements Import for gc-generated object files.

Package loopvar applies the proper variable capture, according to experiment, flags, language version, etc.

Package rangefunc rewrites range-over-func to code that doesn't use range-over-funcs.

Package rttype allows the compiler to share type information with the runtime.

Package types declares the data types and implements the algorithms for type-checking of Go packages.