Package analysis defines the interface between a modular static analysis and an analysis driver program. Background ¶ A static analysis is a function that inspects a package of Go code and reports a set of diagnostics (typically mistakes in the code), and perhaps produces other results as well, such as suggested refactorings or other facts. An analysis that reports mistakes is informally called a "checker". For example, the printf checker reports mistakes in fmt.Printf format strings. A "modular" analysis is one that inspects one package at a time but can save information from a lower-level package and use it when inspecting a higher-level package, analogous to separate compilation in a toolchain. The printf checker is modular: when it discovers that a function such as log.Fatalf delegates to fmt.Printf, it records this fact, and checks calls to that function too, including calls made from another package.…