go/src/cmd/compile/internal/noder/irgen.go

var versionErrorRx …

// checkFiles configures and runs the types2 checker on the given
// parsed source files and then returns the result.
// The map result value indicates which closures are generated from the bodies of range function loops.
func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info, map[*syntax.FuncLit]bool) { … }

type cycleFinder …

// hasCycle reports whether typ is part of an anonymous interface cycle.
func (f *cycleFinder) hasCycle(typ *types2.Interface) bool { … }

// visit recursively walks typ0 to check any referenced interface types.
func (f *cycleFinder) visit(typ0 types2.Type) bool { … }