}

// printPackageMu synchronizes the printing of type-checked package files in
// the typecheckFiles function.
//
// Without synchronization, package files may be interleaved during concurrent
// type-checking.
var printPackageMu sync.Mutex

// typecheckFiles typechecks the given package files.
func typecheckFiles(path string, filenames []string, importer Importer) (*Package, error) {
	// Parse package files.

}

// printPackageMu synchronizes the printing of type-checked package files in
// the typecheckFiles function.
//
// Without synchronization, package files may be interleaved during concurrent
// type-checking.
var printPackageMu sync.Mutex

// typecheckFiles typechecks the given package files.
func typecheckFiles(path string, filenames []string, importer Importer) (*Package, error) {
	fset := token.NewFileSet()