go/src/cmd/go/internal/run/run.go

var CmdRun …

func init() { … }

func runRun(ctx context.Context, cmd *base.Command, args []string) { … }

// shouldUseOutsideModuleMode returns whether 'go run' will load packages in
// module-aware mode, ignoring the go.mod file in the current directory. It
// returns true if the first argument contains "@", does not begin with "-"
// (resembling a flag) or end with ".go" (a file). The argument must not be a
// local or absolute file path.
//
// These rules are slightly different than other commands. Whether or not
// 'go run' uses this mode, it interprets arguments ending with ".go" as files
// and uses arguments up to the last ".go" argument to comprise the package.
// If there are no ".go" arguments, only the first argument is interpreted
// as a package path, since there can be only one package.
func shouldUseOutsideModuleMode(args []string) bool { … }

// buildRunProgram is the action for running a binary that has already
// been compiled. We ignore exit status.
func buildRunProgram(b *work.Builder, ctx context.Context, a *work.Action) error { … }