and may explain why type inference fails in unusual code situations.
But by and large these rules can be ignored when writing Go code:
type inference is designed to mostly "work as expected",
and the unification rules are fine-tuned accordingly.
</p>

<p>
Type unification is controlled by a <i>matching mode</i>, which may
be <i>exact</i> or <i>loose</i>.
As unification recursively descends a composite type structure,

)

type flagFunc func(string)

func (f flagFunc) String() string     { return "" }
func (f flagFunc) Set(s string) error { f(s); return nil }

func init() {
	cmdEdit.Run = runEdit // break init cycle

	cmdEdit.Flag.Var(flagFunc(flagGodebug), "godebug", "")
	cmdEdit.Flag.Var(flagFunc(flagDropGodebug), "dropgodebug", "")
	cmdEdit.Flag.Var(flagFunc(flagRequire), "require", "")