type methodSet map[string]*Func

// recvString returns a string representation of recv of the form "T", "*T",
// "T[A, ...]", "*T[A, ...]" or "BADRECV" (if not a proper receiver type).
func recvString(recv ast.Expr) string {
	switch t := recv.(type) {
	case *ast.Ident:
		return t.Name
	case *ast.StarExpr:
		return "*" + recvString(t.X)
	case *ast.IndexExpr:
		// Generic type with one parameter.