stack/stack.go
func (c *Call) merge(r *Call) Call {
	return Call{
		SrcPath:      c.SrcPath,
		Line:         c.Line,
		Func:         c.Func,
		Args:         c.Args.merge(&r.Args),
		LocalSrcPath: c.LocalSrcPath,
		IsStdlib:     c.IsStdlib,
	}
}
func (c *Call) merge(r *Call) Call {
	return Call{
		SrcPath:      c.SrcPath,
		Line:         c.Line,
		Func:         c.Func,
		Args:         c.Args.merge(&r.Args),
		LocalSrcPath: c.LocalSrcPath,
		IsStdlib:     c.IsStdlib,
	}
}
// merge merges two similar Call, zapping out differences.