To visit errors sequentially, type @w{@kbd{C-x `}} (@code{next-error}), or equivalently @kbd{M-g M-n} or @kbd{M-g n}.  This command can be invoked from any buffer, not just a Compilation mode buffer.  The first time you invoke it after a compilation, it visits the locus of the first error message.  Each subsequent <del>@w{@kbd{C-x `}}</del> <ins>@w{@kbd{M-g M-n}}</ins> visits the next error, in a similar fashion.  If you visit a specific error with @key{RET} or a mouse click in the @file{*compilation*} buffer, subsequent <del>@w{@kbd{C-x `}}</del> <ins>@w{@kbd{M-g M-n}}</ins> commands advance from there.  When <del>@w{@kbd{C-x `}}</del> <ins>@w{@kbd{M-g M-n}}</ins> finds no more error messages to visit, it signals an error.  @w{@kbd{C-u <del>C-x `}}</del> <ins>M-g M-n}}</ins> starts again from the beginning of the compilation buffer, and visits the first locus.