$ perl5.16.1.exe -Mdiagnostics reallyperlconfusingerror.pl
Having no space between pattern and following word is deprecated at
        reallyperlconfusingerror.pl line 5 (#1)
    (D syntax)

    You had a word that isn't a regex modifier immediately following
    a pattern without an intervening space.  If you are trying to use
    the /le flags on a substitution, use /el instead.  Otherwise, add
    white space between the pattern and following word to eliminate
    the warning.  As an example of the latter, the two constructs:

     $a =~ m/$foo/sand $bar
     $a =~ m/$foo/s and $bar

    both currently mean the same thing, but it is planned to disallow
    the first form in Perl 5.18.  And,

     $a =~ m/$foo/and $bar

    will be disallowed too.

Bareword found where operator expected at reallyperlconfusingerror.pl line 5, near "print "a - b -Q"
  (Might be a runaway multi-line -- string starting on line 3) (#2)
    (S syntax) The Perl lexer knows whether to expect a term or an operator.
    If it sees what it knows to be a term when it was expecting to see an
    operator, it gives you this warning.  Usually it indicates that an
    operator or delimiter was omitted, such as a semicolon.

        (Do you need to predeclare print?)
String found where operator expected at reallyperlconfusingerror.pl line 5, at
        end of line (#2)
        (Missing semicolon on previous line?)

syntax error at reallyperlconfusingerror.pl line 5, near "print "a - b -Q"
Can't find string terminator '"' anywhere before EOF at reallyperlconfusingerror.pl line 5 (#3)
    (F) Probably means you had a syntax error.  Common reasons include:

        A keyword is misspelled.
        A semicolon is missing.
        A comma is missing.
        An opening or closing parenthesis is missing.
        An opening or closing brace is missing.
        A closing quote is missing.

    Often there will be another error message associated with the syntax
    error giving more information.  (Sometimes it helps to turn on -w.)
    The error message itself often tells you where it was in the line when
    it decided to give up.  Sometimes the actual error is several tokens
    before this, because Perl is good at understanding random input.
    Occasionally the line number may be misleading, and once in a blue moon
    the only way to figure out what's triggering the error is to call
    perl -c repeatedly, chopping away half the program each time to see
    if the error went away.  Sort of the cybernetic version of 20 questions.

Uncaught exception from user code:
        syntax error at reallyperlconfusingerror.pl line 5, near "print "a - b -Q"
        Can't find string terminator '"' anywhere before EOF at reallyperlconfusingerror.pl line 5.