"-debug=1A" is accepted, even though "1A" is an invalid identifier
test case:
svn://svn.kuehne.cn/dstress/complex/command_line (command_line_debug_05)

"-debug123" is interpreted as "-debug"
test case:
svn://svn.kuehne.cn/dstress/complex/command_line (command_line_debug_06)

"-debugABC" is interpreted as "-debug"
test case:
svn://svn.kuehne.cn/dstress/complex/command_line (command_line_debug_07)

the command line:
dmd -c ""
is accepted if the file ".d" is present and creates the object file ".o"
test case:
svn://svn.kuehne.cn/dstress/complex/command_line (command_line_null_source_03)

the command line:
dmd  ""
is accepted if the file ".d" is present and fails with the message:
> /usr/bin/ld: cannot open output file /usr/lib/crt1.o: Permission denied colletc2: ld returned 1 exit status
> --- errorlevel 1
test case:
svn://svn.kuehne.cn/dstress/complex/command_line (command_line_null_source_04)

Thomas

in addition the cmd:
dmd "..d"
is accepted if a file named "..d" is present and containts a module name.
Dmd attempts to write the output file ".."
(in linux terms thats the file system entry of the parent directory)

test case:
svn://svn.kuehne.cn/dstress/complex/ (command_line_null_source_0[56])

Thomas