Error in compile

[JohnNichols]

write(*,9)

where 9 is an undefined format does not throw an error or warning.  I had a stack drawing a straight line in the output, deleted 9 and it all kept compiling, pretty sure that is not a good idea.

Whoever said arithmetic if's are a bad idea is a Fortran Saint now. 

[Steve_Lionel]

t.f90(1): error #6052: This label has not been defined as a FORMAT label.   [9]
write(*,9)
--------^
compilation aborted for t.f90 (code 1)

D:\Projects>

How about providing a compilable source that reproduces the problem? These minimal snippets waste everyone's time.