Bug or correct behavior?

[Derek Clegg]

Given this simple makefile

start: dir/a.c
dir/%.c: %.c | dir ; cp $< $@
dir/%.c: foo.h
dir: ; mkdir $@
a.c foo.h: ; touch $@

I'm seeing the following when I run make:

touch a.c
mkdir dir
cp a.c dir/a.c

This is surprising; my expectation is that the dependency "dir/%c.:  
foo.h" would force "foo.h" to be created as well.  Is this a bug or  
correct behavior?  My reading of the manual has led me to believe it's  
a bug, but since it's not explicitly addressed in the manual, I'm not  
completely sure.

Thanks very much for any responses.

Derek