Give a code warning for unused defines

ID:2482197
 
Jun 28 2019, 8:18 pm
Applies to:DM Language
Status: Open
Issue hasn't been assigned a status value.
We have warnings for unused variables but I don't believe we have warnings for unused defines. Is there any reason we don't?
Jun 28 2019, 9:04 pm
Unused defines are inconsequential. And sometimes intentional.
Jun 28 2019, 9:05 pm
Why?
Jun 28 2019, 9:09 pm
Don't they slow down compile time slightly?
Jun 28 2019, 9:36 pm
Inconsequentially.

Also basically every general purpose library would generate a huge number of warnings especially when naming bitflags using #defines, and forward-thinking stuff like utility macros.
Jun 29 2019, 6:17 pm
Don't know about unused, but warnings about double defines would be nice.
Jul 5 2019, 12:46 pm
defines are a stack, this is a feature that can be used intentionally for code maintenance benefits between modules or libraries.

#define blah "foo"
world << blah //outputs foo
#define blah "bar"
world << blah //outputs bar
#undef blah
world << blah //outputs foo
#undef blah
world << blah //compile error.


When it comes to preventing namespace collision, this allows modules or libraries to not worry about conflicting with a define by the main code by just unsetting it at the end. Even if the main code defined the define before the module/library, it's value will be preserved.