add option to emit warnings for unused functions/macros/variables/types

[Book-reader]

my current project has a lot of utility functions and macros that have since been phased out due to refactoring, but because I have taken multiple month long breaks from my project & all my old and new function declarations are mixed together it is difficult for me to easily tell what functions I am currently using and which ones I can remove. This is is absolutely my fault, but it would be nice to have a compiler flag that I could use to print all unused functions and macros

there is "warnings": ["no-unused"] in the default project.json and a corresponding PROJECT_VIEW_TYPE_WARNINGS_USED option, but that doesn't look like it's used anywhere

[lerno]

Do we want this, or do we want to use the setting for different levels of checking? I was thinking that maybe it's better to have three levels of warnings instead of specific warnings like this.

[Book-reader]

so something along the lines of --validation=lenient for no unused warnings, --validation=strict for unused warnings, and --validation=obnoxious for unused errors? or did you mean something like a --unused flag with for example none for no unused warnings, some for unused variables & functions, and all for all unused things, and then the --validation level could affect whether --unused emits warnings or errors?

I do agree though that there probably shouldn't be an option to individually turn specific unused warnings on or off.

[lerno]

Something along those lines yes.

[xnhp0320]

sometimes the code is just copied from previous code with changed parameters, and it is easily forgot to use the newly variable to replace the old parameters in the copied code. Adding this warnings can be helpful to find these bugs.