> Now that I think of it, maybe IDEs should highlight non-const references in function calls.

This is a great idea. When I type `ls` in a shell, I get important information from the colors of the output: one color for normal files, another for executables, another for directories, etc.

This would work well for parameter types, even if it were as simple as "white means it cannot be modified (pass by value, const reference, etc.) and yellow means it can (non-const reference, pointer, etc.)"

I wonder if this exists?