Shadowing a class member: wrong?

Obviously, it has to be on a project scale instead of an individual scale; it doesn't help if you never make a mistake based on a variable shadowing, if it's not common in a particular project and other people make mistakes because of that code.

In general, it's probably best to either always use "this->" or never use it (and never shadow members) within a given codebase. Either way works, but any mixture leads to patches which can't be reviewed easily (that is, you can't tell from the function header and 3 lines of context whether a patch is right).