Re: [boost] Warning policy? local variable hides (i.e. shadows) global variable

On January 15, 2015 8:49:59 AM EST, Andrey Semashev wrote:

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GCC and Clang have had a warning for years (-Wshadow): "Warn whenever a local variable or type declaration shadows another variable, parameter, type, class member (in C++), or instance variable (in Objective-C) or whenever a built-in function is shadowed."

VC++ 2015 (aka 14.0) Preview has now added a similar warning, C4459.

The process of clearing these shadow warnings occasionally finds bugs that are otherwise difficult to detect. Peter Dimov and I have both found bugs in our code in the process of clearing the new C4459 warning. Even though most of the warnings don't actually signify bugs, I'm finding that clearing them makes code clearer and less confusing, particularly code I haven't looked at in a long while.

Should Boost have policy to clear these warnings?

A lot of the warnings involve function argument names. Should we have a guideline to prevent shadow warnings? A convention for argument names would make it easier to submit pull requests. Possible guidelines:

* Prefix function argument names with "a_". Rationale: The "m_"

On Thu, Jan 15, 2015 at 4:11 PM, Beman Dawes wrote: prefix

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for member names has been a success.

Really? I think it's ugly.

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* Suffix function argument names with "_". Rationale: Short and less distracting than "m_" prefix.

I use a _ suffix for data members and a _ prefix for formal parameters.

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Thoughts?

Despite that the warnings should probably be fixed, I don't think there is need for a naming policy.

Normally, I'd dismiss such warnings as unwanted noise, but given Beman's anecdotal evidence of the benefit of addressing them, I'm inclined to agree that they should be addressed.

I'm sure any guideline will contradict someone's habits or preferences, and will be difficult to maintain.

Exactly

As for the particular issue, it's probably better to mangle the global variable names (my preference is "g_") rather than function arguments or local variables. Globals are much more rare and their names should be chosen carefully anyway.

I prefer suffixes for such things, but any convention will work. ___ Rob (Sent from my portable computation engine)