[PATCH] D45405: [clang-tidy] [modernize-use-auto] Add a threshold for minimal type name length to be replaced with 'auto'

[Alexander Kornienko via Phabricator via cfe-commits]

alexfh added inline comments.


================
Comment at: clang-tidy/modernize/UseAutoCheck.cpp:290
+    : ClangTidyCheck(Name, Context), RemoveStars(Options.get("RemoveStars", 0)),
+      MinTypeNameLength(Options.get("MinTypeNameLength", 0)) {}
 
----------------
zinovy.nis wrote:
> alexfh wrote:
> > alexfh wrote:
> > > lebedev.ri wrote:
> > > > zinovy.nis wrote:
> > > > > lebedev.ri wrote:
> > > > > > alexfh wrote:
> > > > > > > Maybe make the default 5? Or does anyone really want to replace `int/long/char/bool/...` with `auto`?
> > > > > > That might be a bit surprising behavioral change..
> > > > > > At least it should be spelled out in the release notes.
> > > > > > (my 5 cent: defaulting to 0 would be best)
> > > > > Maybe we can somehow mention the current option value in a warning message?
> > > > Sure, can be done, but that will only be seen when it does fire, not when it suddenly stops firing...
> > > > Maybe we can somehow mention the current option value in a warning message?
> > > 
> > > We don't do that for options of other checks (and for the other option here). I don't think this case is substantially different.
> > > That might be a bit surprising behavioral change..
> > 
> > For many it will be a welcome change ;)
> > 
> > > At least it should be spelled out in the release notes.
> > 
> > No objections here.
> > 
> > > (my 5 cent: defaulting to 0 would be best)
> > 
> > You see it, 5 is a better default, otherwise you'd say "0 cent" ;)
> > 
> > On a serious note, the style guides I'm more or less familiar with recommend the use of `auto` for "long/cluttery type names" [1], "if and only if it makes the code more readable or easier to maintain" [2], or to "save writing a longish, hard-to-remember type that the compiler already knows but a programmer could get wrong" [3]. None of these guidelines seem to endorse the use of `auto` instead of `int`, `bool` or the like.
> > 
> > From my perspective, the default value of 5 would cover a larger fraction of real-world use cases.
> > 
> > [1] https://google.github.io/styleguide/cppguide.html#auto
> > [2] http://llvm.org/docs/CodingStandards.html#use-auto-type-deduction-to-make-code-more-readable
> > [3] https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#es11-use-auto-to-avoid-redundant-repetition-of-type-names
> Or even 7 to ignore 'double' too.
I'd go with 5, which is super-easy to explain: it's the smallest value that will always lead to shorter code. 7 doesn't have this advantage.


https://reviews.llvm.org/D45405