[PATCH] D61827: [clang-tidy] modernize-loop-convert: impl const cast iter

[Roman Lebedev via Phabricator via cfe-commits]

lebedev.ri added a comment.

In D61827#1499303 <https://reviews.llvm.org/D61827#1499303>, @torbjoernk wrote:

> In D61827#1499184 <https://reviews.llvm.org/D61827#1499184>, @lebedev.ri wrote:
>
> > In D61827#1499183 <https://reviews.llvm.org/D61827#1499183>, @hintonda wrote:
> >
> > > In D61827#1499160 <https://reviews.llvm.org/D61827#1499160>, @lebedev.ri wrote:
> > >
> > > > This will now trigger on https://godbolt.org/z/9oFMcB right?
> > > >  Just want to point out that this will then have "false-positives" when that loop
> > > >  is an OpenMP for loop, since range-for loop is not available until OpenMP 5.
> > > >
> > > > I don't think this false-positive can be avoided though, if building without
> > > >  `-fopenmp` there won't be anything about OpenMP in AST,
> > > >  and thus no way to detect this case..
> > >
> > >
> > > Could you suggest a simple test case that could be added to the test?  That way, instead of just removing the `if else` block, @torbjoernk could try to handle it.  Or perhaps exclude it from the match altogether.
> >
> >
> > As i said, i don't see how this can be avoided in general.
>
>
> I have to admit that I have very little experience with OpenMP and haven't thought of this at all. Thank you very much for bringing this up.
>
> Would it help to extend the exclusion AST matcher for iterator-based loops by an exclusion for loops with an ancestor of `ompExecutableDirective`?:
>
>   return forStmt(
>                unless(anyOf(isInTemplateInstantiation(),
>                             hasAncestor(ompExecutableDirective()))),
>


Yes and no.
This **will** prevent the false-positive, but **only if** the OpenMP is **enabled** (`-fopenmp`).
If OpenMP is **not enabled**, then that **won't work**, because there won't be anything about OpenMP in AST.
I semi-strongly believe it will be less confusing to only document this false-positive (in check's docs),
instead of trying to prevent it, and reliably failing in half of the cases.


Repository:
  rCTE Clang Tools Extra

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https://reviews.llvm.org/D61827