[clang-tidy] new check: modernize-deprecated-iterator-base

[nick]

Summary

Finds deprecated in C++17 inheritance from std::iterator and replaces it with type aliases. The check itself is not marked as C++17 because it could be applied to any project with no harm.

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Because of need to catch CXXBaseSpecifier I extended clang::ast_type_traits, but locally and in a hacky way. I would be glad if someone who knows ASTMatcher internals do add a proper CXXBaseSpecifier support.

[Eugene.Zelenko]

clang-tools-extra/clang-tidy/modernize/DeprecatedIteratorBaseCheck.cpp

94

Please don't use auto when type is not spelled in same statement or iterator.

101

Please don't use auto when type is not spelled in same statement or iterator.

116

Please don't use auto when type is not spelled in same statement or iterator.

130

Please don't use auto when type is not spelled in same statement or iterator.

219

Should it check for C++17 or newer?

254

Please don't use auto when type is not spelled in same statement or iterator.

260

Please don't use auto when type is not spelled in same statement or iterator.

281

Please don't use auto when type is not spelled in same statement or iterator.

clang-tools-extra/docs/ReleaseNotes.rst

139

Please put in new checks list in alphabetical order.

[nick]

Addressed comments.

[nick]

clang-tools-extra/clang-tidy/modernize/DeprecatedIteratorBaseCheck.cpp

219

I do not think so. It is a backward compatible change. The standard never required to inherit iterators from the std::iterator, and the standard library itself had not inheriting from std::iterator iterators.

[njames93]

First of all I'd definitely wait until a patch to include ASTMatcher support for CXXBaseSpecifier lands before progressing with this.
Secondly this issue should be warned on by clang when compiling with c++17 with some stdlib support, libc++ should mark iterator as deprecated when compiling with c++17.
Having said that this still has value as the fix its are helpful.