[libcxx-commits] [PATCH] D101003: [libc++] <span>, like <string_view>, has no use for debug iterators.

[Arthur O'Dwyer via Phabricator via libcxx-commits]

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  A span has no idea what container (if any) "owns" its iterators, nor
  under what circumstances they might become invalidated.
  
  This fixes the following libcxx tests under `-D_LIBCPP_DEBUG=1`:
  - libcxx/test/std/containers/views/span.cons/deduct.pass.cpp
  - libcxx/test/std/containers/views/span.iterators/begin.pass.cpp
  - libcxx/test/std/containers/views/span.iterators/end.pass.cpp
  - libcxx/test/std/containers/views/span.iterators/rbegin.pass.cpp
  - libcxx/test/std/containers/views/span.iterators/rend.pass.cpp
  - libcxx/test/std/containers/views/span.sub/first.pass.cpp
  - libcxx/test/std/containers/views/span.sub/last.pass.cpp
  - libcxx/test/std/containers/views/span.sub/subspan.pass.cpp

It does occur to me that we could probably come up with a strategy for `string_view` and `span` to do debug iterators, where you could form an association of a `string_view` object with a `C` object, and the `string_view`'s iterators would be sort of "transitively" associated with that `C`; and this association would be formed whenever you (1) converted a `string` directly to a `string_view` or (2) constructed a `string_view` from a pair of `C::iterator` (for `C`=`string` or `vector`). //However//, this idea is clearly beyond the scope of this PR, and I'm not aware that anyone is asking for it to exist, either.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D101003

Files:
  libcxx/include/span


Index: libcxx/include/span
===================================================================
--- libcxx/include/span
+++ libcxx/include/span
@@ -200,7 +200,7 @@
     using const_pointer          = const _Tp *;
     using reference              = _Tp &;
     using const_reference        = const _Tp &;
-    using iterator               =  __wrap_iter<pointer>;
+    using iterator               = pointer;
     using reverse_iterator       = _VSTD::reverse_iterator<iterator>;
 
     static constexpr size_type extent = _Extent;
@@ -375,7 +375,7 @@
     using const_pointer          = const _Tp *;
     using reference              = _Tp &;
     using const_reference        = const _Tp &;
-    using iterator               =  __wrap_iter<pointer>;
+    using iterator               = pointer;
     using reverse_iterator       = _VSTD::reverse_iterator<iterator>;
 
     static constexpr size_type extent = dynamic_extent;


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