[libcxx-commits] [libcxx] [libc++] Simplify the implementation of string::{append, assign, assign_range} (PR #162254)

[Louis Dionne via libcxx-commits]

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@@ -698,6 +698,8 @@ __concatenate_strings(const _Allocator& __alloc,
                       __type_identity_t<basic_string_view<_CharT, _Traits> > __str1,
                       __type_identity_t<basic_string_view<_CharT, _Traits> > __str2);
 
+// This is true if we know for a fact that dereferencing the iterator won't access any part of the `string` we're
+// modifying if __addr_in_range(*it) returns false.
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ldionne wrote:

The purpose of `__string_is_trivial_iterator`, as far as I remember and looking at https://reviews.llvm.org/D98573, is to identify iterators that basically don't throw in their operations (e.g. `operator++`). I don't know whether it still makes sense to check that or whether we can do better in our implementation to accommodate such iterators, but I think that we should document its purpose in a historically accurate way.

https://github.com/llvm/llvm-project/pull/162254