Make is_complete static assertion unconditional for unique_ptr<T> bindings.
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This commit adds minimal test infrastructure for inspecting the error messages reported by a C++ compiler when compiling the `.cc` file generated by `cxx_gen::generate_header_and_cc`.
Before this commit, `fn write_unique_ptr_common` in `gen/src/write.rs`
would avoid emitting the following code elements if it the `T` of
`std::unique_ptr<T>` was surely fully defined:
* `static_assert(::rust::is_complete<T>...)`
* `::rust::deleter_if<::rust::detail::is_complete<T>::value>{}(ptr)`
Otherwise, the `static_assert` wasn't emitted, and deletion would be
a simple `ptr->~unique_ptr()` call.
After this commit, the `static_assert`, and the `deleter_if`-guarded
delation are *always* used. This has the following impact:
* This simplifies the code in `gen/src/write.rs`. In particular, it
helps to refactor that code to support arbitrary `T` in
`UniquePtr<T>`, by avoiding the need to calculate `conditional_delete`
for arbirary `T`.
* This may potentially impact performance of C++ compilation runtime.
OTOH:
- The impact seems relatively small in the grand scheme of things.
- The optimization before this commit was based on a heuristic.
For example, the extra code would still be emitted for
`UniquePtr<u32>`.
anforowicz
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Force push above rebases on top of the upstream origin/master - this should make this PR mergeable again. |
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PTAL?
FWIW I tried to leave a justification of small design/coding decisions here and there in code comments + in the description of the last commit.
Similarly to my last PR, this one is also secretly part of a bigger work item (*). I hope that when the bigger work item is done, then
enum UniquePtr,trait ToTypename, andtrait ToMangledcan be removed altogether fromgen/src/write.rs. But even if this doesn't materialize, the changes from this PR under review seem desirable on their own (adding test coverage for C++-side errors + simplifyingfn write_unique_ptr_commonand removing some uses/deconstructions ofUniquePtr).WDYT?
(*) "bigger work item" has evolved from trying to add support for
Vec<[u8; N]>to adding support forVec<T>whereTis not necessarily a simple identifier (e.g. forVec<Vec<T>>). I am still working at this point on the last few remaining places wherewrite.rsorexpand.rsonly work with identifier-only/named types (one of those places isconditional_delete, another isis_maybe_trivial, andfn write_unique_ptr_commonis another one).