fix(cpp): a range-based for loop over auto elements has the element type of its range

CHANGELOG.md

@@ -86,9 +86,10 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - In C++, a class, struct or method now keeps the namespaces and the class it is declared in when the parser misreads something earlier in the file, such as an unknown macro in front of a member or in a class header. Before, everything after the misread code could lose them, or land inside a class it isn't in: in protocolbuffers/protobuf, `FieldDescriptor` was indexed without `google::protobuf::`, and in RocksDB, the `Opts` struct declared inside a cache table class was indexed outside it, so finding a class's base classes and the methods called on its objects fell back to guessing by name. Methods that had come loose from their class are its members again, and classes the misread code had hidden, like leveldb's POSIX file and environment classes, are now indexed. Re-index C++ projects after upgrading.
 - In C++, a call on a variable, parameter or member declared as a standard-library or other outside type with a lowercase name, like `std::string`, `std::vector`, `std::set` or `absl::flat_hash_set`, no longer links to a project method that only shares the method's name. In google/leveldb, `saved_key_.clear()` on a `std::string saved_key_;` reached `Slice::clear`, and in protocolbuffers/protobuf, `proto.append(…)` on a `std::string` reached an unrelated `LeftoverBuffer::append`. The same goes for `->` through a raw pointer like `std::string* out`, while `->` through a smart pointer, iterator or optional still links to the type it holds. Comments also no longer pass for a variable's declaration, so more calls now link to the method of the type the variable is really declared with. Re-index C++ projects after upgrading.
 - In C++, a class written with attribute macros the parser can't read now keeps its members. That covers several macros between `class` and the class name, like protocolbuffers/protobuf's generated `class PROTOBUF_EXPORT PROTOBUF_FUTURE_ADD_EARLY_WARN_UNUSED Any final`, a macro with arguments there, like RocksDB's `struct ALIGN_AS(64U) HandleImpl`, or one before a template specialization, and macros on a member: in front of it (`PROTOBUF_FUTURE_ADD_EARLY_NODISCARD`), between a pointer and its name (`PROTOBUF_NONNULL`), after its parameters or its name (`ABSL_ATTRIBUTE_LIFETIME_BOUND`, google/leveldb's `LOCKS_EXCLUDED(mu_)` and `GUARDED_BY(mu_)`), or alone on a line above a comment ({fmt}'s `FMT_BEGIN_EXPORT`). Before, protobuf's generated message classes were missing and their members, like `GetDescriptor`, `GetReflection` and `unknown_fields`, were indexed as functions outside any class, and leveldb's annotated methods were indexed under the annotation's name, so calls to them linked to nothing. Re-index C++ projects after upgrading.
-- In C++, a call on a range-based `for` loop's variable, like `suite->SetVerbose(verbose)` inside `for (ConformanceTestSuite *suite : suites)`, now links to the method of the type the loop declares. Before, the loop's declaration was never read, so the call was matched by the variable's name alone: in RocksDB, `log->file()` on a `log::Writer` went to `BlobLogWriter::file`, and a loop variable named like a member of its class was taken for that member. The variable counts only inside its loop, and loops over `auto` elements resolve as before. Re-index C++ projects after upgrading.
+- In C++, a call on a range-based `for` loop's variable, like `suite->SetVerbose(verbose)` inside `for (ConformanceTestSuite *suite : suites)`, now links to the method of the type the loop declares. Before, the loop's declaration was never read, so the call was matched by the variable's name alone: in RocksDB, `log->file()` on a `log::Writer` went to `BlobLogWriter::file`, and a loop variable named like a member of its class was taken for that member. The variable counts only inside its loop. Re-index C++ projects after upgrading.
 - In C++, a call made with `->` on a variable, parameter or member declared as a `std::unique_ptr`, `std::shared_ptr` or `std::optional`, like `iter->Valid()` on a `std::unique_ptr<Iterator> iter`, now links to that method of the type it holds, or of a class that type inherits from, with the type looked up the way C++ does it, so a class of the same name nested elsewhere is not mistaken for it. Before, the call went to whichever project method shared its name: in facebook/rocksdb, `iter->Valid()` reached `ArenaWrappedDBIter::Valid` and `fs->GetFileSize(…)` on a `std::shared_ptr<FileSystem>` reached a test's stand-in file system, and calls like `it->Next()` were often not linked at all. When what it holds is a template parameter or a standard-library type, like `std::unique_ptr<std::deque<…>>`, the call no longer links to a project method. Re-index C++ projects after upgrading.
 - In C++, a call a method makes with no receiver, or through `this->`, now links to the method C++ itself would call: one of the method's own class, else one the class inherits from a base class, else one of a class it is nested in. The same goes for a call in a lambda inside the method, and of a class's overloads the one the call's arguments fit is taken. Before, the call was matched by its name alone, so another class's method of that name could win because it was declared nearer or found first: in protocolbuffers/protobuf, every generated message's `Swap` and move assignment calling `InternalSwap(…)` reached `Any::InternalSwap`, and the `GetArena()` messages inherit from `MessageLite` reached an arena helper's `GetArena`, while googletest's `~linked_ptr() { depart(); }`, vendored in facebook/rocksdb, reached `linked_ptr_internal::depart`. Calls C++ doesn't look up in the class are matched as before: a free function's, a call to a parameter or local of that name, and a template's bare call into a base class that depends on its template parameters. Re-index C++ projects after upgrading. Thanks @danusha2345 for reporting the C++ case in #1952.
+- In C++, a call on the variable of a range-based `for` loop over `auto` elements, like `cfd->Ref()` inside facebook/rocksdb's `for (auto cfd : cfds)`, now links to the method of the type the loop goes over. That type is read from what the loop iterates: a `std::vector`, `std::set`, `absl::Span` or similar container, protocolbuffers/protobuf's `RepeatedPtrField` or RocksDB's `autovector`, whether a variable, parameter or member holds it, an `auto` variable is set to it or a function or method returns it, and a project class you loop over through its `begin()`, like RocksDB's `ColumnFamilySet`. Before, the call was matched by the variable's name, or by an earlier variable of that name: in RocksDB, `blob_file.GetBlobFileNumber()` over a list of `BlobFileGarbage` reached `BlobFileAddition::GetBlobFileNumber`, and in protobuf's Objective-C generator, calls over a list of `std::unique_ptr<MessageGenerator>` reached other generators' methods. A call on an element of a standard-library type, like `file.find(…)` over a `std::vector<std::string>`, no longer links to a project method, and `->` on an element held in a `std::unique_ptr` or `std::shared_ptr` reaches the type it holds. Re-index C++ projects after upgrading.
 - Framework support now switches on when an app's `package.json` sits three or more folders deep, as with an ASP.NET solution's Angular or React app in `src/Web/ClientApp/`, or a React app in a workspace folder like `web/ui/mantine-ui/`. Before, only the project root and the first two folder levels were read, so frameworks such as Angular, React Router, Vue Router, SvelteKit and TanStack Router could go undetected there: an Angular app's routes, its `routerLink` and `router.navigate(…)` navigation and its template's event bindings were missing, so a handler used only from a `(click)` binding had no callers, and a React app's `navigate('/login')` calls didn't reach their route. Re-index projects laid out this way after upgrading.
 - In a repository that mixes languages, a web framework's naming conventions now link only code written in that framework's own languages. Before, Express's also linked Go and Python code: in etcd a Go method's `*zap.Logger` result type linked to the method itself, and in Harbor a Python `self.jaeger.validate()` call linked to another class's `validate`. Links that cross languages on purpose, like React Native and Expo native modules, Swift and Objective-C, Drupal's `routing.yml`, SvelteKit's `$lib/…` imports in `.ts` files and a Razor page's `@model`, are unchanged.
 - In C and C++, a call written from the global scope, like `::leveldb::RepairDB(…)` or `::hpb::CreateMessage(…)`, now links to the function of exactly that name, and one through a namespace alias, like protobuf's `::_pbi::…` calls, to the function in the aliased namespace. Before, these calls were dropped unless the repository also held Swift and Objective-C files, and even then a name spelled out in full, like `::google::protobuf::internal::TSanWrite(…)`, linked to nothing, while `::operator delete(…)` linked to one class's own `operator delete`. A global call never links to a function or method of the same name inside a namespace or class, such as a wrapper `open()` that calls the C library's `::open(…)`, and `::std::…` and `::testing::…` calls stay unlinked unless that library's source is part of your project. Re-index C and C++ projects after upgrading.