This disables TBD validation when C++ interop is enabled, unless an explicit `-validate-tbd-against-ir=` flag was passed.
rdar://83405989 / https://github.com/apple/swift/issues/56458
C++ iterator types are often templated, and sometimes declare `operator==` as a non-member templated function. In libc++, an example of this is `__wrap_iter` which is used as an iterator type for `std::vector` and `std::string`.
We don't currently import templated non-member operators into Swift, however, we still want to support common C++ iterator patterns.
This change adds logic to instantiate templated non-member `operator==` for types that define `iterator_category` and are therefore likely to be valid iterator types.
rdar://97915515
Using std::vector in a for-loop causes problems with some configurations. See rdar://87728422 and rdar://87805795.
This is a temporary fix to make the bots green.
Adds tests for using std-vector and some other interesting types.
This patch fixes four mis conceptions that the compiler was previously making:
1. Implicit destructors have no side effects. (Yes, this means we were not cleaning up some objects.)
2. Implicit destructors have bodies. (Technically they do, but the body doesn't include CallExprs that they make when lowered to IR.)
3. Functions other than methods can be uninstantiated templates.
4. Uninstantiated templates may have executable code. (I.e., we can never take the fast path.)
And makes sure that we visit the destructor of any VarDecl (including parameters).
