however the traces are not merged on `await` or async function calls
yet.
When an async function has an error set or error union as its return
type, it has a `StackTrace` before the args in the frame, so that it is
accessible from `anyframe->T` awaiters. However when it does not have an
errorable return type, but it does call or await an errorable, it has a
stack trace just before the locals. This way when doing an `@asyncCall`
on an async function pointer, it can populate the args (which are after
the `StackTrace`) because it knows the offset of the args based only on
the return type.
This sort of matches normal functions, where a stack trace pointer could
be supplied by a parameter, or it could be supplied by the stack of the
function, depending on whether the function itself is errorable.
* add implicit cast from `*@Frame(func)` to `anyframe->T` or `anyframe`.
* add implicit cast from `anyframe->T` to `anyframe`.
* `resume` works on `anyframe->T` and `anyframe` types.
It used to be that usingnamespace was only allowed at top level. This
made it OK to put the state inside the AST node data structure. However,
now usingnamespace can occur inside any aggregate data structure, and
therefore the state must be in the TopLevelDeclaration rather than in
the AST node.
There were two other problems with the usingnamespace implementation:
* It was passing the wrong destination ScopeDecl, so it could cause an
incorrect error such as "import of file outside package path".
* When doing `usingnamespace` on a file that already had
`pub usingnamespace` in it would "steal" the usingnamespace, causing
incorrect "use of undeclared identifier" errors in the target file.
closes#2632closes#2580
