The async refactorings ignore whether a completion handler had
`@escaping` or not. In preparation of fixing this, fix up all functions
to have `@escaping` for their completion handler parameter.
Also some small miscellaneous fixes in order to reduce the number of
warnings output on test failures and also the addition of `REQUIRES:
concurrency` on all tests.
Previously we would drop comments between nodes in
a BraceStmt, as we printed each node out individually.
To remedy this, always make sure we scan backwards
to find any preceding comments attached to a node,
and also keep track of any SourceLocs which we
don't print, but may have comments attached which
we want to preserve.
rdar://77401810
When converting a call or function, rename declarations such that
redeclaration errors and shadowing are avoided. In some cases this will
be overly conservative, but since any renamed variable can be fixed with
edit all in scope, this is preferred over causing redeclaration errors
or possible shadowing.
Resolves rdar://73973517
If we're lifting them outside of the control flow
structure they're dealing with, turn them into
placeholders, as they will no longer perform the
control flow the user is expecting.
This handles:
- Return statements at the top-level of the callback.
- Break statements in switches that we re-write.
Resolves rdar://74014897.
Remove an optional chain of a success parameter,
as it will no longer be optional, similar to how
we remove a force unwrap.
Note that while this is a locally valid transform
within the optional chain, e.g `foo?.x` -> `foo.x`,
it may change the type of the overall chain, which
could cause errors elsewhere in the code. However
this is generally more useful to the user than
just leaving `foo` as a placeholder. Note this is
only the case when no other optionals are involved
in the chain, e.g `foo?.x?.y` -> `foo.x?.y` is
completely valid.
Resolves rdar://74014826.
Adds three refactorings intended to help users migrate their existing
code to use the new async language features:
1. Convert call to use async alternative
2. Convert function to async
3. Add async alternative function
A function is considered to have an async alternative if it has a void
return type and has a void returning closure as its last parameter. A
method to explicitly mark functions as having an async alternative may
be added to make this more accurate in the future (required for eg.
a warning about a call to the non-async version of a function in an
async context).
(1) converts a call to use the new `await` async language syntax. If the
async alternative throws, it will also add `try`. The closure itself is
hoisted out of the call, see the comments on
`AsyncConversionStringBuilder` for specifics.
(2) converts a whole function to `async`, using (1) to convert any calls
in the function to their async alternatives. (3) is similar to (2), but
instead *adds* a function and replaces calls to its
completion/handler/callback closure parameter with `return` or `throws`.
Resolves rdar://68254700
