The Swift 4 Migrator is invoked through either the driver and frontend
with the -update-code flag.
The basic pipeline in the frontend is:
- Perform some list of syntactic fixes (there are currently none).
- Perform N rounds of sema fix-its on the primary input file, currently
set to 7 based on prior migrator seasons. Right now, this is just set
to take any fix-it suggested by the compiler.
- Emit a replacement map file, a JSON file describing replacements to a
file that Xcode knows how to understand.
Currently, the Migrator maintains a history of migration states along
the way for debugging purposes.
- Add -emit-remap frontend option
This will indicate the EmitRemap frontend action.
- Don't fork to a separte swift-update binary.
This is going to be a mode of the compiler, invoked by the same flags.
- Add -disable-migrator-fixits option
Useful for debugging, this skips the phase in the Migrator that
automatically applies fix-its suggested by the compiler.
- Add -emit-migrated-file-path option
This is used for testing/debugging scenarios. This takes the final
migration state's output text and writes it to the file specified
by this option.
- Add -dump-migration-states-dir
This dumps all of the migration states encountered during a migration
run for a file to the given directory. For example, the compiler
fix-it migration pass dumps the input file, the output file, and the
remap file between the two.
State output has the following naming convention:
${Index}-${MigrationPassName}-${What}.${extension}, such as:
1-FixitMigrationState-Input.swift
rdar://problem/30926261
1. Make sure the actions taken by fixits are reflected in diagnostics messages.
2. Issue missing cases diagnostics at the start of the switch statement instead of its end.
3. Use <#code#> instead of <#Code#> in the stub.
This commit adds a fix-it to remove @discardableResult on functions that return Void or Never. The fix-it is at the warning level. A test was added to verify that the fix-it removes the @discardableResult. This issue was reported in SR-3359:
https://bugs.swift.org/browse/SR-3359
Changes:
TypeCheckAttr.cpp: implemented AttributeChecker::visitDiscardableResultAttr to add a fix-it to remove @discardableResult on functions returning Void or Never.
DiagnosticsSema.def: Added a warning with a diagnostic message.
LoggingWrappers.swift.gyb, HashedCollections.swift.gyb: Removed @discardableResult on functions returning Void.
fixits-apply-all.swift, fixits-apply-all.swift.result: Added tests to verify that @discardableResult is removed from functions returning Void or Never.
Previously, bridging conversions were handled as a form of "explicit
conversion" that was treated along the same path as normal
conversions in matchTypes(). Historically, this made some
sense---bridging was just another form of conversion---however, Swift
now separates out bridging into a different kind of conversion that is
available only via an explicit "as". This change accomplishes a few
things:
* Improves type inference around "as" coercions. We were incorrectly
inferring type variables of the "x" in "x as T" in cases where a
bridging conversion was expected, which cause some type inference
failures (e.g., the SR-3319 regression).
* Detangles checking for bridging conversions from other conversions,
so it's easier to isolate when we're applying a bridging
conversion.
* Explicitly handle optionals when dealing with bridging conversions,
addressing a number of problems with incorrect diagnostics, e.g.,
complains about "unrelated type" cast failures that would succeed at
runtime.
Addresses rdar://problem/29496775 / SR-3319 / SR-2365.
We could probably make this even more general, but this specifically
avoids trying to insert an "as AnyObject" fix-it, which will now work
but probably produce an incorrect result. This comes up when working
with swift_newtype wrappers of CF types being passed to CFTypeRef
parameters.
rdar://problem/26678862
Slava pointed out that we have an existing version of the code from
the previous commit that's only used when checking types. Replace it
with the new code, which handles more cases.
* [Parser] Correct a fixit to preserve the trailing content after replacing Protocol<A, B>. rdar://27992964
When migrating, we found our fixit to replace the old protocol composition syntax, namely "Protocol<A, B>",
to the new syntax, "A & B", does not preserve the trailing content after '>'. For instance, we replace "Protocol<A, B>?"
with "A & B". This patch fixes the issue by inserting whatever after '>' in the old syntax to the new
replacement string. I consider this as a hack; the root-cause fix should be in the lexer to smartly separate
'>' and '?' as two tokens instead of one.
* [test] Update existing test.
* [FixCode] Add diagnosis/fixit to help users deal with BooleanType's removal.
Due to migration reasons, types used to conform to BooleanType, which
must contain a member var 'boolValue', now does not convert to Bool. This patch
adds a specific diagnosis/fixit to explicitly invoke 'boolValue' to please the
context types.
* Address Jordan's code review comments.
We saw manual migration is necessary on these cases to add 'as Type'. This patch starts
to issue compiler fixits on return statement and initialization just like in other type-mismatch
cases.
And improve the error message for non-empty braces; if we're going to
ignore the contents, we should at least point you in the right
direction for Swift 3.
rdar://problem/27576922
This fixes several issues:
- By default parent types of alias types are not printed which results in
- Erroneous fixits, for example when casting to 'Notification.Name' from a string, which ends up adding erroneous cast
as "Name(rawValue: ...)"
- Hard to understand types in code-completion results and diagnostics
- When printing with 'fully-qualified' option typealias types are printed erroneously like this "<PARENT>.Type.<TYPEALIAS>"
The change make typealias printing same as nominal types and addresses the above.
This fixit comes from a note, but is very useful for migration of code
that has changed from AnyObject to Any but wants to do AnyObject
dispatch.
rdar://problem/27793389
We added the fixit to help users manually migrate enum case references after the declaration
has been renamed; however, when interacting with the migrator, the fixit may revert migrator's
correct changes, when the migrator updates references before updating the declaration. This patch
blacklists the fixit in migrator's pass, so we leave it to users' manually application if necessary.
