In the general case, this is done by reverse engineering the "best"
places for requirements to go from the requirement signature.
Conformance/superclass requirements like Self: Foo and Self.T: Bar defer
to the inheritance clause if they appear there, or are attached to the
protocol where clause or T (respectively) if not. A conformance
requirement like Self.T.U: Baz will go on T (if T is declared in the
protocol being printed).
Same-type requirements always go in where clauses, and specifically a
where clause of an associated type that is mentioned in them, so
something simple like Self.T.U == Int goes on the T associated type
definition, and similarly Self.T.U == Self.V will go on V (it's kinda
nonsense, but also more directly connected to V). There's a left-bias
for cases without an "obvious" choice, meaning something more
complicated like Self.T.U == Foo<Self.V> will end up on T.
Requirements that don't fit elsewhere will go on the
protocol (e.g. Self.AssocTypeFromSuperProtocol == Int).
Textual SIL containing something like: `infix static func ==(a: T, b: T) -> Bool` cannot be parsed and results in an error like:
```
error: 'infix' modifier is not required or allowed on func declarations
```
Interestingly enough, `prefix` and `postfix` attributes do not result in the same kind of errors.
Introduce an algorithm to canonicalize and minimize same-type
constraints. The algorithm itself computes the equivalence classes
that would exist if all explicitly-provided same-type constraints are
ignored, and then forms a minimal, canonical set of explicit same-type
constraints to reform the actual equivalence class known to the type
checker. This should eliminate a number of problems we've seen with
inconsistently-chosen same-type constraints affecting
canonicalization.
When enumerating requirements, always use the archetype anchors to
express requirements. Unlike "representatives", which are simply there
to maintain the union-find data structure used to track equivalence
classes of potential archetypes, archetype anchors are the
ABI-stable canonical types within a fully-formed generic signature.
The test case churn comes from two places. First, while
representatives are *often* the same as the archetype anchors, they
aren't *always* the same. Where they differ, we'll see a change in
both the printed generic signature and, therefore, it's
mangling.
Additionally, requirement inference now takes much greater
care to make sure that the first types in the requirement follow
archetype anchor ordering, so actual conformance requirements occur in
the requirement list at the archetype anchor---not at the first type
that is equivalent to the anchor---which permits the simplification in
IRGen's emission of polymorphic arguments.
There was a ton of complicated logic here to work around
two problems:
- Same-type constraints were not represented properly in
RequirementReprs, requiring us to store them in strong form
and parse them out when printing type interfaces.
- The TypeBase::getAllGenericArgs() method did not do the
right thing for members of protocols and protocol extensions,
and so instead of simple calls to Type::subst(), we had
an elaborate 'ArchetypeTransformer' abstraction repeated
in two places.
Rewrite this code to use GenericSignatures and
GenericFunctionType instead of old-school GenericParamLists
and PolymorphicFunctionType.
This changes the code completion and AST printer output
slightly. A few of the changes are actually fixes for cases
where the old code didn't handle substitutions properly.
A few others are subjective, for example a generic parameter
list of the form <T : Proto> now prints as <T where T : Proto>.
We can add heuristics to make the output whatever we want
here; the important thing is that now we're using modern
abstractions.
We have a special case check for the no-escape-by-default rules for a
computed property setter's newValue argument, which if a closure,
obviously has to be escaping. But, we checked this by checking the
type's overall DeclContext, which unfortunately meant we also made
nested closures escaping implicitly. This fixes that to only tack on
the implicit escaping at the top level for the setter's type.
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.
- Make sure VarDecls have an associated TypeLoc, like ParamDecls do, then use it for printing the VarDecl's type.
This is done by moving ParamDecl's TypeLoc up to the VarDecl.
This is useful for being able to display the parameter names of function types embedded in VarDecls.
- Use the result TypeLoc of functions for printing. This enables printing parameter names of function types embedded in return types.
- Make sure to annotate attributes while they are printed.
Member operators should be placed within a nominal type (or extension
thereof) that they operate on. Aside from being good style, enforcing
this in the type checker can help with dependency tracking. Addresses
rdar://problem/27536066.
This flips the switch to have @noescape be the default semantics for
function types in argument positions, for everything except property
setters. Property setters are naturally escaping, so they keep their
escaping-by-default behavior.
Adds contentual printing, and updates the test cases.
There is some further (non-source-breaking) work to be done for
SE-0103:
- We need the withoutActuallyEscaping function
- Improve diagnostics and QoI to at least @noescape's standards
- Deprecate / drop @noescape, right now we allow it
- Update internal code completion printing to be contextual
- Add more tests to explore tricky corner cases
- Small regressions in fixits in attr/attr_availability.swift
What I've implemented here deviates from the current proposal text
in the following ways:
- I had to introduce a FunctionArrowPrecedence to capture the parsing
of -> in expression contexts.
- I found it convenient to continue to model the assignment property
explicitly.
- The comparison and casting operators have historically been
non-associative; I have chosen to preserve that, since I don't
think this proposal intended to change it.
- This uses the precedence group names and higherThan/lowerThan
as agreed in discussion.
and provide a fix-it to move it to the new location as referenced
in SE-0081.
Fix up a few stray places in the standard library that is still using
the old syntax.
Update any ./test files that aren't expecting the new warning/fix-it
in -verify mode.
While investigating what I thought was a new crash due to this new
diagnostic, I discovered two sources of quite a few compiler crashers
related to unterminated generic parameter lists, where the right
angle bracket source location was getting unconditionally set to
the current token, even though it wasn't actually a '>'.
Rather than synthesizing a global operator '==' for Equatable enums,
synthesize a member operator, which is more idiomatic and much
cleaner.
To make sure that these synthesized operators can actually be found,
start considering operator requirements in protocols
more generally in the type checker, so that, e.g., "myEnum == myEnum"
will type-check against Equatable.== and, on successful type-check,
will call the (newly-synthesized) witness for '=='. This both makes it
easier to make sure we find the operators in, e.g., complex multi-file
and lazy-type checking scenarios, and is a step toward the
type-checking improvements described in SE-0091.
- All parts of the compiler now use ‘P1 & P2’ syntax
- The demangler and AST printer wrap the composition in parens if it is
in a metatype lookup
- IRGen mangles compositions differently
- “protocol<>” is now “swift.Any”
- “protocol<_TP1P,_TP1Q>” is now “_TP1P&_TP1Q”
- Tests cases are updated and added to test the new syntax and mangling
This commit defines the ‘Any’ keyword, implements parsing for composing
types with an infix ‘&’, and provides a fixit to convert ‘protocol<>’
- Updated tests & stdlib for new composition syntax
- Provide errors when compositions used in inheritance.
Any is treated as a contextual keyword. The name ‘Any’
is used emit the empty composition type. We have to
stop user declaring top level types spelled ‘Any’ too.
Allow 'static' (or, in classes, final 'class') operators to be
declared within types and extensions thereof. Within protocols,
require operators to be marked 'static'. Use a warning with a Fix-It
to stage this in, so we don't break the world's code.
Protocol conformance checking already seems to work, so add some tests
for that. Update a pile of tests and the standard library to include
the required 'static' keywords.
There is an amusing name-mangling change here. Global operators were
getting marked as 'static' (for silly reasons), so their mangled names
had the 'Z' modifier for static methods, even though this doesn't make
sense. Now, operators within types and extensions need to be 'static'
as written.
Try to match the original spelling of static/class in diagnostics and
when printing the AST. Also fixes cases with
PrintOptions.PrintImplicitAttrs = false, where we would just print
'class', which was not valid code.
Start threading all keyword (and contextual keyword) printing through
printName, and add a new PrintNameContext for keywords. For now we just
pass this through without changing behaviour.
Also add an operator<< for printing from the tok:: kind for keywords,
which makes it much more convenient for performing the required
callbacks.
rdar://problem/24292226
We already know to print one before printing the body brace (if we're
printing function bodies), and it certainly doesn't belong in the
*name* portion of the decl.
Also add a cursor info test with a deinit.
