This is a corner case but would previously lead to a compiler crash
or miscompile.
Fixes <rdar://problem/21991470>, <https://bugs.swift.org/browse/SR-5022>.
Conditional conformances aren't quite ready yet for Swift 4.1, so
introduce the flag `-enable-experimental-conditional-conformances` to
enable conditional conformaces, and an error when one declares a
conditional conformance without specifying the flag.
Add this flag when building the standard library (which will vend
conditional conformances) and to all of the tests that need it.
Fixes rdar://problem/35728337.
When a particular nominal type or extension thereof declares conformance
to a protocol, check whether that type or extension contains any members
that *nearly* match a defaulted requirement (i.e., a requirement that
is satisfied by something in a protocol extension), but didn’t match
for some reason and weren’t used to satisfy any other requirement of
that protocol. It’s intended to catch subtle mistakes where a default
gets picked instead of the intended member.
This is a generalization of the code we’ve had for @objc optional
requirements for a long time.
Fixes rdar://problem/24714887.
Some messages said 'typealias' and others said 'type alias'.
Change everything to use 'type alias' consistently (except
when it's talking about the keyword itself).
A protocol extension can add additional generic constraints on
'Self' or associated types thereof. In particular, 'Self' itself
can have a superclass constraint placed on it.
There were a couple of problems with this corner case:
- Type aliases defined in protocols that 'Self' conforms to _as a
concrete type_ to were not handled properly, triggering an assertion.
For example,
protocol P { typealias T = ... }
class C : P {}
protocol Q {}
extension Q where Self : C { ... T ... }
The conformance o P comes from the 'Self : C' constraint.
- If the type was found in a superclass of 'Self', we used the wrong
base type for the substitution.
For example,
protocol P {}
class C<T> { typealias A = T }
class D : C<Int> {}
extension P where Self : D { ... A ... }
The substituted type of 'A' should be computed with a self type
of C<Int> here.
Also, take another stab at cleaning up the mess that is
resolveTypeInContext() and related bits of code.
As we've done with layout requirements, introduce a new entry point
(addTypeRequirement) that handles unresolved type requirements of the
form `T: U`, resolves the types, and then can
1. Diagnose any immediate problems with the types,
2. Delay the type requirement if one of the types cannot be resolved,
or
3. Break it into one or more "direct" requirements.
This allows us to clean up and centralize a bunch of checking that was
scattered/duplicated across the GSB and type checker.
Within an extension, references to other members of the extended type
are permitted without qualification. This is intended to work even
when the extended type was a nested type, although members of the
enclosing type are /not/ visible in this case. In order to implement
this, the type checker pre-checks to see if there are /any/ members
with this name and then rewrites the unqualified reference to a
qualified one, based on an unresolved TypeExpr with the name of the
enclosing type. Unfortunately, if the enclosing type is a nested type,
that isn't going to work very well---we find the correct declaration,
but fail to map it into context by virtue of not realizing where it
came from. Fix this by explicitly checking for this case.
https://bugs.swift.org/browse/SR-3847
Not really specific to typealiases; but we don't allow nominal types
to be nested inside protocols yet, and all other types of protocol
members have witnesses in the concrete type.
Fixes <https://bugs.swift.org/browse/SR-2792>.
First, ensure all ParamDecls that are synthesized from scratch are given
both a contextual type and an interface type.
For ParamDecls written in source, add a new recordParamType() method to
GenericTypeResolver. This calls setType() or setInterfaceType() as
appropriate.
Interestingly enough a handful of diagnostics in the test suite have
improved. I'm not sure why, but I'll take it.
The ParamDecl::createUnboundSelf() method is now only used in the parser,
and no longer sets the type of the self parameter to the unbound generic
type. This was wrong anyway, since the type was always being overwritten.
This allows us to remove DeclContext::getSelfTypeOfContext().
Also, ensure that FuncDecl::getBodyResultTypeLoc() always has an interface
type for synthesized declarations, eliminating a mapTypeOutOfContext()
call when computing the function interface type in configureInterfaceType().
Finally, clean up the logic for resolving the DynamicSelfType. We now
get the interface or contextual type of 'Self' via the resolver, instead
of always getting the contextual type and patching it up inside
configureInterfaceType().
In the constraint solver, we've traditionally modeled nested type via
a "type member" constraint of the form
$T1 = $T0.NameOfTypeMember
and treated $T1 as a type variable. While the solver did generally try
to avoid attempting bindings for $T1 (it would wait until $T0 was
bound, which solves the constraint), on occasion we would get weird
behavior because the solver did try to bind the type
variable.
With this commit, model nested types via DependentMemberType, the same
way we handle (e.g.) the nested type of a generic type parameter. This
solution maintains more information (e.g., we know specifically which
associated type we're referring to), fits in better with the type
system (we know how to deal with dependent members throughout the type
checker, AST, and so on), and is easier to reason able.
This change is a performance optimization for the type checker for a
few reasons. First, it reduces the number of type variables we need to
deal with significantly (we create half as many type variables while
type checking the standard library), and the solver scales poorly with
the number of type variables because it visits all of the
as-yet-unbound type variables at each solving step. Second, it
eliminates a number of redundant by-name lookups in cases where we
already know which associated type we want.
Overall, this change provides a 25% speedup when type-checking the
standard library.
As an extension of SR-2208 apply contextual conversion failure checking
to all of the expressions diagnosed via FailureDiagnosis::visitApplyExpr.
Resolves <rdar://problem/28909024>.
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.
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 '>'.
When issuing the error of "not conforming to a protocol P", we used to only note the first
unresolved witness type. This is inconsistent with the situation when the conformance
fails due to unimplemented functions, which we note all of the unimplemented functions.
This patch fixed this by noting all unresolved witness types.
We fail to emit a diagnostic here, because name lookup is able to find the
associated type, even though we don't build a valid generic signature in
this case.
Some more changes to name lookup to untangle "find members in protocols"
from "find concrete witness" flags are needed. I'll do this soon, as part
of fixing unqualified lookup of protocol typealiases, which currently
doesn't work either.
Consider this code:
struct A<T> {
struct B {}
struct C<U> {}
}
Previously:
- getDeclaredType() of 'A.B' would give 'A<T>.B'
- getDeclaredTypeInContext() of 'A.B' would give 'A<T>.B'
- getDeclaredType() of 'A.C' would give 'A<T>.C'
- getDeclaredTypeInContext() of 'A.C' would give 'A<T>.C<U>'
This was causing problems for nested generics. Now, with this change,
- getDeclaredType() of 'A.B' gives 'A.B' (*)
- getDeclaredTypeInContext() of 'A.B' gives 'A<T>.B'
- getDeclaredType() of 'A.C' gives 'A.C' (*)
- getDeclaredTypeInContext() of 'A.C' gives 'A<T>.C<U>'
(Differences marked with (*)).
Also, this change makes these accessors fully lazy. Previously,
only getDeclaredTypeInContext() and getDeclaredIterfaceType()
were lazy, whereas getDeclaredType() was built from validateDecl().
Fix a few spots where the return value wasn't being checked
properly.
These functions return ErrorType if a circularity was detected via
the generic parameter list, or if the extension did not resolve.
They return Type() if the extension cannot be resolved *yet*.
This is pretty subtle, and I'll need to do another pass over
callers of these functions at some point. Many of them should be
moved over to use getSelfInContext(), getSelfOfContext() and
getSelfInterfaceType() instead.
Finally, this patch consolidates logic for diagnosting invalid
nesting of types.
The parser had some code for protocols in bad places and bad things
inside protocols, and Sema had several different bail-outs for
bad things in protocols, nested generic types, and stuff nested
inside protocol extensions.
Combine all of these into a single set of checks in Sema. Note
that we no longer give up early if we find invalid nesting.
Leaving decls unvalidated and un-type-checked only leads to
further problems. Now that all the preliminary crap has been
fixed, we can go ahead and start validating these funny nested
decls, actually fixing some crashers in the process.
Previously, we would only reliably propagate conformances from new extensions to immediate subclasses, since when we visit grandchild classes, we'd see no change in the immediate base class's status. Fix this by walking up the entire superclass chain when we look for new inherited conformances, and track the last processed state of different nominal type decls' extensions separately. Fixes SR-1480.
along with recent policy changes:
- For expression types that are not specifically handled, make sure to
produce a general "unused value" warning, catching a bunch of unused
values in the testsuite.
- For unused operator results, diagnose them as uses of the operator
instead of "calls".
- For calls, mutter the type of the result for greater specificity.
- For initializers, mutter the type of the initialized value.
- Look through OpenExistentialExpr's so we can handle protocol member
references propertly.
- Look through several other expressions so we handle @discardableResult
better.
- Remove stray newline
- Adjust wording when recommending backticks for a keyword identifier
- Provide fix-it when encountering a keyword as an identifier
rdar://problem/25761380
Basic implementatation of SE-0021, naming functions with argument
labels. Handle parsing of compound function names in various
unqualified-identifier productions, updating the AST representation of
various expressions from Identifiers to DeclNames. The result doesn't
capture all of the source locations we want; more on that later.
As part of this, remove the parsing code for the "selector-style"
method names, since we now have a replacement. The feature was never
publicized and doesn't make sense in Swift, so zap it outright.
