Since retired constraints are re-added back to the circulation in LIFO
order, make sure that all of the constraints are added to the front of
SolverScope::retiredConstraints list.
This leads to some bad recursion through validateDecl(), even
when called from the ITC. We already had machinery to add
implicit constructors later, it just had to be extended to
do it for the superclass as well.
- In functions called from resolveType(), consistently
use a Type() return value to indicate 'unsatisfied
dependency', and ErrorType to indicate failure.
- Plumb the unsatisfiedDependency callback through the
resolution of the arguments of BoundGenericTypes, and
also pass down the options.
- Before doing a conformance check on the argument of a
BoundGenericType, kick off a TypeCheckSuperclass request
if the type in question is a class. This ensures we don't
recurse through NominalTypeDecl::prepareConformanceTable(),
which wants to see a class with a valid superclass.
- The ResolveTypeOfDecl request was assuming that
the request was satisfied after calling validateDecl().
This is not the case when the ITC is invoked from a
recursive call to validateDecl(), hack this up by returning
*true* from isResolveTypeDeclSatisfied(); otherwise we
assert in satisfy(), and we can't make forward progress
in this case anyway.
- Fix a bug in cycle breaking; it seems if we don't invoke
the cycle break callback on all pending requests, we end
up looping forever in an outer call to satisfy().
- Remove unused TR_GlobalTypeAlias option.
Prior to this change, nested generics always reused the archetypes of
either enclosing contexts. For example, given:
struct X<T> {
func f<U>(_: U) { }
}
The generic environment for X.f(_:) would use the same archetype for T
as the generic environment X. This reuse allowed some sloppiness
within the implementation---one did not necessarily have to remember
to substitute entities that came from an immediate outer context---but
caused an annoying limitation that nested generics could not add any
constraints to an archetype that came from an outer scope. Worse, the
compiler would not always diagnose this as an error, leading to
constraints being silently dropped, as in the example from the
referenced radar (see the change to
test/Generics/associated_types.swift).
Now, build a fresh generic environment for each context that
introduces new generic parameters, with archetypes that are completely
separate from the archetypes of enclosing contexts.
Fixes rdar://problem/29207581.
Extensions cannot capture generic parameters from outer contexts.
Their generic parameter list does not point to the outer
parameter list, the signature does not contain outer parameters
and they do not appear in the extension's generic environment.
Furthermore, the depth/index of the extension's parameters may
clash with outer parameters, which would break all kinds of
invariants.
This patch changes these DeclContext methods to return false or
nullptr even if an extension is contained in a generic context:
- isGenericContext()
- getGenericParamsOfContext()
- getGenericSignatureOfContext()
- getGenericEnvironmentOfContext()
The GenericTypeOrArchetypeResolver changes are effectively porting
some existing hacks from the now-dead
PartialGenericTypeOrArchetypeResolver, which dodges some regressions
in the compiler-crashers suite and fixes 11 new crashers. There is
undoubtedly a more principled approach to fix these problems, most of
which now step from recursively looking for a generic environment that
isn't there, but doing so requires improvements to our name lookup.
This makes sure that removed constraints are returned back to the
system after current run, otherwise only constraint graph would
get them back since it has its own scope.
The generic environment of a GenericTypeToArchetypeResolver may be
`nullptr`, as returned by DeclContext::getGenericEnvironmentOfContext,
during prechecking of closure expressions at the necessarily non-generic
top level.
Fixes a couple of crashers.
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().
PotentialArchetype::getNestedType() was effectively reimplementing a
simplified form of mapTypeOutOfContext(), missing some cases in the
process. Just use mapTypeOutOfContext() and resolveArchetype(). While
here, stop re-implementing the addSameType* operations; just call them
directly. With these changes, we no longer need the "typealias in
protocol is too complex" diagnostic.
Eliminates another use of getSelfTypeInContext().
The previous patches regressed a test where we used to diagnose
(poorly) a circular associated type, like so:
associatedtype e: e
With the error "inheritance from non-protocol, non-class type 'e'".
This error went away, because we end up not setting the interface
type of the associated type early enough. Instead, we return an
ErrorType from resolveTypeInContext() and diagnose nothing.
With this patch, emit a diagnostic at the point where the ErrorType
first appears.
Also, remove the isRecursive() bit from AssociatedTypeDecl, and
remove isBeingTypeChecked() which duplicates a bit with the same
name in Decl.
Extending this hack recovers a regression in a previously-fixed
compiler crasher (#26725), and fixes two more compiler crashers. So,
despite it's utter lack of principle, it's progress.
If a sugared type desugars to a substitutable type, we would
return the replacement type without the sugar. I think in
practice this meant that ParenType would be lost sometimes.
Preserving this correctly is required for an upcoming CSDiag
change.
Note that there's a minor source-breaking change with enum
case constructors here. I've filed <rdar://problem/27261929>
to track sorting it out in Swift 3 mode.
Also an upcoming patch fixes another related issue and adds more
tests for case constructors.
Previously, getInterfaceType() would return getType() if no
interface type was set. Instead, always set an interface type
explicitly.
Eventually we want to remove getType() altogether, and this
brings us one step closer to this goal.
Note that ParamDecls are excempt from this treatment, because
they don't have a proper interface type yet. Cleaning this up
requires more effort.
This handles situation when overload for the subscript hasn't been resolved
by constraint solver, such might happen, for example, if solver was allowed to
produce solutions with free or unresolved type variables (e.g. when running diagnostics).
Resolves: <rdar://problem/27329076>, <rdar://problem/28619118>, <rdar://problem/2778734>.
When a generic parameter list fails to parse, we don't call
DeclContext::setGenericParams(), even though the generic
parameters are still available for name lookup.
This causes various crashes, which this patch fixes by
mapping the generic parameters to ErrorTypes.
Previously, getInterfaceType() would return getType() if no
interface type was set. Instead, always set an interface type
explicitly.
Eventually we want to remove getType() altogether, and this
brings us one step closer to this goal.
Note that ParamDecls are excempt from this treatment, because
they don't have a proper interface type yet. Cleaning this up
requires more effort.
Since 'try' or '=' can be folded with type expression at the same time,
Shallow simplifyTypeExpr() results '->' being escaped from TypeChecker.
For instance:
try () -> Int
Used to crash the compiler.
Also, never return nullptr for ArrowExpr. `1 -> Int` is invalid anyway.
Instead of leave ArrowExpr as is, construct ErrorTypeRepr for '1' part.
For constructing the dummy expression for missing initializer,
use the end location of the pattern instead of the location of the
current token.
Previous behavior used to build AST like:
{ if let x [eof]
|---| Pattern range
|---| Dummy introducer range
|------------| IfStmt range
|--------| BraceStmt range
Now:
{ if let x [eof]
|---| Pattern range
| Dummy introducer range
|------| IfStmt range
|--------| BraceStmt range
