When trying to convert tuple type to existential look through
it's elements and convert found LValues to RValues (via load)
before applying erasure.
Resolves: <rdar://problem/27575060>.
PR #5857 started rejecting generic requirements that adding
constraints directly to 'Self', which means the requirements would be
unsatisfiable by some models. At the time that commit was merged, we
had thought the compiler crashed on all instances of this problem.
It turns out that, with assertions disabled, these protocols would be
accepted and could be used, so downgrade the error to a 'deprecated'
warning in Swift 3 compatibility mode.
It is possible to have requirement environments in which substitution
of the conforming type for Self into the requirement's signature would
result in substituted same-type requirements that no longer involve
type parameters. This triggered an assertion in the construction of
the requiremet environement; instead, just drop the requirement
because it is no longer interesting. Witness matching will simply fail
later one.
With this fix, it now because possible to add generic requirements to
a protocol that were unsatisfiable for certain models. For example,
the following protocol:
protocol P {
associatedtype A
associatedtype B
func f<T: P>(_: T) where T.A == Self.A, T.A == Self.B
}
can only be satisfied by conforming types for which Self.A ==
Self.B. SE-0142 will introduce a proper way to add such requirements
onto associated types. This commit makes any such attempt to add
requirements onto "Self" (or its associated types) ill-formed, so we
will reject the protocol P above with a diagnostic such as:
error: instance method requirement 'f' cannot add constraint
'Self.A == Self.B' on 'Self'
Fixes rdar://problem/29075927.
Fix two issues that cropped up in rdar://problem/29261689:
* We didn't have an ordering between two typo-corrected nested types
that were corrected to the same name, triggering an assertion, which
we resolve by ordering based on the original (pre-correction) names.
* In some cases, typo corrections would not be diagnosed because the
type checker wasn't able to map them to specific uses of that
type. Introduce a lame fallback case to make sure we get some
diagnostic---even though the location information is poor.
All of this needs an overhaul, but not today.
Fixes rdar://problem/29261689.
When cast expressions (conditional or forced downcasts) are part
of the closure expression with invalid parameters or return type,
they are not going be to folded by PreCheckExpression, which means
that they are not going to have sub-expression (from) set.
Resolves: <rdar://problem/27464577>.
Make SolverState manage whether the ConstraintSystem it belongs to has a
current SolverState.
Also a couple minor formatting fixes for ternary expressions involving
solverState.
Store leading a trailing "trivia" around a token, such as whitespace,
comments, doc comments, and escaping backticks. These are syntactically
important for preserving formatting when printing ASTs but don't
semantically affect the program.
Tokens take all trailing trivia up to, but not including, the next
newline. This is important to maintain checks that statements without
semicolon separators start on a new line, among other things.
Trivia are now data attached to the ends of tokens, not tokens
themselves.
Create a new Syntax sublibrary for upcoming immutable, persistent,
thread-safe ASTs, which will contain only the syntactic information
about source structure, as well as for generating new source code, and
structural editing. Proactively move swift::Token into there.
Since this patch is getting a bit large, a token fuzzer which checks
for round-trip equivlence with the workflow:
fuzzer => token stream => file1
=> Lexer => token stream => file 2 => diff(file1, file2)
Will arrive in a subsequent commit.
This patch does not change the grammar.
Disallows solutions containing free type variables on the final step of
witness matching, because that would yield incorrect results when witness
type has free type variables as well.
Resolves: <rdar://problem/27249691>.
Type substitution works on a fairly narrow set of types: generic type
parameters (to, e.g., use a generic) and archetypes (to map out of a
generic context). Historically, it was also used with
DependentMemberTypes, but recent refactoring to eliminate witness
markers eliminate that code path.
Therefore, narrow TypeSubstitutionMap's keys to SubstitutableType,
which covers archetypes and generic type parameters. NFC
Simplify some control-flow to reduce indentation and eliminate an
unneeded flag variable.
Also update a comment to match the code that went in with
b5500b8600.
This function had a weird, pre-ProtocolConformanceRef interface that
returned true when the type conformed to the protocol, then had a
separate indirect return value for the concrete conformance (if there
is one). Refactor this API, and the similar
TypeChecker::containsProtocol(), to produce an optional
ProtocolConformanceRef, which is far more idiomatic and easier to
use. Push ProtocolConformanceRef into a few more places. Should be NFC
On rare occasions, malformed programs can allow an UNCHECKED_EXPR (e.g. ArrowExpr) to escape type checking. The erroneous expression may have sub-expressions which aren't fully typechecked, so we can't safely visit them.
An environment is always associated with a location with a signature, so
having them separate is pointless duplication. This patch also updates
the serialization to round-trip the signature data.
Modify TypeChecker::coerceParameterListToType to always validate and consider only
valid contextual types (contains: no undefined, error, or type variables etc.) for
argument type coercion, such logic prevents erasure of important explicitly specified
type information attached to parameters of the closure expressions being diagnosed.
Resolves: SR-2994.
