In member ref expressions, if the base is optional, and the expected
expression result is either optional or unknown, suggest a fixit that
makes it into an optional chain expr rather than force unwrapping.
Since in many cases the actual fixit is emitted during diagnosis, and
thus, while type checking sub exprs with no contextual type specified
(so nothing to check for preferring optionality), we also need an
additional flag to pass down from FailureDiagnosis for whether we
prefer to fix as force unwrapping or optional chaining.
I attempted to do this same job via providing a convert type but
setting the ConvertTypeIsOnlyAHint flag on the type checker, but
unfortunately there are a lot of other moving parts that look at that
type, even if it is only supposed to be a hint, so an additional flag
to the CS ended up being cleaner.
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.
and probably others.
When we're type-checking a failed ApplyExpr that has an overload set that
prevents getting a specific type to feed into the initial typechecking of
the argument list, ranking can often narrow down the list of candidates
further, to the point where there is only one candidate left or where all
candidates agree that one argument is wrong.
In this case, re-type-check the subexpr with the expected type. In the case of
rdar://problem/22243469 we now produce:
t.swift:6:11: error: invalid conversion from throwing function of type '() throws -> ()' to non-throwing function type '() -> Void'
process {
^
instead of:
t.swift:6:3: error: cannot invoke 'process' with an argument list of type '(() throws -> ())'
process {
^
t.swift:6:3: note: overloads for 'process' exist with these partially matching parameter lists: (UInt, fn: () -> Void)
process {
^
Which is a heck of a lot less specific. Similarly, in the testcase from rdar://23550816, instead
of producing:
takeTwoFuncsWithDefaults { $0 + 1 }
error: cannot invoke 'takeTwoFuncsWithDefaults' with an argument list of type '((Int -> Int)?)'
note: expected an argument list of type '(f1: (Int -> Int)?, f2: (String -> String)?)'
we now produce:
error: cannot convert value of type '_ -> Int' to expected argument type '(String -> String)?'
which is a lot closer to what we want to complain about.
fixit hint in CSDiags instead of being a FixKind. This resolves a number of issues with
it, particularly that it didn't actually check to see if the function in question takes
a () argument or not.
This fixes:
<rdar://problem/21692808> QoI: Incorrect 'add ()' fixit with trailing closure
among other issues.
Swift SVN r31728
<rdar://problem/18397777> QoI: special case comparisons with nil
<rdar://problem/18042123> QoI: Fixit for "if !optional" should suggest "if optional == nil"
Swift SVN r31204
- Have DiagnosticEngine produce "aka" annotations for sugared types.
- Fix the "optional type '@lvalue C?' cannot be used as a boolean; test for '!= nil' instead"
diagnostic to stop printing @lvalue noise.
This addresses:
<rdar://problem/19036351> QoI: Print minimally-desugared 'aka' types like Clang does
Swift SVN r30587
Now for:
let req = NSURLRequest(URL: NSURL(string: "<some url>")!)?
instead of producing:
test.swift:2:58: error: could not find an overload for 'init' that accepts the supplied
we produce the correct diagnostic, with a fixit:
error: cannot use optional chaining on non-optional value of type 'NSURLRequest'
let req = NSURLRequest(URL: NSURL(string: "<some url>")!)?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
This also consolidates some existing diagnostics to improve their wording.
Swift SVN r30049
We were using getRValueType() and getRValueObjectType() when
setting up the constraint, but getRValueType() when simplifying
it. This led to a crash if the type was a single-argument tuple
with a named argument.
Swift SVN r29376
optional evaluation context that produced the optional.
<rdar://problem/20377684> Oscillating fixit for optional chain calling method that returns non-optional
Swift SVN r28212
necessary. Wrap forced optional fixit in parens if necessary.
<rdar://problem/20029786> Swift compiler sometimes suggests changing "as!" to "as?!"
Swift SVN r26189
Most tests were using %swift or similar substitutions, which did not
include the target triple and SDK. The driver was defaulting to the
host OS. Thus, we could not run the tests when the standard library was
not built for OS X.
Swift SVN r24504
Previously the "as" keyword could either represent coercion or or forced
downcasting. This change separates the two notions. "as" now only means
type conversion, while the new "as!" operator is used to perform forced
downcasting. If a program uses "as" where "as!" is called for, we emit a
diagnostic and fixit.
Internally, this change removes the UnresolvedCheckedCastExpr class, in
favor of directly instantiating CoerceExpr when parsing the "as"
operator, and ForcedCheckedCastExpr when parsing the "as!" operator.
Swift SVN r24253
We now provide fixits for if-expressions, point out the actual conditional expression (as opposed to the surrounding expression),
support unary '!' applications and avoid printing type variables in the diagnostic.
Swift SVN r20992
Start capitalizing on some of the new diagnostic machinery in a few different ways:
- When mining constraints for type information, utilize constraints "favored" by the overload resolution process.
- When printing type variables, if the variable was created by opening a literal expression, utilize the literal
default type or conformance if possible.
- Utilize syntactic information when crafting diagnostics:
- If the constraint miner can produce a better diagnostic than the recorded failure, diagnose via constraints.
- Factor in the expression kind when choosing which types to include in a diagnostic message.
- Start customizing diagnostics based on the amount of type data available.
What does all this mean?
- Fewer type variables leaking into diagnostic messages.
- Far better diagnostics for overload resolution failures. Specifically, we now print proper argument type data
for failed function calls.
- No more "'Foo' is not convertible to 'Foo'" error messages
- A greater emphasis on type data means less dependence on the ordering of failed constraints. This means fewer
inscrutable diagnostics complaining about 'UInt8' when all the constituent expressions are of type Float.
So we still have a ways to go, but these changes should greatly improve the number of head-scratchers served up
by the type checker.
These changes address the following radars:
rdar://problem/17618403
rdar://problem/17559042
rdar://problem/17007456
rdar://problem/17559042
rdar://problem/17590992
rdar://problem/17646988
rdar://problem/16979859
rdar://problem/16922560
rdar://problem/17144902
rdar://problem/16616948
rdar://problem/16756363
rdar://problem/16338509
Swift SVN r20927
This causes a regression in error reporting where there are potential fixes: <rdar://problem/17741575> Other than that, everything works.
Swift SVN r20230
There's a bit of a reshuffle of the ExplicitCastExpr subclasses:
- The existing ConditionalCheckedCastExpr expression node now represents
"as?".
- A new ForcedCheckedCastExpr node represents "as" when it is a
downcast.
- CoerceExpr represents "as" when it is a coercion.
- A new UnresolvedCheckedCastExpr node describes "as" before it has
been type-checked down to ForcedCheckedCastExpr or CoerceExpr. This
wasn't a strictly necessary change, but it helps us detangle what's
going on.
There are a few new diagnostics to help users avoid getting bitten by
as/as? mistakes:
- Custom errors when a forced downcast (as) is used as the operand
of postfix '!' or '?', with Fix-Its to remove the '!' or make the
downcast conditional (with as?), respectively.
- A warning when a forced downcast is injected into an optional,
with a suggestion to use a conditional downcast.
- A new error when the postfix '!' is used for a contextual
downcast, with a Fix-It to replace it with "as T" with the
contextual type T.
Lots of test updates, none of which felt like regressions. The new
tests are in test/expr/cast/optionals.swift.
Addresses <rdar://problem/17000058>
Swift SVN r18556
Introduce some infrastructure that allows us to speculatively apply
localized fixes to expressions during constraint solving to fix minor
typos and omissions. At present, we're able to introduce the fixes
during constraint simplification, prefer systems with fewer fixes when
there are multiple fixes, and diagnose the fixes with Fix-Its.
Actually rewriting the AST to reflect what the Fix-Its are doing is
still not handled.
As a start, introduce a fix that adds '()' if it appears to have been
forgotton, producing a diagnostic like this if it works out:
t.swift:8:3: error: function produces expected type 'B'; did you mean
to call it with '()'?
f(g)
^
()
Note that we did regress in one test case
(test/NameBinding/multi-file.swift), because that diagnostic was
getting lucky with the previous formulation.
Swift SVN r16937
