Emitting an error message about a pattern the user didn't write isn't awesome,
complain about the type requirements of an if/let binding specifically.
Swift SVN r28119
- Rewrite "if let x? = foo()" to "if let x = foo()"
- Rewrite "if let <complex refutable pattern> = foo()" to "if case let"
- Handle "if let case" just as well as "if case let" and fixit it to the correct form.
Swift SVN r27960
includes a number of QoI things to help people write the correct code. I will commit
the testcase for it as the next patch.
The bulk of this patch is moving the stdlib, testsuite and validation testsuite to
the new syntax. I moved a few uses of "as" patterns back to as? expressions in the
stdlib as well.
Swift SVN r27959
pattern, and can be chained together in conditions just like our other 'if let'
constructs. This only adds functionality, it doesn't change anything yet.
Swift SVN r27932
- <rdar://problem/16306600> QoI: passing a 'let' value as an inout results in an unfriendly diagnostic
- <rdar://problem/16927246> provide a fixit to change "let" to "var" if needing to mutate a variable
We now refer to an inout argument as such, e.g.:
t.swift:7:9: error: cannot pass 'let' value 'a' as inout argument
swap(&a, &b)
^
we also produce a note with a fixit to rewrite let->var in trivial cases where mutation is
being assed for, e.g.:
t.swift:3:3: note: change 'let' to 'var' to make it mutable
let a = 42
^~~
var
The note is produced by both Sema and DI.
Swift SVN r27774
We only require one of the patterns in a multi-pattern PBD to be conditional
as part of the swift 1 migation. Relax the requirements to allow unconditional
bindings next to conditional ones. This required moving some logic from the parser
to sema time.
Swift SVN r26987
Previously we would emit one diagnostic for the "you need a ?" and one for the "you can't use
a type annotation" errors. This doesn't work with Xcode because if you apply one, the other
gets clobbered. Merge these into one diagnostic that performs the removal and the insert.
Swift SVN r26902
This changes 'if let' conditions to take general refutable patterns, instead of
taking a irrefutable pattern and implicitly matching against an optional.
Where before you might have written:
if let x = foo() {
you now need to write:
if let x? = foo() {
The upshot of this is that you can write anything in an 'if let' that you can
write in a 'case let' in a switch statement, which is pretty general.
To aid with migration, this special cases certain really common patterns like
the above (and any other irrefutable cases, like "if let (a,b) = foo()", and
tells you where to insert the ?. It also special cases type annotations like
"if let x : AnyObject = " since they are no longer allowed.
For transitional purposes, I have intentionally downgraded the most common
diagnostic into a warning instead of an error. This means that you'll get:
t.swift:26:10: warning: condition requires a refutable pattern match; did you mean to match an optional?
if let a = f() {
^
?
I think this is important to stage in, because this is a pretty significant
source breaking change and not everyone internally may want to deal with it
at the same time. I filed 20166013 to remember to upgrade this to an error.
In addition to being a nice user feature, this is a nice cleanup of the guts
of the compiler, since it eliminates the "isConditional()" bit from
PatternBindingDecl, along with the special case logic in the compiler to handle
it (which variously added and removed Optional around these things).
Swift SVN r26150
un-type-annotated AnyObject binding in "if let", and allows general
patterns in if-let.
This also reverts some unrelated QoI improvements that went in with those
patches, but I'll add those back next.
Swift SVN r25507
two logically independent but related patches conflated together:
- Improve error recovery for malformed if/let conditions, particularly
when the user uses "," instead of &&. Add testcases for error recovery
requested by Jordan.
- Add a syntactic requirement that the pattern of an if/let condition be
a simple identifier or _. We allow slightly broader patterns here now,
but they will change in the future when refutable patterns are allowed.
It is best to be narrow and then open it up later so we can do a great
job of QoI then.
This includes the changes to the stdlib directory that I forgot to commit
with the patch the previous time.
Swift SVN r25408
- Improve error recovery for malformed if/let conditions, particularly
when the user uses "," instead of &&. Add testcases for error recovery
requested by Jordan.
- Add a syntactic requirement that the pattern of an if/let condition be
a simple identifier or _. We allow slightly broader patterns here now,
but they will change in the future when refutable patterns are allowed.
It is best to be narrow and then open it up later so we can do a great
job of QoI then.
Swift SVN r25371
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
if-let statements (also while and var, of course) that include multiple bindings
and where clauses.
SILGen support still remains, it currently just asserts on the new constructs.
Swift SVN r24239
These changes make the following improvements to how we generate diagnostics for expression typecheck failure:
- Customizing a diagnostic for a specific expression kind is as easy as adding a new method to the FailureDiagnosis class,
and does not require intimate knowledge of the constraint solver’s inner workings.
- As part of this patch, I’ve introduced specialized diagnostics for call, binop, unop, subscript, assignment and inout
expressions, but we can go pretty far with this.
- This also opens up the possibility to customize diagnostics not just for the expression kind, but for the specific types
involved as well.
- For the purpose of presenting accurate type info, partially-specialized subexpressions are individually re-typechecked
free of any contextual types. This allows us to:
- Properly surface subexpression errors.
- Almost completely avoid any type variables in our diagnostics. In cases where they could not be eliminated, we now
substitute in "_".
- More accurately indicate the sources of errors.
- We do a much better job of diagnosing disjunction failures. (So no more nonsensical ‘UInt8’ error messages.)
- We now present reasonable error messages for overload resolution failures, informing the user of partially-matching
parameter lists when possible.
At the very least, these changes address the following bugs:
<rdar://problem/15863738> More information needed in type-checking error messages
<rdar://problem/16306600> QoI: passing a 'let' value as an inout results in an unfriendly diagnostic
<rdar://problem/16449805> Wrong error for struct-to-protocol downcast
<rdar://problem/16699932> improve type checker diagnostic when passing Double to function taking a Float
<rdar://problem/16707914> fatal error: Can't unwrap Optional.None…Optional.swift, line 75 running Master-Detail Swift app built from template
<rdar://problem/16785829> Inout parameter fixit
<rdar://problem/16900438> We shouldn't leak the internal type placeholder
<rdar://problem/16909379> confusing type check diagnostics
<rdar://problem/16951521> Extra arguments to functions result in an unhelpful error
<rdar://problem/16971025> Two Terrible Diagnostics
<rdar://problem/17007804> $T2 in compiler error string
<rdar://problem/17027483> Terrible diagnostic
<rdar://problem/17083239> Mysterious error using find() with Foundation types
<rdar://problem/17149771> Diagnostic for closure with no inferred return value leaks type variables
<rdar://problem/17212371> Swift poorly-worded error message when overload resolution fails on return type
<rdar://problem/17236976> QoI: Swift error for incorrectly typed parameter is confusing/misleading
<rdar://problem/17304200> Wrong error for non-self-conforming protocols
<rdar://problem/17321369> better error message for inout protocols
<rdar://problem/17539380> Swift error seems wrong
<rdar://problem/17559593> Bogus locationless "treating a forced downcast to 'NSData' as optional will never produce 'nil'" warning
<rdar://problem/17567973> 32-bit error message is really far from the mark: error: missing argument for parameter 'withFont' in call
<rdar://problem/17671058> Wrong error message: "Missing argument for parameter 'completion' in call"
<rdar://problem/17704609> Float is not convertible to UInt8
<rdar://problem/17705424> Poor error reporting for passing Doubles to NSColor: extra argument 'red' in call
<rdar://problem/17743603> Swift compiler gives misleading error message in "NSLayoutConstraint.constraintsWithVisualFormat("x", options: 123, metrics: nil, views: views)"
<rdar://problem/17784167> application of operator to generic type results in odd diagnostic
<rdar://problem/17801696> Awful diagnostic trying to construct an Int when .Int is around
<rdar://problem/17863882> cannot convert the expression's type '()' to type 'Seq'
<rdar://problem/17865869> "has different argument names" diagnostic when parameter defaulted-ness differs
<rdar://problem/17937593> Unclear error message for empty array literal without type context
<rdar://problem/17943023> QoI: compiler displays wrong error when a float is provided to a Int16 parameter in init method
<rdar://problem/17951148> Improve error messages for expressions inside if statements by pre-evaluating outside the 'if'
<rdar://problem/18057815> Unhelpful Swift error message
<rdar://problem/18077468> Incorrect argument label for insertSubview(...)
<rdar://problem/18079213> 'T1' is not identical to 'T2' lacks directionality
<rdar://problem/18086470> Confusing Swift error message: error: 'T' is not convertible to 'MirrorDisposition'
<rdar://problem/18098995> QoI: Unhelpful compiler error when leaving off an & on an inout parameter
<rdar://problem/18104379> Terrible error message
<rdar://problem/18121897> unexpected low-level error on assignment to immutable value through array writeback
<rdar://problem/18123596> unexpected error on self. capture inside class method
<rdar://problem/18152074> QoI: Improve diagnostic for type mismatch in dictionary subscripting
<rdar://problem/18242160> There could be a better error message when using [] instead of [:]
<rdar://problem/18242812> 6A1021a : Type variable leaked
<rdar://problem/18331819> Unclear error message when trying to set an element of an array constant (Swift)
<rdar://problem/18414834> Bad diagnostics example
<rdar://problem/18422468> Calculation of constant value yields unexplainable error
<rdar://problem/18427217> Misleading error message makes debugging difficult
<rdar://problem/18439742> Misleading error: "cannot invoke" mentions completely unrelated types as arguments
<rdar://problem/18535804> Wrong compiler error from swift compiler
<rdar://problem/18567914> Xcode 6.1. GM, Swift, assignment from Int64 to NSNumber. Warning shown as problem with UInt8
<rdar://problem/18784027> Negating Int? Yields Float
<rdar://problem/17691565> attempt to modify a 'let' variable with ++ results in typecheck error about @lvalue Float
<rdar://problem/17164001> "++" on let value could give a better error message
Swift SVN r23782
You'll notice that emitting this diagnostic will make some already noisy closure-related errors slightly more so. This is unfortunate, but for the time-being it's better than crashing.
Swift SVN r21817
This already can't happen in most circumstances because of trailing closures, but we didn't explicitly disallow it at the beginning of a BraceStmt or following a statement production. Fixes the parser part of rdar://problem/17850752 (though there's a type checker bug there too).
Swift SVN r21663
JoeP helped tweak things to ensure that pointer conversions are still
considered, but we no longer need the disjunction on InOutExprs to accommodate
user-defined inout conversions.
This causes some regressions in error reporting:
<rdar://problem/17489983> inout type mismatches complain about '@lvalue inout T'
<rdar://problem/17489894> inout not rejected as operand to assignment operator
Swift SVN r19306
Allow IfStmts and WhileStmts to have as their condition either an expression, as usual, or a pattern binding introduced by 'var' or 'let', which will conditionally bind to the value inside an optional. Unlike normal pattern bindings, these bindings require an in-line initializer, which will be required to be Optional type. Parse variable bindings in this position, and type-check them by requiring an Optional on the right-hand side and unwrapping it to form the pattern type. Extend SILGen's lowering of if and while statements to handle conditionally binding variables.
Swift SVN r13146
