Detect and diagnose a contextual mismatch between expected
collection element type and the one provided (e.g. source
of the assignment or argument to a call) e.g.:
```swift
let _: [Int] = ["hello"]
func foo(_: [Int]) {}
foo(["hello"])
```
Diagnose extraneous use of address of (`&`) which could only be
associated with arguments to `inout` parameters e.g.
```swift
struct S {}
var a: S = ...
var b: S = ...
a = &b
```
KeyPath dynamic member lookup is limited to what key path itself
could do, so let's detect and diagnose invalid references just
like we do for regular key path expressions.
Resolves: rdar://problem/50376224
Detect difference in escapiness while matching function types
in the solver and record a fix that suggests to add @escaping
attribute where appropriate.
Also emit a tailored diagnostic when non-escaping parameter
type is used as a type of a generic parameter.
Since there is a way to mutate through use of writable keypath
diagnostics have to be adjusted to point to the members found
via keypath member lookup instead to using catch-all
"immutable base" diagnostic.
Instead of passing all of the information available in the diagnostic
to static functions, let's bring "default value" and "force unwrap"
fix-it logic under "missing optional unwrap diagnostic" umbrella.
This PR migrates instance member on type and type member on instance diagnostics handling to use the new diagnostics framework (fixes) and create more reliable and accurate diagnostics in such scenarios.
Detect that failed requirement comes from contextual type and use
that information to determine affected declaration.
Resolves: rdar://problem/47980354
If affected declaration is a static or instance memeber (excluding
operators) and failed requirement is declared in other nominal type
or extension, diagnose such problems as `in reference` instead of
claiming that requirement belongs to the member itself.
Situations like:
```swift
struct S {}
func foo(_ s: S.Type) {
_ = s()
}
```
Used to be diagnosed in solution application phase, which means that
solver was allowed to formed an incorrect solution.
- Attempting to construct class object using metatype value via
non-required initializer
- Referencing initializer of protocol metatype base
Both of the diagnostics are used by `AllowInvalidInitRef` fix.
* Make sure that base and unwrapped types aren't null
* Don't allocate `ForceOptional` fix if nothing has been unwrapped
in `simplifyApplicableFnConstraint`
* Add sugar reconstitution support to `FailureDiagnostic::resolveType`
* Format diagnostics a bit better
Try to fix constraint system in a way where member
reference is going to be defined in terms of its use,
which makes it seem like parameters match arguments
exactly. Such helps to produce solutions and diagnose
failures related to missing members precisely.
These changes would be further extended to diagnose use
of unavailable members and other structural member failures.
Resolves: rdar://problem/34583132
Resolves: rdar://problem/36989788
Resolved: rdar://problem/39586166
Resolves: rdar://problem/40537782
Resolves: rdar://problem/46211109
Fix to use subscript operator instead of spelled out name helps
to produce a solution, that makes it much easier to diagnose
problems precisely and provide proper fix-its, it also helps to
diagnose ambiguous cases, and stacks up nicely with other errors.
Detect and fix situations when (force) unwrap is used on
a non-optional type, this helps to diagnose invalid unwraps
precisely and provide fix-its.
Resolves: [SR-8977](https://bugs.swift.org/browse/SR-8977)
Resolves: rdar://problem/45218255
Suggest to add `()` (form a call) to correctly forward argument function
originated from `@autoclosure` parameter to function parameter itself
marked as `@autoclosure`.
Let's keep track of type mismatch between type deduced
for the body of the closure vs. what is requested
contextually, it makes it much easier to diagnose
problems like:
```swift
func foo(_: () -> Int) {}
foo { "hello" }
```
Because we can pin-point problematic area of the source
when the rest of the system is consistent.
Resolves: rdar://problem/40537960
