Pavel Yaskevich f6b7df161c [ConstraintSystem] Increase impact of a missing conformance related to stdlib type ...

Prioritize type mismatches over conformance failures when stdlib
types are involved because it wouldn't be appropriate to suggest
to add such a conformance, so the problem is most likely related
to something else e.g. other overload choice has a better fix.

Consider following example:

```swift
struct S {
  init(_: Double) {}
  init<T: BinaryInteger>(_: T) {}
}

_ = S(Double("0"))
```

In cases like that it's better to prefer failable initializer
which takes a `String` and returns `Double?` and diagnose a
problem related to missing optional unwrap instead of missing
conformances related to a `String` argument of other `Double`
initializer just because it returns a concrete type.

2020-02-17 16:09:11 -08:00

361 KiB

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