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.
Allow certain bindings and conversions involving non-escaping
function types to succeed in "diagnostic" mode to gather fixes
and diagnose such problems better, expecially related to
conversions to 'Any' and generic parameters.
Resolves: rdar://problem/38648760
Remove function-to-function type match score increase, which should only
happen contextually in presence of other restrictions, this used to fix
the case related to matching of arrays of functions with and w/e `throws`
as function parameters which used to be ambigious, and now handled by
collection-upcast conversion score.
Resolves: rdar://problem/35142121
The formal type of methods should be (Type) -> (Args...) -> (),
not Type -> (Args...) -> ().
This only matters in Swift 4 mode, where it was preventing the
newly-added test case from type checking.
Fixes <rdar://problem/31725325>.
This fixes a case where we would allow a function conversion
in Swift 3 mode, but not in Swift 4. We were incorrectly stripping
off ParenTypes, which was OK in Swift 3, but with the implementation
of SE-0110 this resulted in a type mismatch.
Fixes <rdar://problem/31969605>.
