When a method is called with fewer than two parameter lists,
transform it into a fully-applied call by wrapping it in a
closure.
Eg,
Foo.bar => { self in { args... self.bar(args...) } }
foo.bar => { self in { args... self.bar(args...) } }(self)
super.bar => { args... in super.bar(args...) }
With this change, SILGen only ever sees fully-applied calls,
which will allow ripping out some code.
This new way of doing curry thunks fixes a long-standing bug
where unbound references to protocol methods did not work.
This is because such a reference must open the existential
*inside* the closure, after 'self' has been applied, whereas
the old SILGen implementation of curry thunks really wanted
the type of the method reference to match the opened type of
the method.
A follow-up cleanup will remove the SILGen curry thunk
implementation.
Fixes rdar://21289579 and https://bugs.swift.org/browse/SR-75.
The SILGen testsuite consists of valid Swift code covering most language
features. We use these tests to verify that no unknown nodes are in the
file's libSyntax tree. That way we will (hopefully) catch any future
changes or additions to the language which are not implemented in
libSyntax.
