types. Use this simple overload resolution scheme in both type
checking and type coercion, simplifying both code paths a bit.
There is one significant semantic change here: we allow overload
resolution to operate on (structured) dependent arguments, which
allows for more overload filtering before we come in with the type
coercion hammer. For example, we can now properly type-check
var x : int32;
x + 0;
Swift SVN r1310
aren't needed for the lexer proper (which just needs a buffer to dig
through). Also, make it possible to suppress lexer diagnostics merely
by not giving it a diagnostic engine to work with.
Swift SVN r852
actually render emitted diagnostics. This is both a useful
generalization (we expect to have a number of other
DiagnosticConsumers down the road, as Clang does) and is also
important now to avoid a layering violation when adjusting the source
location at the end of a SourceRange to the end of the token.
Swift SVN r850
Note that I had to re-implement llvm::Optional, since it lamely requires a default constructor. At some point, I'll push a proper implementation back to LLVM.
Swift SVN r845
