Syntactically invalid Rust produces a garbled error

[alexcrichton]

First thing's first, this is an awesome extension! I've loved using it so far!

Next thing, I've noticed that when you've got syntactically incorrect source code the error is often pretty difficult to follow. What I believe is happening is that syn is (rightfully) failing to parse, but syn's error messages are much worse than the compiler's. In the case that syn fails, could the compiler be run anyway to generate a nicer error message?