Thanks for the mention, Gene. Thanks for being an early adopter, and keep those bugs and feedback coming in!
As far as performance vs C - there's not a lot of features that incur dynamic dispatch: virtual method calls, dynamic casts (as/is keywords), and direct interface dispatch. When you use interfaces as generic constraints, those monomorph into static dispatches unless the implementing method itself is virtual.
For C-style code, however, the performance should be the same as the C equivalent in Clang. File a bug if it isn't!
As far as performance vs C - there's not a lot of features that incur dynamic dispatch: virtual method calls, dynamic casts (as/is keywords), and direct interface dispatch. When you use interfaces as generic constraints, those monomorph into static dispatches unless the implementing method itself is virtual.
For C-style code, however, the performance should be the same as the C equivalent in Clang. File a bug if it isn't!