Currently, XamlC never compiles bindings when Source is specified. Since #19995 has been merged, we do not need to skip compiling bindings with explicit source.

We should also be able to infer the x:DataType value based on the Source in several cases:

• When the source is RelativeSourceExtension with the mode Self or FindAncestor
• When the source is a reference to an object of a known type Source={x:Reference mySource} (blocked by [XamlC] Compile x:Reference #20726)
• When the source is an object with known type