Overload resolution simplification

Maurizio Cimadamore maurizio.cimadamore at oracle.com
Wed Aug 14 03:29:44 PDT 2013

On 14/08/13 10:57, Maurizio Cimadamore wrote:
> but it would seems that C# can use the target-type information _ahead_ 
> of overload resolution to perform inference, thus being able to reject 
> applicable candidates based on return mismatch (which Java cannot do). 
This is incorrect - I found this [1] which clearly states (Eric Lippert) 
that by design, in C# type information flows from argument types 
outwards, not the other way around. This means that several examples 
discussed in this mailing list wouldn't work in C# too, especially the 
ones around Comparator.comparing - in that case in fact, the only way to 
type-check the lambda is to instantiate the formal parameter of the 
method with the information that's available from the target-type 
context. Java won't do it because that would break the invariant that 
overload selection should not depend on target type. It seems like C# 
has a similar (sensible) restriction.

[1] - 


More information about the lambda-spec-observers mailing list