WIP Resolving TransformerF and Transformer ambiguity

[ulanzetz]

Sometimes there is necessary to define TransformerF and Transformer rules that have intersected signatures. Current mechanism of TransformerF try to find both Transformer and TransformerF instances and it's not able to define priority using common Scala implicit priority hacks. It seems logical to me to choose Transformer instance as more priority and don't fail with compilation error on ambiguity. but if it's not possible because it breaks backward compatibility, maybe we can define special flag for this (but I'm not sure about adding this flag to FlagsDsl, because it can be used only for intoF).

Example of ambiguity is presented in tests, Coercible is analog of type class from newtype lib.

WDYT, @krzemin ?

[codecov[bot]]

Codecov Report

Merging #197 (459d38d) into master (577707a) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #197   +/-   ##
=======================================
  Coverage   99.55%   99.55%           
=======================================
  Files          25       25           
  Lines         674      679    +5     
  Branches       72       77    +5     
=======================================
+ Hits          671      676    +5     
  Misses          3        3           

Impacted Files	Coverage Δ
...ney/internal/macros/TransformerConfigSupport.scala	100.00% <100.00%> (ø)
...nd/chimney/internal/macros/TransformerMacros.scala	99.24% <100.00%> (+<0.01%)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 577707a...459d38d. Read the comment docs.

[Phill101]

@krzemin, it would be so nice to see this feature 🙏

[MateuszKubuszok]

Thank you for you contribution! Currently we are working on replacing TransformerF with a build-in structure for validated/failing transformations in https://github.com/scalalandio/chimney/pull/235. You can check the PR and give us an early feedback on its current behavior.