Make UnmatchedCase errors lazy (#4049)
Make UnmatchedCase errors lazy (#4049)

uuhan/Idris-dev,uuhan/Idris-dev,uuhan/Idris-dev,uuhan/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,uuhan/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,uuhan/Idris-dev,kojiromike/Idris-dev,uuhan/Idris-dev