read "500." :: Double fails
Summary
A common rendering of floating point numbers is not recognized by the Read instance.
Steps to reproduce
Prelude> read "500.0" :: Double
500.0
Prelude> read "500" :: Double
500.0
Prelude> read "500." :: Double
*** Exception: Prelude.read: no parse
Expected behavior
Prelude> read "500." :: Double
500.0
Environment
- GHC version used: 8.6.5