If I I go Toslink out from my CD player to my receiver, do I lose the benefits of CD error correction?
the Toslink transmits error-corrected PCM audio to the receiver. A CD without error-correction won't give acceptable audio.
TOSLINK is not pure bitwise audio data from a CD. Data from a CD is decoded in the player, and then encoded as a PCM or compressed stream through S/PDIF, be it optical or coax.
In case you're interested in how CDs work, and how the bitstream is decoded, here's a nice video:
https://www.youtube.com/watch?v=sAbhPeTp51s
The same channel took a look at TOSLINK and its limitations:
https://www.youtube.com/watch?v=ICcEOXVZ3F0 (quite informative, how fiber isn't the end-all and be-all when it's a cheap and simple implementation like TOSLINK)
If I I go Toslink out from my CD player to my receiver, do I lose the benefits of CD error correction?
As it was stated before, no you don't loose the CD error correction.
The audio data send out over S/PDIF or Toslink is exactly the same that will be send to the internal DA circuitry in the player; the difference is that it is a serial data stream that includes additional informations.
In case of using modern refined receivers it will probably make no difference, just keep in mind when using Toslink with older gear that the impact of jitter (when measured at the analog outputs) can be higher compared to usage of the S/PDIF connection.
Ripping the CD to digital can catch and correct errors that the CD player will miss.