Fix #9886: Disallow by-name trait parameters #10324
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That could be useful for future reference even if we don't pick it up now. |
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I made #10326 to record the status where it got abandoned. |
smarter
approved these changes
Nov 16, 2020
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Hi - Sad face emoji. I had no idea this was so difficult. For the record, I have documented a few reasons why this is a desired feature here, as I feel you have made a lot of efforts to turn Scala into a language with first-class support for type classes. I hope someone revisits the idea one day. |
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This is at best a partial fix. We disallow by-name trait parameters as an implementation restriction. It's better than crashing.
I tried for two days to make it work but gave up in the end. By-name parameters and traits are both very challenging to implement and their feature interaction in the various transformation stages is substantial. I will probably not go back to try to fix it again. If somebody wants to have a go, I can push the branch of my work so far.