Hello @soronpo,
Thanks for submitting this proposal! Please, feel free to submit a PR to this repository with the details of your proposal. These details would include a motivation section, a current description of the state-of-the-art on type alias precedence (and weird issues like the one @pathikrit mentions), and a description of your proposed solutions and the required changes to the spec.
For an exemplary proposal you can get inspiration from, see this one or have a look at this comment where @dwijnand gives you some advice on how to write a proposal (aside from this template that we provide). For full information on the steps to get a proposal through, check the official instructions here (note that I have to modify the section describing where to start discussing a proposal since the mentioned mailing lists are now retired). If you hurry up, we may review it the 14th February, when we have our next meeting! Otherwise, we’ll do it next month, so don’t stress ;).
For my fellow archeologists on the Internet, see this related thread in the now retired scala-sips mailing list in which @soronpo originally proposed this feature to the Scala language.
Thank you so much for this proposal. On a personal basis, I think that having type alias precedence behave exactly as operator precedence makes sense and helps Scala developers reason about the language more easily. I think that it is predictable and, therefore, what anyone would expect.