Sergey Torgashov

[proposal] Literal Scala versions

4

**Disclaimer**: everything is controversial here! Also for now it is supposed to fail binary compatibility checks against v0.1.1. Honestly, I am not sure if it is even feasible to maintain...

Missing Scala Versions

1

Do I understand correctly that this list is supposed to contain all supported Scala versions eventually (i.e. up to 2.12.16 and 2.13.8)? https://github.com/typelevel/scalac-options/blob/1a75eef01b7e0d338089ec1619eeba3a595c0079/lib/src/main/scala/org/typelevel/scalacoptions/ScalaVersion.scala#L27-L39 Or are there only those versions listed...

No way to create a Fold to a specific A type without Encoder[A]

1

### Problem Consider a JSON: ```json5 {"foo": {"bar": {"goo": {"car": { /* some complex structure inside */ }}}}} ``` We need to parse and decode the `car` object into some...

SQL mapping does not work for recursive queries to DB tables with qualified names

1

### Summary If DB tables with [qualified names](https://www.postgresql.org/docs/current/ddl-schemas.html) are used in a mapping, then recursive GraphQL queries do not work and fail with a cryptic error. Note: checked for `DoobieMapping`...

`OrganizeImports` rule can break compilation

2

### Actual Behavior A real example. Consider a project with the following two dependencies: - [circe-core](https://mvnrepository.com/artifact/io.circe/circe-core) - [fs2-io](https://mvnrepository.com/artifact/co.fs2/fs2-io) Also consider a scala file with the following imports section: ```scala import...

Renaming `specialized` on import results in "unused import" warnings

3

## Compiler version v3.3.3, v3.4.2 ## Minimized code ```scala import scala.{specialized => sp} trait ImportUnusedSpecializedRename[@sp Int] ``` Script that I used for testing: ```sh set -v scala-cli clean ImportUnusedSpecializedRename.scala scala-cli...

There are several classes or other identifiers across Cats that were made public initially even though they are not supposed to be accessible outside of the library: - `cats.kernel.instances.SeqMonoid` -...

[PROPOSAL] Aliases for methods `traverse_` and `sequence_`

7

Since `fa.traverse_(fun)` and `fa.sequence_` are semantically the same as `fa.traverse(fun).void` and `fa.sequence.void` I would propose to add aliases `traverseVoid` and `sequenceVoid` for them correspondingly. ### Why? In two words: discoverability...

Optimize `distinct`/`distinctBy` implementations for non-empty collections

1

A follow up for #4608 (see my comment https://github.com/typelevel/cats/pull/4608#discussion_r1626935568). For an example of a pretty well optimized implementation one could check out the corresponding methods in `Chain`: https://github.com/typelevel/cats/blob/930f25c544c787fe6703349090b5210a35249e70/core/src/main/scala/cats/data/Chain.scala#L797-L813 https://github.com/typelevel/cats/blob/930f25c544c787fe6703349090b5210a35249e70/core/src/main/scala/cats/data/Chain.scala#L826-L842

Proposal: `unique` and `option`-alike combinators

11

Inspired by Doobie's `unique` and `option` queries: https://github.com/typelevel/doobie/blob/1ad3ad5e195d89becbd4097677f738a0b10aa5df/modules/core/src/main/scala/doobie/util/query.scala#L127-L139 In fact, those two are pretty common use cases: after receiving a collection of items from somewhere, we may want to make...