Support RemoveUnused in Scala 3.4+ #1728

bjaglin · 2023-01-28T21:18:51Z

First half of #1682

bjaglin · 2023-05-18T12:56:25Z

Trying to understand why unused warnings don't show up as diagnostics in the SemanticDB files produced by dotty

➜  cat Test.scala                                                                       
//> using scala 3.3.0-RC6
//> using options -Wunused:all -Ysemanticdb

import java.util.List

object Test

➜  scala-cli Test.scala       
[warn] ./Test.scala:4:18
[warn] unused import
[warn] import java.util.List
[warn]                  ^^^^
[error]  No main class found

➜  metap Test.scala.semanticdb
tmp/Test.scala
--------------

Summary:
Schema => SemanticDB v4
Uri => tmp/Test.scala
Text => empty
Language => Scala
Symbols => 1 entries
Occurrences => 4 entries

Symbols:
_empty_/Test. => final object Test extends Object { self: Test.type => +1 decls }

Occurrences:
[3:7..3:11) => java/
[3:12..3:16) => java/util/
[3:17..3:21) => java/util/List#
[5:7..5:11) <= _empty_/Test.

tgodzik · 2023-05-18T14:29:53Z

Trying to understand why unused warnings don't show up as diagnostics in the SemanticDB files produced by dotty

➜  cat Test.scala                                                                       
//> using scala 3.3.0-RC6
//> using options -Wunused:all -Ysemanticdb

import java.util.List

object Test

➜  scala-cli Test.scala       
[warn] ./Test.scala:4:18
[warn] unused import
[warn] import java.util.List
[warn]                  ^^^^
[error]  No main class found

➜  metap Test.scala.semanticdb
tmp/Test.scala
--------------

Summary:
Schema => SemanticDB v4
Uri => tmp/Test.scala
Text => empty
Language => Scala
Symbols => 1 entries
Occurrences => 4 entries

Symbols:
_empty_/Test. => final object Test extends Object { self: Test.type => +1 decls }

Occurrences:
[3:7..3:11) => java/
[3:12..3:16) => java/util/
[3:17..3:21) => java/util/List#
[5:7..5:11) <= _empty_/Test.

Looks like we don't actually write them :| I will ask someone to take a look.

bjaglin · 2023-05-18T14:32:58Z

Looks like we don't actually write them :| I will ask someone to take a look.

@tgodzik I came to the same (sad) conclusion and was about to open a ticket on dotty

tgodzik · 2023-05-18T14:37:37Z

Looks like we don't actually write them :| I will ask someone to take a look.

@tgodzik I came to the same (sad) conclusion and was about to open a ticket on dotty

I will try a quick look, but that means it will mos tlikely be in 3.3.1 :/

bjaglin · 2023-05-18T14:40:13Z

scala/scala3#17535

anasbarg · 2023-12-11T10:11:57Z

Any updates regarding this PR?

tgodzik · 2023-12-11T10:17:26Z

I think we are waiting for the new Scala 3 release

bjaglin · 2023-12-11T18:00:37Z

I think we are waiting for the new Scala 3 release

Indeed, as soon as I see activity on the release train, I'll put that back in shape (and align with #1800). The dotty PR has been marked as backport:nominated, so hopefully this makes it to Scala 3.3 LTS 🤞

bjaglin · 2023-12-19T21:26:25Z

From the dotty PR

This particular change will land in 3.3.3 (that should have parity with 3.4.0). It will be available as an RC in late January and as a stable release in early March.

bjaglin · 2024-02-03T13:17:12Z

docs/rules/RemoveUnused.md

@@ -67,7 +64,7 @@ object Main {
 }
 ```

-Remove unused pattern match variables:
+Remove unused pattern match variables (requires `-Wunused:unsafe-warn-patvars` on Scala 3):


scala/scala3#16157 (comment)

bjaglin · 2024-02-03T13:19:11Z

docs/users/installation.md

@@ -9,7 +9,7 @@ title: Installation

 **Java LTS (8, 11, 17 or 21)**

-**Scala 2.12, 2.13 or 3.x** (all rules are not available for Scala 3.x)


only ExplicitResultTypes remains unsupported, and it's documented in rule docs, so I think we can drop this verbose disclaimer

bjaglin · 2024-02-03T13:21:14Z

scalafix-rules/src/main/scala/scalafix/internal/rule/RemoveUnused.scala

+      version.startsWith("3.0") ||
+        version.startsWith("3.1") ||
+        version.startsWith("3.2") ||
+        version.startsWith("3.3")


3.3.3 is likely to get the semanticdb fix but I'll update when I see it happening in a RC

bjaglin · 2024-02-03T13:21:58Z

scalafix-rules/src/main/scala/scalafix/internal/rule/RemoveUnused.scala

+          case _ => importee.pos
+        }
+        isUnusedImport.exists { unused =>
+          unused.start <= pos.start && pos.end <= unused.end


semanticdb diagnostics emitted by Scala 3 can be wider than those emiited by Scala 2's semanticdb-scalac (which do match the tree positions apart from renames, handled above)

bjaglin · 2024-02-03T13:52:59Z

docs/rules/RemoveUnused.md

@@ -87,7 +84,7 @@ object Main {
 }
 ```

-Remove unused function parameters:
+Remove unused function parameters (Scala 2 only):


Despite the presence of -Wunused:params and the explicit mention of it in scala/scala3#16157, I did not manage to get diagnostics (nor warnings), so I am leaving this out for now

$ metap ./scalafix-tests/input/target/jvm-3.4.0-RC2/meta/META-INF/semanticdb/scalafix-tests/input/src/main/scala/test/removeUnused/RemoveUnusedParams.scala.semanticdb scalafix-tests/input/src/main/scala/test/removeUnused/RemoveUnusedParams.scala ------------------------------------------------------------------------------ Summary: Schema => SemanticDB v4 Uri => scalafix-tests/input/src/main/scala/test/removeUnused/RemoveUnusedParams.scala Text => empty Language => Scala Symbols => 11 entries Occurrences => 28 entries Symbols: local0 => param unused: String local1 => param unused: String local2 => param used: String local3 => param unused: Long local4 => implicit param string: String test/removeUnused/UnusedParams. => final object UnusedParams extends Object { self: UnusedParams.type => +5 decls } test/removeUnused/UnusedParams.f. => val method fFunction1[String, Unit] test/removeUnused/UnusedParams.ff. => val method ffFunction1[String, Unit] test/removeUnused/UnusedParams.fs. => val method fsFunction2[String, Long, Unit] test/removeUnused/UnusedParams.g(). => method g(x: Function1[String, Unit]): Unit test/removeUnused/UnusedParams.g().(x) => param x: Function1[String, Unit] Occurrences: [3:8..3:12) => test/ [3:13..3:25) <= test/removeUnused/ [5:7..5:19) <= test/removeUnused/UnusedParams. [6:6..6:7) <= test/removeUnused/UnusedParams.f. [6:9..6:15) => scala/Predef.String# [6:19..6:23) => scala/Unit# [6:26..6:32) <= local0 [6:36..6:43) => scala/Predef.println(+1). [7:6..7:8) <= test/removeUnused/UnusedParams.ff. [7:12..7:18) <= local1 [7:20..7:26) => scala/Predef.String# [7:31..7:38) => scala/Predef.println(+1). [8:6..8:8) <= test/removeUnused/UnusedParams.fs. [8:12..8:16) <= local2 [8:18..8:24) => scala/Predef.String# [8:26..8:32) <= local3 [8:34..8:38) => scala/Long# [8:43..8:50) => scala/Predef.println(+1). [8:51..8:55) => local2 [9:6..9:7) <= test/removeUnused/UnusedParams.g(). [9:8..9:9) <= test/removeUnused/UnusedParams.g().(x) [9:11..9:17) => scala/Predef.String# [9:21..9:25) => scala/Unit# [9:28..9:32) => scala/Unit# [9:35..9:38) => scala/Predef.`???`(). [10:2..10:3) => test/removeUnused/UnusedParams.g(). [10:13..10:19) <= local4 [10:23..10:30) => scala/Predef.println(+1).

bjaglin · 2024-02-03T14:10:00Z

docs/developers/symbol-information.md

@@ -107,6 +107,7 @@ Use `MethodSignature.parameterLists` to look up parameters of a method.
 def printMethodParameters(symbol: Symbol): Unit = {
  symbol.info.get.signature match {
    case signature @ MethodSignature(typeParameters, parameterLists, _) =>
+      println("signature  = " + signature)


changes in ScalafixBuild enabled more unused warnings on the builds

bjaglin force-pushed the scala3unused branch 3 times, most recently from cf2ca39 to 37cd1ef Compare January 29, 2023 00:30

bjaglin mentioned this pull request Apr 15, 2023

Better support for cross compilation #1747

Open

bjaglin force-pushed the scala3unused branch from 37cd1ef to 44e5394 Compare May 1, 2023 11:20

bjaglin mentioned this pull request May 14, 2023

Refactor test execution #1756

Merged

bjaglin changed the title ~~support RemoveUnused on Scala 3.3.0-RC2~~ support RemoveUnused on Scala 3.3.0-RC6 May 15, 2023

bjaglin force-pushed the scala3unused branch 6 times, most recently from 0acaa71 to 0207e37 Compare May 18, 2023 12:54

bjaglin force-pushed the scala3unused branch from 0207e37 to c22d4d7 Compare May 18, 2023 13:13

bjaglin changed the title ~~support RemoveUnused on Scala 3.3.0-RC6~~ support RemoveUnused on Scala 3.3.0 May 18, 2023

bjaglin force-pushed the scala3unused branch from c22d4d7 to fec31ed Compare June 4, 2023 21:42

tanishiking mentioned this pull request Jun 30, 2023

Support OrganizeImports.removeUnused in Scala 3.4+ #1800

Merged

bjaglin changed the title ~~support RemoveUnused on Scala 3.3.0~~ support RemoveUnused in Scala 3 Jun 30, 2023

bjaglin changed the title ~~support RemoveUnused in Scala 3~~ Support RemoveUnused in Scala 3 Jun 30, 2023

bjaglin force-pushed the scala3unused branch 2 times, most recently from 0698713 to acbd4b7 Compare February 3, 2024 12:19

bjaglin changed the title ~~Support RemoveUnused in Scala 3~~ Support RemoveUnused in Scala 3.4+ Feb 3, 2024

test against scala 3.4.0-RC2

9f60582

bjaglin force-pushed the scala3unused branch 2 times, most recently from 7ba8bef to 945baa2 Compare February 3, 2024 13:16

bjaglin commented Feb 3, 2024

View reviewed changes

bjaglin added 3 commits February 3, 2024 14:35

dedup

ec1c5a4

2.12 handles just fine the more extensive 2.13 test input

c514aed

2.13 handles just fine a 2.12 test input

96642e5

bjaglin force-pushed the scala3unused branch from 945baa2 to 1108677 Compare February 3, 2024 13:49

bjaglin commented Feb 3, 2024

View reviewed changes

bjaglin force-pushed the scala3unused branch from 1108677 to 7ad87bc Compare February 3, 2024 14:02

bjaglin commented Feb 3, 2024

View reviewed changes

bjaglin force-pushed the scala3unused branch from 7ad87bc to 7b02f13 Compare February 3, 2024 14:10

bjaglin marked this pull request as ready for review February 3, 2024 14:10

support RemoveUnused on Scala 3.4+

a1097a7

bjaglin force-pushed the scala3unused branch from 7b02f13 to a1097a7 Compare February 3, 2024 14:47

bjaglin merged commit e4eb15d into scalacenter:main Feb 3, 2024
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This was referenced Feb 3, 2024

avoid flood of unused compiler warnings #1920

Merged

run RemoveUnused #1922

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bjaglin mentioned this pull request Feb 21, 2024

RemoveUnused: detect unused function parameters in Scala 3 #1937

Open

bjaglin mentioned this pull request May 1, 2024

improve docs about RemoveUnused #1992

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Support RemoveUnused in Scala 3.4+ #1728

Support RemoveUnused in Scala 3.4+ #1728

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bjaglin Feb 3, 2024

		@@ -9,7 +9,7 @@ title: Installation

		Java LTS (8, 11, 17 or 21)

		Scala 2.12, 2.13 or 3.x (all rules are not available for Scala 3.x)

Support RemoveUnused in Scala 3.4+ #1728

Support RemoveUnused in Scala 3.4+ #1728

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