From 87cd8128c6de948f942c26e7562478da5e0cce8d Mon Sep 17 00:00:00 2001
From: Katarzyna Marek <kasia@marek.net>
Date: Tue, 5 Dec 2023 13:44:29 +0100
Subject: [PATCH] bugfix: don't show implicit conversions for synthetics

---
 .../pc/PcSyntheticDecorationsProvider.scala   |  3 +-
 .../SyntheticDecorationsLspSuite.scala        | 42 +++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/mtags/src/main/scala-2/scala/meta/internal/pc/PcSyntheticDecorationsProvider.scala b/mtags/src/main/scala-2/scala/meta/internal/pc/PcSyntheticDecorationsProvider.scala
index 37d047b3482..5e9adb54d41 100644
--- a/mtags/src/main/scala-2/scala/meta/internal/pc/PcSyntheticDecorationsProvider.scala
+++ b/mtags/src/main/scala-2/scala/meta/internal/pc/PcSyntheticDecorationsProvider.scala
@@ -95,7 +95,8 @@ final class PcSyntheticDecorationsProvider(
 
   object ImplicitConversion {
     def unapply(tree: Tree): Option[(String, Position)] = tree match {
-      case Apply(fun, args) if isImplicitConversion(fun) =>
+      case Apply(fun, args)
+          if isImplicitConversion(fun) && args.exists(_.pos.isRange) =>
         val lastArgPos = args.lastOption.fold(fun.pos)(_.pos)
         Some((fun.symbol.decodedName, lastArgPos))
       case _ => None
diff --git a/tests/unit/src/test/scala/tests/decorations/SyntheticDecorationsLspSuite.scala b/tests/unit/src/test/scala/tests/decorations/SyntheticDecorationsLspSuite.scala
index 0b02156f514..bfaf507b3ee 100644
--- a/tests/unit/src/test/scala/tests/decorations/SyntheticDecorationsLspSuite.scala
+++ b/tests/unit/src/test/scala/tests/decorations/SyntheticDecorationsLspSuite.scala
@@ -951,4 +951,46 @@ class SyntheticDecorationsLspSuite extends BaseLspSuite("implicits") {
       )
     } yield ()
   }
+
+  test("i4970") {
+    for {
+      _ <- initialize(
+        """|/metals.json
+           |{
+           |  "a": {
+           |    "libraryDependencies": [
+           |        "co.fs2::fs2-core:3.9.0"
+           |    ]
+           |  }
+           |}
+           |/a/src/main/scala/Main.scala
+           |import cats.effect.IO
+           |
+           |object Test {
+           |  def foo(str: fs2.Stream[IO, Int]) =
+           |    str.compile.to(Set)
+           |}
+           |""".stripMargin
+      )
+      _ <- server.didChangeConfiguration(
+        """{
+          |  "show-implicit-conversions-and-classes": true
+          |}
+          |""".stripMargin
+      )
+      _ <- server.didOpen("a/src/main/scala/Main.scala")
+      _ <- server.didSave("a/src/main/scala/Main.scala")(identity)
+      _ = assertNoDiagnostics()
+      _ = assertNoDiff(
+        client.syntheticDecorations,
+        """|import cats.effect.IO
+           |
+           |object Test {
+           |  def foo(str: fs2.Stream[IO, Int]) =
+           |    str.compile.to(supportsIterableFactory(Set))
+           |}
+           |""".stripMargin,
+      )
+    } yield ()
+  }
 }