From 7a9fa821251b65a137dce1bc74a62f0d3ef33384 Mon Sep 17 00:00:00 2001
From: Jakub Ciesluk <323892@uwr.edu.pl>
Date: Fri, 15 Sep 2023 16:31:52 +0200
Subject: [PATCH] bugfix: Incorrect docstring  on parameters

Previously, we were not changing tree when entering class/method parameters and type parameters while indexing,
which resulted in showing incorrect docstring.
---
 .../meta/internal/mtags/ScalaMtags.scala      | 10 ++-
 .../scala/tests/hover/HoverDocSuite.scala     | 86 +++++++++++++++++++
 2 files changed, 95 insertions(+), 1 deletion(-)

diff --git a/mtags/src/main/scala/scala/meta/internal/mtags/ScalaMtags.scala b/mtags/src/main/scala/scala/meta/internal/mtags/ScalaMtags.scala
index be791e692e6..6d35f628eda 100644
--- a/mtags/src/main/scala/scala/meta/internal/mtags/ScalaMtags.scala
+++ b/mtags/src/main/scala/scala/meta/internal/mtags/ScalaMtags.scala
@@ -60,10 +60,12 @@ class ScalaMtags(val input: Input.VirtualFile, dialect: Dialect)
           paramss: List[List[Term.Param]],
           isPrimaryCtor: Boolean
       ): Unit = {
+        val old = myCurrentTree
         for {
           params <- paramss
           param <- params
         } {
+          myCurrentTree = param
           withOwner() {
             if (isPrimaryCtor) {
               param.name match {
@@ -76,19 +78,24 @@ class ScalaMtags(val input: Input.VirtualFile, dialect: Dialect)
             }
           }
         }
-
+        myCurrentTree = old
       }
       def enterTypeParameters(tparams: List[Type.Param]): Unit = {
+        val old = myCurrentTree
         for {
           tparam <- tparams
         } {
+          myCurrentTree = tparam
           withOwner() {
             super.tparam(tparam.name, Kind.TYPE_PARAMETER, 0)
           }
         }
+        myCurrentTree = old
       }
       def enterPatterns(ps: List[Pat], kind: Kind, properties: Int): Unit = {
+        val old = myCurrentTree
         ps.foreach { pat =>
+          myCurrentTree = pat
           pat.traverse {
             case Pat.Var(name) =>
               withOwner() {
@@ -101,6 +108,7 @@ class ScalaMtags(val input: Input.VirtualFile, dialect: Dialect)
             case _ =>
           }
         }
+        myCurrentTree = old
       }
       def disambiguatedMethod(
           member: Member,
diff --git a/tests/cross/src/test/scala/tests/hover/HoverDocSuite.scala b/tests/cross/src/test/scala/tests/hover/HoverDocSuite.scala
index 048640f531a..deb5923b4e2 100644
--- a/tests/cross/src/test/scala/tests/hover/HoverDocSuite.scala
+++ b/tests/cross/src/test/scala/tests/hover/HoverDocSuite.scala
@@ -293,6 +293,92 @@ class HoverDocSuite extends BaseHoverSuite {
        |""".stripMargin,
   )
 
+  check(
+    "class-param",
+    """|
+       |/**
+       |  * Doc about class
+       |  *
+       |  */
+       |class Alpha(abc: Int) {
+       |  val y = <<a@@bc>>
+       |}
+       |
+       |""".stripMargin,
+    """|```scala
+       |private[this] val abc: Int
+       |```
+       |""".stripMargin,
+    compat = Map(
+      "3" ->
+        """|```scala
+           |val abc: Int
+           |```
+           |""".stripMargin
+    ),
+  )
+
+  check(
+    "class-type-param",
+    """|
+       |/**
+       |  * Doc about class
+       |  *
+       |  */
+       |class Alpha[T](abc: T) {
+       |  val y: <<@@T>> = abc
+       |}
+       |
+       |""".stripMargin,
+    """|```scala
+       |T: T
+       |```
+       |""".stripMargin,
+    compat = Map(
+      "3" ->
+        """|```scala
+           |type T: T
+           |```
+           |""".stripMargin
+    ),
+  )
+
+  check(
+    "method-param",
+    """|
+       |object O {
+       |  /**
+       |    * Doc about method
+       |    */
+       |  def foo(abc: Int) = <<a@@bc>> + 1
+       |
+       |}
+       |
+       |""".stripMargin,
+    """|```scala
+       |abc: Int
+       |```
+       |""".stripMargin,
+  )
+
+  check(
+    "method-type-param",
+    """|
+       |object O {
+       |  /**
+       |    * Doc about method
+       |    */
+       |  def foo[T](abc: T): <<@@T>> = abc
+       |
+       |}
+       |
+       |""".stripMargin,
+    """|```scala
+       |T: T
+       |```
+       |""".stripMargin,
+  )
+
   check(
     "universal-apply".tag(IgnoreScala2),
     """|