fix: go to definition and hover for named args in pattern match (#23956)

fixes: scalameta/metals#7763

Author: tgodzik

presentation-compiler/src/main/dotty/tools/pc/MetalsInteractive.scala

@@ -120,8 +120,9 @@ object MetalsInteractive:
       // For a named arg, find the target `DefDef` and jump to the param
       case NamedArg(name, _) :: Apply(fn, _) :: _ =>
         val funSym = fn.symbol
-        if funSym.is(Synthetic) && funSym.owner.is(CaseClass) then
-          val sym = funSym.owner.info.member(name).symbol
+        lazy val owner = funSym.owner.companionClass
+        if funSym.is(Synthetic) && owner.is(CaseClass) then
+          val sym = owner.info.member(name).symbol
           List((sym, sym.info, None))
         else
           val paramSymbol =
@@ -130,6 +131,13 @@ object MetalsInteractive:
           val sym = paramSymbol.getOrElse(fn.symbol)
           List((sym, sym.info, None))
 
+      case NamedArg(name, _) :: UnApply(s, _, _) :: _ =>
+        lazy val owner = s.symbol.owner.companionClass
+        if s.symbol.is(Synthetic) && owner.is(CaseClass) then
+          val sym = owner.info.member(name).symbol
+          List((sym, sym.info, None))
+        else Nil
+
       case (_: untpd.ImportSelector) :: (imp: Import) :: _ =>
         importedSymbols(imp, _.span.contains(pos.span)).map(sym =>
           (sym, sym.info, None)

presentation-compiler/test/dotty/tools/pc/tests/definition/PcDefinitionSuite.scala

@@ -647,3 +647,34 @@ class PcDefinitionSuite extends BasePcDefinitionSuite:
          |    export scala.collection.immutable.V/*scala/collection/immutable/Vector. Vector.scala*/@@ector
          |""".stripMargin
     )
+
+  @Test def i7763 =
+    check(
+      """|case class MyItem(<<name>>: String)
+         |
+         |def handle(item: MyItem) =
+         |  item match {
+         |    case MyItem(na@@me = n2) => println(n2)
+         |  }
+         |""".stripMargin
+    )
+
+  @Test def `i7763-neg` =
+    check(
+      """|object MyItem:
+        |  def unapply(name: String): Option[Int] = ???
+        |
+        |def handle(item: String) =
+        |  item match {
+        |    case MyItem(na@@me = n2) => println(n2)
+        |  }
+        |""".stripMargin
+    )
+
+  @Test def `i7763-apply` =
+    check(
+      """|case class MyItem(<<name>>: String)
+         |
+         |def handle(item: String) = MyItem(na@@me = item)
+         |""".stripMargin
+    )

presentation-compiler/test/dotty/tools/pc/tests/hover/HoverTermSuite.scala

@@ -938,3 +938,15 @@ class HoverTermSuite extends BaseHoverSuite:
          |""".stripMargin,
       "val aa: Int".hover
     )
+
+  @Test def i7763 =
+    check(
+      """|case class MyItem(name: String)
+         |
+         |def handle(item: MyItem) =
+         |  item match {
+         |    case MyItem(na@@me = n2) => println(n2)
+         |  }
+         |""".stripMargin,
+      "val name: String".hover
+    )