bugfix: Backticked named arguments

Author: jkciesluk

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

@@ -200,6 +200,12 @@ abstract class PcCollector[T](
         val realName = arg.name.stripModuleClassSuffix.lastPart
         if pos.span.start > arg.span.start && pos.span.end < arg.span.point + realName.length
         then
+          val length = realName.toString.backticked.length()
+          val pos = arg.sourcePos.withSpan(
+            arg.span
+              .withEnd(arg.span.start + length)
+              .withPoint(arg.span.start)
+          )
           appl.symbol.paramSymss.flatten.find(_.name == arg.name).map { s =>
             // if it's a case class we need to look for parameters also
             if caseClassSynthetics(s.owner.name) && s.owner.is(Flags.Synthetic)
@@ -211,9 +217,9 @@ abstract class PcCollector[T](
                   s.owner.owner.info.member(s.name).symbol
                 )
                   .filter(_ != NoSymbol),
-                arg.sourcePos,
+                pos,
               )
-            else (Set(s), arg.sourcePos)
+            else (Set(s), pos)
           }
         else None
         end if
@@ -489,14 +495,15 @@ abstract class PcCollector[T](
           }
           val named = args.map { arg =>
             val realName = arg.name.stripModuleClassSuffix.lastPart
+            val length = realName.toString.backticked.length()
             val sym = apply.symbol.paramSymss.flatten
               .find(_.name == realName)
             collect(
               arg,
               pos
                 .withSpan(
                   arg.span
-                    .withEnd(arg.span.start + realName.length)
+                    .withEnd(arg.span.start + length)
                     .withPoint(arg.span.start)
                 ),
               sym

presentation-compiler/test/dotty/tools/pc/tests/edit/PcPrepareRenameSuite.scala

@@ -507,3 +507,16 @@ class PcPrepareRenameSuite extends BasePcRenameSuite:
          |end extension
          |""".stripMargin
     )
+
+  @Test def `named-arg-backtick` =
+    prepare(
+      """|object Main {
+         |  def m() = {
+         |    def foo(`type`: String): String = `type`
+         |    val x = foo(
+         |      <<`ty@@pe`>> = "abc"
+         |    )
+         |  }
+         |}
+         |""".stripMargin,
+    )

presentation-compiler/test/dotty/tools/pc/tests/highlight/DocumentHighlightSuite.scala

@@ -843,6 +843,17 @@ class DocumentHighlightSuite extends BaseDocumentHighlightSuite:
          |""".stripMargin,
     )
 
+  @Test def `named-arg-backtick` =
+    check(
+        """|object Main {
+           |  def foo(<<`type`>>: String): String = <<`type`>>
+           |  val x = foo(
+           |    <<`ty@@pe`>> = "abc"
+           |  )
+           |}
+           |""".stripMargin,
+    )
+
   @Test def `enum1` =
     check(
       """|enum FooEnum:

presentation-compiler/test/dotty/tools/pc/tests/tokens/SemanticTokensSuite.scala

@@ -332,3 +332,14 @@ class SemanticTokensSuite extends BaseSemanticTokensSuite:
          |}
          |""".stripMargin
     )
+
+  @Test def `named-arg-backtick` =
+    check(
+        """|object <<Main>>/*class*/ {
+           |  def <<foo>>/*method,definition*/(<<`type`>>/*parameter,declaration,readonly*/: <<String>>/*type*/): <<String>>/*type*/ = <<`type`>>/*parameter,readonly*/
+           |  val <<x>>/*variable,definition,readonly*/ = <<foo>>/*method*/(
+           |    <<`type`>>/*parameter,readonly*/ = "abc"
+           |  )
+           |}
+          |""".stripMargin,
+    )