fix: map name position to desugared version of named context bound

Author: kasiaMarek

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -272,18 +272,20 @@ object desugar {
       case ContextBounds(tbounds, ctxbounds) =>
         val isMember = evidenceFlags.isAllOf(DeferredGivenFlags)
         for bound <- ctxbounds do
-          val evidenceName = bound match
+          val (evidenceName, spanPoint) = bound match
             case ContextBoundTypeTree(_, _, ownName) if !ownName.isEmpty =>
-              ownName // if there is an explicitly given name, use it.
+              val realName = ownName.stripModuleClassSuffix.lastPart
+              (ownName, bound.span.end - realName.length) // if there is an explicitly given name, use it.
             case _ =>
               if Config.nameSingleContextBounds
                 && !isMember
                 && ctxbounds.tail.isEmpty
                 && Feature.enabled(Feature.modularity)
-              then tdef.name.toTermName
-              else freshName(bound)
+              then (tdef.name.toTermName, bound.span.point)
+              else (freshName(bound), bound.span.point)
           evidenceNames += evidenceName
-          val evidenceParam = ValDef(evidenceName, bound, EmptyTree).withFlags(evidenceFlags)
+          val evidenceParam =
+            ValDef(evidenceName, bound, EmptyTree).withFlags(evidenceFlags).withSpan(bound.span.withPoint(spanPoint))
           evidenceParam.pushAttachment(ContextBoundParam, ())
           evidenceBuf += evidenceParam
         tbounds

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -2265,7 +2265,8 @@ object Parsers {
           in.nextToken()
           ident()
         else EmptyTermName
-      ContextBoundTypeTree(t, pname, ownName)
+      val newSpan = t.span.withPoint(t.span.end).withEnd(in.lastOffset)
+      ContextBoundTypeTree(t, pname, ownName).withSpan(newSpan)
 
     /** ContextBounds     ::= ContextBound [`:` ContextBounds]
      *                      | `{` ContextBound {`,` ContextBound} `}`

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -2466,7 +2466,7 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
   def typedContextBoundTypeTree(tree: untpd.ContextBoundTypeTree)(using Context): Tree =
     val tycon = typedType(tree.tycon)
     def spliced(tree: Tree) = untpd.TypedSplice(tree)
-    val tparam = untpd.Ident(tree.paramName).withSpan(tree.span)
+    val tparam = untpd.Ident(tree.paramName).withSpan(tree.span.withEnd(tree.span.point))
     if tycon.tpe.typeParams.nonEmpty then
       val tycon0 = tycon.withType(tycon.tpe.etaCollapse)
       typed(untpd.AppliedTypeTree(spliced(tycon0), tparam :: Nil))

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

@@ -238,3 +238,27 @@ class HoverDefnSuite extends BaseHoverSuite:
          |""".stripMargin,
       "val foo: Int".hover
     )
+
+  @Test def `i22335` =
+    check(
+      """|def fromInt[T: Numeric as n@@um](t: Int): T = num.fromInt(t)
+         |""".stripMargin,
+      """|num: Numeric[T]
+         |""".stripMargin.hover
+    )
+
+  @Test def `i22335-2` =
+    check(
+      """|def showMax[X : {Numeric as nu@@m, Ordered as ord}](x: X, y: X): String = ???
+         |""".stripMargin,
+      """|num: Numeric[X]
+          |""".stripMargin.hover
+    )
+
+  @Test def `i22335-3` =
+    check(
+      """|def showMax[X : {Nu@@meric as num, Ordered as ord}](x: X, y: X): String = ???
+         |""".stripMargin,
+      """|type Numeric: Numeric
+         |""".stripMargin.hover
+    )