bugfix: fix workaround for wrong spans in extension method call

mtags/src/main/scala-3/scala/meta/internal/pc/MetalsInteractive.scala

@@ -277,9 +277,9 @@ object MetalsInteractive:
        *
        * val a = MyIntOut(1).un@@even
        */
-      case (a @ Apply(sel: Select, _)) :: _
-          if sel.span.isZeroExtent && sel.symbol.is(Flags.ExtensionMethod) =>
-        List((sel.symbol, a.typeOpt))
+      case (a @ ExtensionMethodCall(symbol, app)) :: _
+          if app.span.withStart(app.span.point).contains(pos.span) =>
+        List((symbol, a.typeOpt))
 
       case path @ head :: tail =>
         if head.symbol.is(Synthetic) then
@@ -345,6 +345,26 @@ object MetalsInteractive:
     }
   end ApplySelect
 
+  object ExtensionMethodCallSymbol:
+    def unapply(tree: Tree)(using Context): Option[(Ident | Select)] =
+      tree match
+        case tree: (Ident | Select) if tree.symbol.is(Flags.ExtensionMethod) =>
+          Some(tree)
+        case TypeApply(tree: (Ident | Select), _)
+            if tree.symbol.is(Flags.ExtensionMethod) =>
+          Some(tree)
+        case _ => None
+  end ExtensionMethodCallSymbol
+
+  object ExtensionMethodCall:
+    def unapply(tree: Tree)(using Context): Option[(Symbol, Apply)] =
+      tree match
+        case app @ Apply(ExtensionMethodCallSymbol(tree), _) =>
+          Some((tree.symbol, app))
+        case Apply(tree, _) => unapply(tree)
+        case _ => None
+  end ExtensionMethodCall
+
   object TreeApply:
     def unapply(tree: Tree): Option[(Tree, List[Tree])] =
       tree match

mtags/src/main/scala-3/scala/meta/internal/pc/PcCollector.scala

@@ -6,6 +6,8 @@ import scala.meta as m
 
 import scala.meta.internal.metals.CompilerOffsetParams
 import scala.meta.internal.mtags.MtagsEnrichments.*
+import scala.meta.internal.pc.MetalsInteractive.ExtensionMethodCall
+import scala.meta.internal.pc.MetalsInteractive.ExtensionMethodCallSymbol
 import scala.meta.pc.OffsetParams
 import scala.meta.pc.VirtualFileParams
 
@@ -250,10 +252,10 @@ abstract class PcCollector[T](
        *
        * val a = MyIntOut(1).<<un@@even>>
        */
-      case (a @ Apply(sel: Select, _)) :: _
-          if sel.span.isZeroExtent && sel.symbol.is(Flags.ExtensionMethod) =>
-        val span = a.span.withStart(a.span.point)
-        Some(symbolAlternatives(sel.symbol), pos.withSpan(span))
+      case ExtensionMethodCall(sym, app) :: _
+          if app.span.withStart(app.span.point).contains(pos.span) =>
+        val span = app.span.withStart(app.span.point)
+        Some(symbolAlternatives(sym), pos.withSpan(span))
       case _ => None
 
     sought match
@@ -424,7 +426,11 @@ abstract class PcCollector[T](
          * All indentifiers such as:
          * val a = <<b>>
          */
-        case ident: Ident if ident.span.isCorrect && filter(ident) =>
+        case ident: Ident
+            if ident.span.isCorrect && filter(ident) && !isExtensionMethodCall(
+              parent,
+              ident.symbol,
+            ) =>
           // symbols will differ for params in different ext methods, but source pos will be the same
           if soughtFilter(_.sourcePos == ident.symbol.sourcePos)
           then
@@ -468,15 +474,14 @@ abstract class PcCollector[T](
          *
          * val a = MyIntOut(1).<<un@@even>>
          */
-        case sel: Select
-            if sel.span.isZeroExtent && sel.symbol.is(Flags.ExtensionMethod) =>
+        case ExtensionMethodCallSymbol(tree) =>
           parent match
             case Some(a: Apply) =>
               val span = a.span.withStart(a.span.point)
-              val amendedSelect = sel.withSpan(span)
-              if filter(amendedSelect) then
+              val amendedTree = tree.withSpan(span)
+              if filter(amendedTree) then
                 occurences + collect(
-                  amendedSelect,
+                  amendedTree,
                   pos.withSpan(span),
                 )
               else occurences
@@ -639,6 +644,16 @@ abstract class PcCollector[T](
     tree match
       case sel: Select => sel.sourcePos.withSpan(selectNameSpan(sel))
       case _ => tree.sourcePos
+
+  /**
+   * Those have wrong spans and we special case for them.
+   */
+  private def isExtensionMethodCall(parent: Option[Tree], symbol: Symbol) =
+    symbol.is(Flags.ExtensionMethod) && parent.exists {
+      case _: TypeApply | _: Apply => true
+      case _ => false
+    }
+
 end PcCollector
 
 object PcCollector:

tests/cross/src/test/scala/tests/highlight/Scala3DocumentHighlightSuite.scala

@@ -339,4 +339,50 @@ class Scala3DocumentHighlightSuite extends BaseDocumentHighlightSuite {
        |""".stripMargin
   )
 
+  check(
+    "i5921-1",
+    """|object Logarithms:
+       |  opaque type Logarithm = Double
+       |  extension [K](vmap: Logarithm)
+       |    def <<multiply>>(k: Logarithm): Logarithm = ???
+       |
+       |object Test:
+       |  val in: Logarithms.Logarithm = ???
+       |  in.<<multi@@ply>>(in)
+       |""".stripMargin
+  )
+
+  check(
+    "i5921-2",
+    """|object Logarithms:
+       |  opaque type Logarithm = Double
+       |  extension [K](vmap: Logarithm)
+       |    def <<mu@@ltiply>>(k: Logarithm): Logarithm = ???
+       |
+       |object Test:
+       |  val in: Logarithms.Logarithm = ???
+       |  in.<<multiply>>(in)
+       |""".stripMargin
+  )
+
+  check(
+    "i5921-3",
+    """|object Logarithms:
+       |  opaque type Logarithm = Double
+       |  extension [K](vmap: Logarithm)
+       |    def <<multiply>>(k: Logarithm): Logarithm = ???
+       |  (2.0).<<mult@@iply>>(1.0)
+       |""".stripMargin
+  )
+
+  check(
+    "i5921-4",
+    """|object Logarithms:
+       |  opaque type Logarithm = Double
+       |  extension [K](vmap: Logarithm)
+       |    def <<mult@@iply>>(k: Logarithm): Logarithm = ???
+       |  (2.0).<<multiply>>(1.0)
+       |""".stripMargin
+  )
+
 }

tests/cross/src/test/scala/tests/hover/HoverScala3TypeSuite.scala

@@ -376,4 +376,18 @@ class HoverScala3TypeSuite extends BaseHoverSuite {
     """|extension (i: MyIntOut) def uneven: Boolean
        |""".stripMargin.hover
   )
+
+  check(
+    "i5921",
+    """|object Logarithms:
+       |  trait Logarithm
+       |  extension [K](vmap: Logarithm)
+       |    def multiply(k: Logarithm): Logarithm = ???
+       |
+       |object Test:
+       |  val in: Logarithms.Logarithm = ???
+       |  in.multi@@ply(in)
+       |""".stripMargin,
+    "extension [K](vmap: Logarithm) def multiply(k: Logarithm): Logarithm".hover
+  )
 }

tests/cross/src/test/scala/tests/pc/PcDefinitionSuite.scala

@@ -560,7 +560,7 @@ class PcDefinitionSuite extends BasePcDefinitionSuite {
   )
 
   check(
-    "i5630".tag(IgnoreScala2.and(IgnoreForScala3CompilerPC)),
+    "i5630".tag(IgnoreScala2),
     """|class MyIntOut(val value: Int)
        |object MyIntOut:
        |  extension (i: MyIntOut) def <<uneven>> = i.value % 2 == 1
@@ -569,4 +569,38 @@ class PcDefinitionSuite extends BasePcDefinitionSuite {
        |""".stripMargin
   )
 
+  check(
+    "i5921".tag(IgnoreScala2),
+    """|object Logarithms:
+       |  opaque type Logarithm = Double
+       |  extension [K](vmap: Logarithm)
+       |    def <<multiply>>(k: Logarithm): Logarithm = ???
+       |
+       |object Test:
+       |  val in: Logarithms.Logarithm = ???
+       |  in.multi@@ply(in)
+       |""".stripMargin
+  )
+
+  check(
+    "i5921-1".tag(IgnoreScala2),
+    """|object Logarithms:
+       |  opaque type Logarithm = Double
+       |  extension [K](vmap: Logarithm)
+       |    def <<multiply>>(k: Logarithm): Logarithm = ???
+       |  (2.0).mult@@iply(1.0)
+       |""".stripMargin
+  )
+
+  check(
+    "i5921-2".tag(IgnoreScala2),
+    """|object Logarithms:
+       |  opaque type Logarithm = Double
+       |  extension [K](vmap: Logarithm)
+       |    def multiply(k: Logarithm): Logarithm = ???
+       |  val <<vv>> = 1.0
+       |  (2.0).multiply(v@@v)
+       |""".stripMargin
+  )
+
 }