Revert some changes in NameBuffer

This reverts soke changes from commit d4a5515.

Use again a LinkedHashMap instead of a combination of EqHashMap and ArrayBuffer

Author: odersky

compiler/src/dotty/tools/dotc/core/tasty/NameBuffer.scala

@@ -6,7 +6,7 @@ package tasty
 import dotty.tools.tasty.TastyBuffer
 import TastyBuffer._
 
-import collection.mutable.ArrayBuffer
+import collection.mutable
 import Names.{Name, chrs, SimpleName, DerivedName, TypeName}
 import NameKinds._
 import NameOps._
@@ -16,36 +16,38 @@ import NameTags.{SIGNED, TARGETSIGNED}
 class NameBuffer extends TastyBuffer(10000) {
   import NameBuffer._
 
-  private val nameRefs = new util.EqHashMap[Name, NameRef]
-  private val nameBuf = new ArrayBuffer[Name]
+  private val nameRefs = new mutable.LinkedHashMap[Name, NameRef]
 
-  def nameIndex(name: Name): NameRef =
+  def nameIndex(name: Name): NameRef = {
     val name1 = name.toTermName
-    val ref: NameRef | Null = nameRefs.lookup(name1)
-    if ref != null then ref.uncheckedNN
-    else
-      name1 match
-        case SignedName(original, Signature(params, result), target) =>
-          nameIndex(original)
-          if !original.matchesTargetName(target) then nameIndex(target)
-          nameIndex(result)
-          params.foreach {
-            case param: TypeName =>
-              nameIndex(param)
-            case _ =>
-          }
-        case AnyQualifiedName(prefix, name) =>
-          nameIndex(prefix); nameIndex(name)
-        case AnyUniqueName(original, separator, num) =>
-          nameIndex(separator)
-          if (!original.isEmpty) nameIndex(original)
-        case DerivedName(original, _) =>
-          nameIndex(original)
-        case _ =>
-      val ref1 = NameRef(nameRefs.size)
-      nameRefs(name1) = ref1
-      nameBuf += name1
-      ref1
+    nameRefs.get(name1) match {
+      case Some(ref) =>
+        ref
+      case None =>
+        name1 match {
+          case SignedName(original, Signature(params, result), target) =>
+            nameIndex(original)
+            if !original.matchesTargetName(target) then nameIndex(target)
+            nameIndex(result)
+            params.foreach {
+              case param: TypeName =>
+                nameIndex(param)
+              case _ =>
+            }
+          case AnyQualifiedName(prefix, name) =>
+            nameIndex(prefix); nameIndex(name)
+          case AnyUniqueName(original, separator, num) =>
+            nameIndex(separator)
+            if (!original.isEmpty) nameIndex(original)
+          case DerivedName(original, _) =>
+            nameIndex(original)
+          case _ =>
+        }
+        val ref = NameRef(nameRefs.size)
+        nameRefs(name1) = ref
+        ref
+    }
+  }
 
   private inline def withLength(inline op: Unit, lengthWidth: Int = 1): Unit = {
     val lengthAddr = currentAddr
@@ -112,7 +114,7 @@ class NameBuffer extends TastyBuffer(10000) {
 
   override def assemble(): Unit = {
     var i = 0
-    for name <- nameBuf do
+    for (name, ref) <- nameRefs do
       val ref = nameRefs(name)
       assert(ref.index == i)
       i += 1