Apply suggested changes

- Change Tasty -> TASTy as language alias
- Override backendPhases instead of phases
- Fix inefficient string concat in StringBuilder call
- Fix printNat using Yellow directly instead of treeColor preventing override

Author: Tobias Bordenca

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

@@ -23,7 +23,7 @@ class TastyPrinter(bytes: Array[Byte])(implicit ctx: Context) {
   def printNames(): Unit =
     for ((name, idx) <- nameAtRef.contents.zipWithIndex) {
       val index = nameColor("%4d".format(idx))
-      sb.append(index + ": " + nameToString(name) + "\n")
+      sb.append(index).append(": ").append(nameToString(name)).append("\n")
     }
 
   def printContents(): String = {
@@ -60,15 +60,15 @@ class TastyPrinter(bytes: Array[Byte])(implicit ctx: Context) {
         val length = treeColor("%5d".format(index(currentAddr) - index(startAddr)))
         sb.append(s"\n $length:" + " " * indent)
       }
-      def printNat() = sb.append(Yellow(" " + readNat()).show)
+      def printNat() = sb.append(treeColor(" " + readNat()))
       def printName() = {
         val idx = readNat()
         sb.append(nameColor(" " + idx + " [" + nameRefToString(NameRef(idx)) + "]"))
       }
       def printTree(): Unit = {
         newLine()
         val tag = readByte()
-        sb.append(" ");sb.append(astTagToString(tag))
+        sb.append(" ").append(astTagToString(tag))
         indent += 2
         if (tag >= firstLengthTreeTag) {
           val len = readNat()

compiler/src/dotty/tools/dotc/decompiler/PartialTASTYDecompiler.scala

@@ -7,6 +7,5 @@ import dotty.tools.dotc.core.Phases.Phase
   * on the CompilationUnits
  */
 class PartialTASTYDecompiler extends TASTYDecompiler {
-  override def phases: List[List[Phase]] =
-    frontendPhases ::: picklerPhases ::: transformPhases
+  override protected def backendPhases: List[List[Phase]] = Nil
 }

vscode-dotty/package.json

@@ -45,7 +45,7 @@
           ".tasty"
         ],
         "aliases": [
-          "Tasty"
+          "TASTy"
         ]
       }
     ],