Move LiftExprOps to quoted package

To use `import scala.quotes._` to import `toExpr` extension

Author: nicolasstucki

docs/docs/reference/principled-meta-programming.md

@@ -527,17 +527,17 @@ work since replacing `n` by `’n` in the clause would not be phase
 correct.
 
 What happens instead "under the hood" is an extension method `toExpr` is added: `n.toExpr`
-is expanded to `new scala.quoted.Liftable.LiftExprOps(n).toExpr`. The `toExpr` extension
+is expanded to `new scala.quoted.LiftExprOps(n).toExpr`. The `toExpr` extension
 is defined in the companion object of class `Liftable` as follows:
 
-    object Liftable {
+    package object quoted {
       implicit class LiftExprOps[T](val x: T) extends AnyVal {
         def toExpr(implicit ev: Liftable[T]): Expr[T] = ev.toExpr(x)
       }
     }
 
 The extension says that values of types implementing the `Liftable` type class can be
-converted ("lifted") to `Expr` values using `toExpr` when `Liftable._` is imported.
+converted ("lifted") to `Expr` values using `toExpr` when `scala.quoted._` is imported.
 Dotty comes with instance definitions of `Liftable` for
 several types including `Boolean`, `String`, and all primitive number
 types. For example, `Int` values can be converted to `Expr[Int]`

library/src/scala/quoted/Liftable.scala

@@ -15,11 +15,6 @@ abstract class Liftable[T] {
  *  gives an alternative implementation using just the basic staging system.
  */
 object Liftable {
-
-  implicit class LiftExprOps[T](val x: T) extends AnyVal {
-    def toExpr(implicit ev: Liftable[T]): Expr[T] = ev.toExpr(x)
-  }
-
   implicit def BooleanIsLiftable: Liftable[Boolean] = (x: Boolean) => new ValueExpr(x)
   implicit def ByteLiftable: Liftable[Byte] = (x: Byte) => new ValueExpr(x)
   implicit def CharIsLiftable: Liftable[Char] = (x: Char) => new ValueExpr(x)

library/src/scala/quoted/package.scala

@@ -0,0 +1,9 @@
+package scala
+
+package object quoted {
+
+  implicit class LiftExprOps[T](val x: T) extends AnyVal {
+    def toExpr(implicit ev: Liftable[T]): Expr[T] = ev.toExpr(x)
+  }
+
+}

tests/pos/i3916/Macro_1.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 class FInterpolatorHelper(val sc: StringContext) extends AnyVal {
   inline def ff(arg1: Any): String = ~FInterpolation.fInterpolation(sc, Seq('(arg1)))

tests/pos/quote-0.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/pos/quote-interpolator-core/quoted_1.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 // This test checks the correct interpretation of the inlined value class
 

tests/pos/quote-lift.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 object Test {
 

tests/pos/quote-liftable.scala

@@ -1,7 +1,5 @@
 import scala.quoted._
 
-import scala.quoted.Liftable._
-
 object Test {
 
   implicit def IntIsLiftable: Liftable[Int] = new {

tests/run-with-compiler/i4044b.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/run-with-compiler/quote-lib.scala

@@ -1,6 +1,5 @@
 
 import scala.quoted._
-import scala.quoted.Liftable._
 import dotty.tools.dotc.quoted.Toolbox._
 
 import liftable.Units._
@@ -43,7 +42,6 @@ object Test {
 
 package liftable {
   import scala.quoted.Liftable
-  import scala.quoted.Liftable._
   import scala.reflect.ClassTag
 
   object Exprs {

tests/run-with-compiler/quote-run-constants-extract-1.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/run-with-compiler/quote-run-constants-extract-2.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/run-with-compiler/quote-run-constants-extract-3.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/run-with-compiler/quote-run-constants-extract-4.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/run-with-compiler/quote-run-constants-extract-5.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/run-with-compiler/quote-run-constants-extract-6.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/run-with-compiler/quote-run-constants.scala

@@ -2,7 +2,6 @@
 import dotty.tools.dotc.quoted.Toolbox._
 
 import scala.quoted._
-import scala.quoted.Liftable._
 
 object Test {
   def main(args: Array[String]): Unit = {

tests/run-with-compiler/quote-run-staged-interpreter.scala

@@ -1,5 +1,4 @@
 import scala.quoted._
-import scala.quoted.Liftable._
 
 import dotty.tools.dotc.quoted.Toolbox._
 

tests/run-with-compiler/quote-show-blocks-raw.scala

@@ -2,7 +2,6 @@
 import dotty.tools.dotc.quoted.Toolbox._
 
 import scala.quoted._
-import scala.quoted.Liftable._
 
 object Test {
   def main(args: Array[String]): Unit = {

tests/run-with-compiler/quote-show-blocks.scala

@@ -2,7 +2,6 @@
 import dotty.tools.dotc.quoted.Toolbox._
 
 import scala.quoted._
-import scala.quoted.Liftable._
 
 object Test {
   def main(args: Array[String]): Unit = {

tests/run/quote-splice-interpret-1/Macro_1.scala

@@ -1,7 +1,6 @@
 import dotty.tools.dotc.ast.Trees.Import
 
 import scala.quoted._
-import scala.quoted.Liftable._
 
 object Macros {
   sealed trait Nat