Add quoted.Liftable[BigInt] to the stdlib

Author: nicolasstucki

library/src/scala/quoted/Liftable.scala

@@ -232,4 +232,12 @@ object Liftable {
     }
   }
 
+  given as Liftable[BigInt] = new Liftable[BigInt] {
+    def toExpr(x: BigInt): given QuoteContext => Expr[BigInt] = {
+      lazy val xInt: Int = x.intValue()
+      if (x.isValidInt && -1024 <= xInt && xInt < 1024) '{ BigInt(${xInt.toExpr}) } // Cached BigInt
+      else '{ BigInt(${x.toString(Character.MAX_RADIX).toExpr}, ${Character.MAX_RADIX.toExpr}) } // Compact string BigInt
+    }
+  }
+
 }

tests/run-with-compiler/quote-lift-BigInt.check

@@ -0,0 +1 @@
+(2,1005849025843905834908593485984390583429058574925)

tests/run-with-compiler/quote-lift-BigInt.scala

@@ -0,0 +1,9 @@
+import scala.quoted._
+object Test {
+  implicit val toolbox: scala.quoted.Toolbox = scala.quoted.Toolbox.make(getClass.getClassLoader)
+  def main(args: Array[String]): Unit = println(run {
+    val a = BigInt(2).toExpr
+    val b = BigInt("1005849025843905834908593485984390583429058574925").toExpr
+    '{ ($a, $b) }
+  })
+}