Fix 10156: Put generic number literals under a flag

compiler/src/dotty/tools/dotc/config/Feature.scala

@@ -12,6 +12,10 @@ import reporting.Message
 
 object Feature:
 
+  private val dependent = "dependent".toTermName
+  private val namedTypeArguments = "namedTypeArguments".toTermName
+  private val genericNumberLiterals = "genericNumberLiterals".toTermName
+
 /** Is `feature` enabled by by a command-line setting? The enabling setting is
    *
    *       -language:<prefix>feature
@@ -58,10 +62,13 @@ object Feature:
     enabled(nme.dynamics)
 
   def dependentEnabled(using Context) =
-    enabled(nme.dependent, defn.LanguageExperimentalModule.moduleClass)
+    enabled(dependent, defn.LanguageExperimentalModule.moduleClass)
 
   def namedTypeArgsEnabled(using Context) =
-    enabled(nme.namedTypeArguments, defn.LanguageExperimentalModule.moduleClass)
+    enabled(namedTypeArguments, defn.LanguageExperimentalModule.moduleClass)
+
+  def genericNumberLiteralsEnabled(using Context) =
+    enabled(genericNumberLiterals, defn.LanguageExperimentalModule.moduleClass)
 
   def scala2ExperimentalMacroEnabled(using Context) =
     enabled("macros".toTermName, defn.LanguageExperimentalModule.moduleClass)

compiler/src/dotty/tools/dotc/core/StdNames.scala

@@ -446,7 +446,6 @@ object StdNames {
     val definitions: N          = "definitions"
     val delayedInit: N          = "delayedInit"
     val delayedInitArg: N       = "delayedInit$body"
-    val dependent: N            = "dependent"
     val derived: N              = "derived"
     val derives: N              = "derives"
     val doubleHash: N           = "doubleHash"
@@ -528,7 +527,6 @@ object StdNames {
     val moduleClass : N         = "moduleClass"
     val name: N                 = "name"
     val nameDollar: N           = "$name"
-    val namedTypeArguments: N   = "namedTypeArguments"
     val ne: N                   = "ne"
     val newFreeTerm: N          = "newFreeTerm"
     val newFreeType: N          = "newFreeType"

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -624,7 +624,9 @@ class Typer extends Namer
           case Whole(16) => // cant parse hex literal as double
           case _         => return lit(doubleFromDigits(digits))
         }
-      else if (target.isValueType && isFullyDefined(target, ForceDegree.none)) {
+      else if genericNumberLiteralsEnabled
+          && target.isValueType && isFullyDefined(target, ForceDegree.none)
+      then
         // If expected type is defined with a FromDigits instance, use that one
         val fromDigitsCls = tree.kind match {
           case Whole(10) => defn.FromDigitsClass
@@ -645,7 +647,6 @@ class Typer extends Namer
             return typed(app, pt)
           case _ =>
         }
-      }
       // Otherwise convert to Int or Double according to digits format
       tree.kind match {
         case Whole(radix) => lit(intFromDigits(digits, radix))

docs/docs/reference/changed-features/numeric-literals.md

@@ -3,6 +3,11 @@ layout: doc-page
 title: Numeric Literals
 ---
 
+**Note**: This feature is not yet part of the Scala 3 language definition. It can be made available by a language import:
+```scala
+import scala.language.experimental.genericNumberLiterals
+```
+
 In Scala 2, numeric literals were confined to the primitive numeric types `Int`, `Long`, `Float`, and `Double`. Scala 3 allows to write numeric literals also for user defined types. Example:
 ```scala
 val x: Long = -10_000_000_000

library/src/scalaShadowing/language.scala

@@ -216,6 +216,9 @@ object language {
 
     /** Experimental support for named type arguments */
     object namedTypeArguments
+
+    /** Experimental support for generic number literals */
+    object genericNumberLiterals
   }
 
   /** Where imported, a backwards compatibility mode for Scala2 is enabled */

tests/neg-macros/BigFloat/BigFloatFromDigitsImpl_1.scala

@@ -1,4 +1,5 @@
 package test
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 import scala.quoted._
 

tests/neg-macros/BigFloat/BigFloat_1.scala

@@ -1,4 +1,5 @@
 package test
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 import scala.quoted._
 

tests/neg-macros/GenericNumLits/EvenFromDigitsImpl_1.scala

@@ -1,3 +1,4 @@
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 import scala.quoted._
 import Even._

tests/neg-macros/GenericNumLits/Even_1.scala

@@ -1,3 +1,4 @@
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 import scala.quoted._
 

tests/neg-macros/GenericNumLits/Test_2.scala

@@ -1,3 +1,4 @@
+import language.experimental.genericNumberLiterals
 object Test extends App {
 
   val e1: Even = 1234

tests/neg-with-compiler/GenericNumLits/EvenFromDigitsImpl_1.scala

@@ -1,3 +1,4 @@
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 import scala.quoted._
 import Even._

tests/neg-with-compiler/GenericNumLits/Even_1.scala

@@ -1,3 +1,4 @@
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 import scala.quoted._
 

tests/neg-with-compiler/GenericNumLits/Test_2.scala

@@ -1,3 +1,4 @@
+import language.experimental.genericNumberLiterals
 object Test extends App {
 
   val e1: Even = 1234

tests/neg/genericNumbers.scala

@@ -0,0 +1,41 @@
+import scala.util.FromDigits
+
+object Test extends App {
+
+  val x: BigInt = 13232202002020202020202 // error
+  val z: BigDecimal = 132322020020.223
+
+  case class Even(n: Int)
+
+  given FromDigits[Even] {
+    def fromDigits(digits: String): Even = {
+      val intValue = digits.toInt
+      if (intValue % 2 == 0) Even(intValue)
+      else throw FromDigits.MalformedNumber()
+    }
+  }
+
+  val e: Even = 1234 // error
+
+  try {
+    println(123: Even) // error
+  } catch {
+    case ex: FromDigits.MalformedNumber => println("malformed")
+  }
+
+  x match {
+    case 13_232_202_002_020_202_020_202 => () // error
+  }
+  (x: Any) match {
+    case 13232202002020202020202: BigInt => () // error
+  }
+  x match {
+    case 13232202002020202020202 => assert(false) // error
+    case -0xaabb12345ACF12345AC => () // error
+  }
+
+  (e: Any) match {
+    case 1234: Even => // error
+    case _: Even =>
+  }
+}

tests/run-macros/BigFloat/BigFloatFromDigitsImpl_1.scala

@@ -1,4 +1,5 @@
 package test
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 import scala.quoted._
 

tests/run-macros/BigFloat/BigFloat_1.scala

@@ -1,4 +1,5 @@
 package test
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 import scala.quoted._
 

tests/run-macros/BigFloat/Test_2.scala

@@ -1,4 +1,5 @@
 import test.BigFloat
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 object Test extends App {
 

tests/run/genericNumLits.scala

@@ -1,3 +1,4 @@
+import language.experimental.genericNumberLiterals
 import scala.util.FromDigits
 object Test extends App {