any2stringadd is ineligible under -Xsource:3-cross

Author: Som Snytt

src/compiler/scala/tools/nsc/typechecker/Implicits.scala

@@ -1040,7 +1040,9 @@ trait Implicits extends splain.SplainData {
 
       private def isIneligible(info: ImplicitInfo) = (
            info.isCyclicOrErroneous
-        || isView && ((info.sym eq Predef_conforms) || (info.sym eq SubType_refl)) // as implicit conversions, Predef.$conforms and <:<.refl are no-op, so exclude them
+        || isView && ((info.sym eq Predef_conforms) || (info.sym eq SubType_refl) ||
+              currentRun.sourceFeatures.any2StringAdd && (info.sym eq currentRun.runDefinitions.Predef_any2stringaddMethod)
+          ) // as implicit conversions, Predef.$conforms and <:<.refl are no-op, so exclude them
         || (!context.macrosEnabled && info.sym.isTermMacro)
       )
 

test/files/run/t13004.check

@@ -0,0 +1,4 @@
+t13004.scala:12: applied implicit conversion from Money to ?{def + : ?} = implicit def MoneySyntax(self: Money): Money.MoneySyntax
+    Money(3.14) + Money(1.7)
+         ^
+Money(4.84)

test/files/run/t13004.scala

@@ -0,0 +1,14 @@
+//> using options -Xsource:3 -Xsource-features:any2stringadd -Vimplicit-conversions
+
+case class Money(value: Double)
+object Money {
+  implicit class MoneySyntax(private val self: Money)  extends AnyVal {
+    def +(other: Money): Money = Money(self.value + other.value)
+  }
+}
+
+object Test extends App {
+  println {
+    Money(3.14) + Money(1.7)
+  }
+}