Mode internal StringContext.f implementation to dotty package

Author: nicolasstucki

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

@@ -637,7 +637,7 @@ class Definitions {
     lazy val StringContextModule_applyR: TermRef = StringContextModule.requiredMethodRef(nme.apply)
     def StringContextModule_apply(implicit ctx: Context): Symbol = StringContextModule_applyR.symbol
 
-  lazy val InternalStringContextModuleR: TermRef = ctx.requiredModuleRef("scala.internal.StringContext")
+  lazy val InternalStringContextModuleR: TermRef = ctx.requiredModuleRef("dotty.internal.StringContext")
   def InternalStringContextModule(implicit ctx: Context): Symbol = InternalStringContextModuleR.termSymbol
     lazy val InternalStringContextModule_fR: TermRef = InternalStringContextModule.requiredMethodRef(nme.f)
     def InternalStringContextModule_f(implicit ctx: Context): Symbol = InternalStringContextModule_fR.symbol

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

@@ -2755,9 +2755,14 @@ class Typer extends Namer
       }
       else if (tree.symbol.isScala2Macro) {
         if (ctx.settings.XignoreScala2Macros.value) {
-          ctx.warning("Scala 2 macro cannot be used in Dotty. See http://dotty.epfl.ch/docs/reference/dropped-features/macros.html", tree.sourcePos)
+          ctx.warning("Scala 2 macro cannot be used in Dotty, this call will crash at runtime. See http://dotty.epfl.ch/docs/reference/dropped-features/macros.html", tree.sourcePos)
           tree
         } else if (tree.symbol eq defn.StringContext_f) {
+          // As scala.StringContext.f is defined in the standard library which
+          // we currently do not bootstrap we cannot implement the macro the library.
+          // To overcome the current limitation we intercept the call and rewrite it into
+          // a call to dotty.internal.StringContext.f which we can implement using the new macros.
+          // As the macro is implemented in the bootstrapped library, it can only be used from the bootstrapped compiler.
           val Apply(TypeApply(Select(sc, _), _), args) = tree
           val newCall = ref(defn.InternalStringContextModule_f).appliedTo(sc).appliedToArgs(args)
           Inliner.inlineCall(newCall, pt)

library/src-bootstrapped/scala/internal/StringContext.scala renamed to library/src-bootstrapped/dotty/internal/StringContext.scala

@@ -1,9 +1,10 @@
-package scala.internal
+package dotty.internal
 
 import scala.quoted._
 
 object StringContext {
 
+  /** Implemetation of scala.StringContext.f used in Dotty while the standard library is still not bootstrapped */
   inline def f(sc: => scala.StringContext)(args: Any*): String = ${ fImpl('sc, 'args) }
 
   private def fImpl(sc: Expr[StringContext], args: Expr[Seq[Any]]): Expr[String] = {

library/src-non-bootstrapped/scala/internal/StringContext.scala renamed to library/src-non-bootstrapped/dotty/internal/StringContext.scala

@@ -1,4 +1,4 @@
-package scala.internal
+package dotty.internal
 
 object StringContext {