From d5840fc7e339f13fb0c8cc8fe027cd5b79ac9609 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Wed, 27 Mar 2019 15:23:01 +0100
Subject: [PATCH 1/8] Fix #6150: Emit error when calling Scala 2 macro

---
 compiler/src/dotty/tools/dotc/profile/Profiler.scala | 2 +-
 compiler/src/dotty/tools/dotc/typer/Typer.scala      | 4 ++++
 compiler/test/dotty/tools/backend/jvm/AsmNode.scala  | 4 ++--
 project/Build.scala                                  | 6 ++++++
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/profile/Profiler.scala b/compiler/src/dotty/tools/dotc/profile/Profiler.scala
index ecb9696a7fd5..69d493b78f3f 100644
--- a/compiler/src/dotty/tools/dotc/profile/Profiler.scala
+++ b/compiler/src/dotty/tools/dotc/profile/Profiler.scala
@@ -228,7 +228,7 @@ object ConsoleProfileReporter extends ProfileReporter {
   }
 
   override def reportGc(data: GcEventData): Unit = {
-    println(f"Profiler GC reported ${data.gcEndMillis - data.gcStartMillis}ms")
+    println(s"Profiler GC reported ${data.gcEndMillis - data.gcStartMillis}ms")
   }
 }
 
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 1c81ef0ec665..abbe4e6d599e 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -2753,6 +2753,10 @@ class Typer extends Namer
         tree.tpe <:< wildApprox(pt)
         readaptSimplified(Inliner.inlineCall(tree, pt))
       }
+      else if (tree.symbol.is(Macro, butNot = Inline)) {
+        ctx.error("Scala 2 macro cannot be used in Dotty. See http://dotty.epfl.ch/docs/reference/dropped-features/macros.html", tree.sourcePos)
+        tree
+      }
       else if (tree.tpe <:< pt) {
         if (pt.hasAnnotation(defn.InlineParamAnnot))
           checkInlineConformant(tree, isFinal = false, "argument to inline parameter")
diff --git a/compiler/test/dotty/tools/backend/jvm/AsmNode.scala b/compiler/test/dotty/tools/backend/jvm/AsmNode.scala
index ac3f34258d67..1100c9054b4d 100644
--- a/compiler/test/dotty/tools/backend/jvm/AsmNode.scala
+++ b/compiler/test/dotty/tools/backend/jvm/AsmNode.scala
@@ -15,8 +15,8 @@ sealed trait AsmNode[+T] {
   def attrs: List[Attribute]
   def visibleAnnotations: List[AnnotationNode]
   def invisibleAnnotations: List[AnnotationNode]
-  def characteristics = f"$name%15s $desc%-30s$accessString$sigString"
-  def erasedCharacteristics = f"$name%15s $desc%-30s$accessString"
+  def characteristics = "%15s %-30s%s%s".format(name, desc, accessString, sigString)
+  def erasedCharacteristics = "%15s %-30s%s".format(name, desc, accessString)
 
   private def accessString     = if (access == 0) "" else " " + Modifier.toString(access)
   private def sigString        = if (signature == null) "" else " " + signature
diff --git a/project/Build.scala b/project/Build.scala
index 429bab53705d..75b2ce43322f 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -568,6 +568,12 @@ object Build {
             IO.delete(trgDir)
           IO.createDirectory(trgDir)
           IO.unzip(scalaJSIRSourcesJar, trgDir)
+
+          // Remove f interpolator macro call to avoid its expansion while compiling the compiler and the implementation of the f macro
+          val utilsFile = trgDir / "org/scalajs/ir/Utils.scala"
+          val patchedSource = IO.read(utilsFile).replace("""f"\\u$c%04x"""", """"\\u%04x".format(c)""")
+          IO.write(utilsFile, patchedSource)
+
           (trgDir ** "*.scala").get.toSet
         } (Set(scalaJSIRSourcesJar)).toSeq
       }.taskValue,

From 70de4ec13fa72ca0576fecbbf725b9b9622bd9c2 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Wed, 27 Mar 2019 18:16:59 +0100
Subject: [PATCH 2/8] Intrinsify f interpolator

---
 .../src/dotty/tools/dotc/core/Definitions.scala   |  7 +++++++
 compiler/src/dotty/tools/dotc/typer/Typer.scala   | 10 ++++++++--
 .../scala/internal/StringContext.scala            | 15 +++++++++++++++
 .../scala/internal/StringContext.scala            |  8 ++++++++
 tests/run-with-compiler/f-interpolator.check      |  2 ++
 tests/run-with-compiler/f-interpolator.scala      |  7 +++++++
 6 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 library/src-bootstrapped/scala/internal/StringContext.scala
 create mode 100644 library/src-non-bootstrapped/scala/internal/StringContext.scala
 create mode 100644 tests/run-with-compiler/f-interpolator.check
 create mode 100644 tests/run-with-compiler/f-interpolator.scala

diff --git a/compiler/src/dotty/tools/dotc/core/Definitions.scala b/compiler/src/dotty/tools/dotc/core/Definitions.scala
index 5c1c678dc02c..d423c676e4b8 100644
--- a/compiler/src/dotty/tools/dotc/core/Definitions.scala
+++ b/compiler/src/dotty/tools/dotc/core/Definitions.scala
@@ -631,10 +631,17 @@ class Definitions {
     def StringContextS(implicit ctx: Context): Symbol = StringContextSR.symbol
     lazy val StringContextRawR: TermRef = StringContextClass.requiredMethodRef(nme.raw_)
     def StringContextRaw(implicit ctx: Context): Symbol = StringContextRawR.symbol
+    lazy val StringContext_fR: TermRef = StringContextClass.requiredMethodRef(nme.f)
+    def StringContext_f(implicit ctx: Context): Symbol = StringContext_fR.symbol
   def StringContextModule(implicit ctx: Context): Symbol = StringContextClass.companionModule
     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")
+  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
+
   lazy val PartialFunctionType: TypeRef         = ctx.requiredClassRef("scala.PartialFunction")
   def PartialFunctionClass(implicit ctx: Context): ClassSymbol = PartialFunctionType.symbol.asClass
     lazy val PartialFunction_isDefinedAtR: TermRef = PartialFunctionClass.requiredMethodRef(nme.isDefinedAt)
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index abbe4e6d599e..0b3da15b03f7 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -2754,8 +2754,14 @@ class Typer extends Namer
         readaptSimplified(Inliner.inlineCall(tree, pt))
       }
       else if (tree.symbol.is(Macro, butNot = Inline)) {
-        ctx.error("Scala 2 macro cannot be used in Dotty. See http://dotty.epfl.ch/docs/reference/dropped-features/macros.html", tree.sourcePos)
-        tree
+        if (tree.symbol eq defn.StringContext_f) {
+          val Apply(TypeApply(Select(sc, _), _), args) = tree
+          val newCall = ref(defn.InternalStringContextModule_f).appliedTo(sc).appliedToArgs(args)
+          Inliner.inlineCall(newCall, pt)
+        } else {
+          ctx.error("Scala 2 macro cannot be used in Dotty. See http://dotty.epfl.ch/docs/reference/dropped-features/macros.html", tree.sourcePos)
+          tree
+        }
       }
       else if (tree.tpe <:< pt) {
         if (pt.hasAnnotation(defn.InlineParamAnnot))
diff --git a/library/src-bootstrapped/scala/internal/StringContext.scala b/library/src-bootstrapped/scala/internal/StringContext.scala
new file mode 100644
index 000000000000..bf8818e871e2
--- /dev/null
+++ b/library/src-bootstrapped/scala/internal/StringContext.scala
@@ -0,0 +1,15 @@
+package scala.internal
+
+import scala.quoted._
+
+object StringContext {
+
+  inline def f(sc: => scala.StringContext)(args: Any*): String = ${ fImpl('sc, 'args) }
+
+  private def fImpl(sc: Expr[StringContext], args: Expr[Seq[Any]]): Expr[String] = {
+    // TODO implement f interpolation checks and addapt sc.parts
+    //   See https://github.com/alemannosara/f-interpolators-in-Dotty-macros
+    '{ $sc.parts.mkString.format($args: _*) }
+  }
+
+}
diff --git a/library/src-non-bootstrapped/scala/internal/StringContext.scala b/library/src-non-bootstrapped/scala/internal/StringContext.scala
new file mode 100644
index 000000000000..b7500e7eea1b
--- /dev/null
+++ b/library/src-non-bootstrapped/scala/internal/StringContext.scala
@@ -0,0 +1,8 @@
+package scala.internal
+
+object StringContext {
+
+  @forceInline def f(sc: => scala.StringContext)(args: Any*): String =
+    throw new Exception("non-boostrapped library")
+
+}
diff --git a/tests/run-with-compiler/f-interpolator.check b/tests/run-with-compiler/f-interpolator.check
new file mode 100644
index 000000000000..6a350be32166
--- /dev/null
+++ b/tests/run-with-compiler/f-interpolator.check
@@ -0,0 +1,2 @@
+abc
+Hello world
diff --git a/tests/run-with-compiler/f-interpolator.scala b/tests/run-with-compiler/f-interpolator.scala
new file mode 100644
index 000000000000..385a31d72004
--- /dev/null
+++ b/tests/run-with-compiler/f-interpolator.scala
@@ -0,0 +1,7 @@
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    println(f"abc")
+    println(f"Hello ${"world"}%s")
+  }
+}
\ No newline at end of file

From 48b66ef6d14b28a5526e7d83bacacf89239a54af Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Wed, 27 Mar 2019 20:32:57 +0100
Subject: [PATCH 3/8] Avoid failing with macros in the community build

---
 community-build/community-projects/ScalaPB               | 2 +-
 community-build/community-projects/scalatest             | 2 +-
 compiler/src/dotty/tools/dotc/config/ScalaSettings.scala | 1 +
 compiler/src/dotty/tools/dotc/typer/Typer.scala          | 5 ++++-
 4 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/community-build/community-projects/ScalaPB b/community-build/community-projects/ScalaPB
index 329e6d037627..79ecc8db710e 160000
--- a/community-build/community-projects/ScalaPB
+++ b/community-build/community-projects/ScalaPB
@@ -1 +1 @@
-Subproject commit 329e6d03762799d7c565859eb8df32ea16814a2e
+Subproject commit 79ecc8db710e53f07ea12d1dfef80993bbd62e96
diff --git a/community-build/community-projects/scalatest b/community-build/community-projects/scalatest
index 8e87031d1674..8e59b4800d4f 160000
--- a/community-build/community-projects/scalatest
+++ b/community-build/community-projects/scalatest
@@ -1 +1 @@
-Subproject commit 8e87031d16741022bac42d2562961ac9092ca91a
+Subproject commit 8e59b4800d4fb247e78a82314afec2ea233325e8
diff --git a/compiler/src/dotty/tools/dotc/config/ScalaSettings.scala b/compiler/src/dotty/tools/dotc/config/ScalaSettings.scala
index 5202666b5414..b3b4b55d19fb 100644
--- a/compiler/src/dotty/tools/dotc/config/ScalaSettings.scala
+++ b/compiler/src/dotty/tools/dotc/config/ScalaSettings.scala
@@ -77,6 +77,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val XreplLineWidth: Setting[Int] = IntSetting("-Xrepl-line-width", "Maximal number of columns per line for REPL output", 390)
   val XfatalWarnings: Setting[Boolean] = BooleanSetting("-Xfatal-warnings", "Fail the compilation if there are any warnings.")
   val XverifySignatures: Setting[Boolean] = BooleanSetting("-Xverify-signatures", "Verify generic signatures in generated bytecode.")
+  val XignoreScala2Macros: Setting[Boolean] = BooleanSetting("-Xignore-scala2-macros", "Ignore errors when compiling code that calls Scala2 macros, these will fail at runtime.")
 
   val XmixinForceForwarders = ChoiceSetting(
     name    = "-Xmixin-force-forwarders",
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 0b3da15b03f7..c00f0a9c9544 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -2754,7 +2754,10 @@ class Typer extends Namer
         readaptSimplified(Inliner.inlineCall(tree, pt))
       }
       else if (tree.symbol.is(Macro, butNot = Inline)) {
-        if (tree.symbol eq defn.StringContext_f) {
+        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)
+          tree
+        } else if (tree.symbol eq defn.StringContext_f) {
           val Apply(TypeApply(Select(sc, _), _), args) = tree
           val newCall = ref(defn.InternalStringContextModule_f).appliedTo(sc).appliedToArgs(args)
           Inliner.inlineCall(newCall, pt)

From 89070aebc7df4ec5e3c374711cd5c365305bdcac Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Thu, 28 Mar 2019 09:06:25 +0100
Subject: [PATCH 4/8] Fix implementation of f interpolation macro

---
 .../scala/internal/StringContext.scala                 | 10 ++++++++--
 tests/run-with-compiler/f-interpolator.check           |  3 ++-
 tests/run-with-compiler/f-interpolator.scala           |  5 +++--
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/library/src-bootstrapped/scala/internal/StringContext.scala b/library/src-bootstrapped/scala/internal/StringContext.scala
index bf8818e871e2..a10ba805ea41 100644
--- a/library/src-bootstrapped/scala/internal/StringContext.scala
+++ b/library/src-bootstrapped/scala/internal/StringContext.scala
@@ -7,9 +7,15 @@ object StringContext {
   inline def f(sc: => scala.StringContext)(args: Any*): String = ${ fImpl('sc, 'args) }
 
   private def fImpl(sc: Expr[StringContext], args: Expr[Seq[Any]]): Expr[String] = {
-    // TODO implement f interpolation checks and addapt sc.parts
+    // TODO implement f interpolation checks and generate optimal code
     //   See https://github.com/alemannosara/f-interpolators-in-Dotty-macros
-    '{ $sc.parts.mkString.format($args: _*) }
+    '{
+      // Purely runtime implementation of the f interpolation without any checks
+      val parts = $sc.parts.toList
+      assert(parts.nonEmpty, "StringContext should have non empty parts")
+      val parts2 = parts.head :: parts.tail.map(x => if (x.startsWith("%s")) x else "%s" + x)
+      parts2.mkString.format($args: _*)
+    }
   }
 
 }
diff --git a/tests/run-with-compiler/f-interpolator.check b/tests/run-with-compiler/f-interpolator.check
index 6a350be32166..a937551a56a4 100644
--- a/tests/run-with-compiler/f-interpolator.check
+++ b/tests/run-with-compiler/f-interpolator.check
@@ -1,2 +1,3 @@
 abc
-Hello world
+Hello world!
+Hello world!
diff --git a/tests/run-with-compiler/f-interpolator.scala b/tests/run-with-compiler/f-interpolator.scala
index 385a31d72004..32a1a4d1d981 100644
--- a/tests/run-with-compiler/f-interpolator.scala
+++ b/tests/run-with-compiler/f-interpolator.scala
@@ -2,6 +2,7 @@
 object Test {
   def main(args: Array[String]): Unit = {
     println(f"abc")
-    println(f"Hello ${"world"}%s")
+    println(f"Hello ${"world"}%s!")
+    println(f"Hello ${"world"}!")
   }
-}
\ No newline at end of file
+}

From c9c53b8f734d93af3db78a05a04dc4ed254bfda2 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Thu, 28 Mar 2019 09:37:04 +0100
Subject: [PATCH 5/8] Fix #5971: Update Scala 2 macros doc

---
 docs/docs/reference/dropped-features/macros.md | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/docs/docs/reference/dropped-features/macros.md b/docs/docs/reference/dropped-features/macros.md
index 8a3fa7cd807b..439db916ad25 100644
--- a/docs/docs/reference/dropped-features/macros.md
+++ b/docs/docs/reference/dropped-features/macros.md
@@ -1,13 +1,12 @@
 ---
 layout: doc-page
-title: Dropped: Macros
+title: Dropped: Scala 2 Macros
 ---
 
 The previous, experimental macro system has been dropped. Instead,
 there is a cleaner, more restricted system based on two complementary
-concepts: `inline` and `meta`.
-
-`inline` has been [implemented](../other-new-features/inline.md) in Dotty.
-
-`meta` is worked on in the separate [Scalameta](http://scalameta.org) project
+concepts: `inline` and `'{ ... }`/`${ ... }` code generation.
 
+* `inline` has been [implemented](../other-new-features/inline.md) in Dotty.
+* Quotes `'{ ... }` and splices `${ ... }` has been [implemented](../other-new-features/principled-meta-programming.md) in Dotty.
+  * [TASTy reflect](../other-new-features/tasty-reflect.md) provides more complex tree based APIs to inspect or create quoted code.

From c5c5f69739fe83fc0f6d7fd33d9d9ed19fa518af Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Thu, 28 Mar 2019 10:01:07 +0100
Subject: [PATCH 6/8] Fix Scala 2 Macro check

Previously we checked for `Macro | Scala2x` but the `Scala2x` was on its owner
---
 compiler/src/dotty/tools/dotc/core/Flags.scala          | 3 ---
 compiler/src/dotty/tools/dotc/core/SymDenotations.scala | 3 +++
 compiler/src/dotty/tools/dotc/typer/RefChecks.scala     | 4 ++--
 compiler/src/dotty/tools/dotc/typer/Typer.scala         | 2 +-
 tests/neg/override-scala2-macro.check                   | 3 +++
 tests/neg/override-scala2-macro.scala                   | 3 +++
 6 files changed, 12 insertions(+), 6 deletions(-)
 create mode 100644 tests/neg/override-scala2-macro.check
 create mode 100644 tests/neg/override-scala2-macro.scala

diff --git a/compiler/src/dotty/tools/dotc/core/Flags.scala b/compiler/src/dotty/tools/dotc/core/Flags.scala
index 67dc4e6fe687..4aafd2e74fb7 100644
--- a/compiler/src/dotty/tools/dotc/core/Flags.scala
+++ b/compiler/src/dotty/tools/dotc/core/Flags.scala
@@ -661,9 +661,6 @@ object Flags {
   /** Is a default parameter in Scala 2*/
   final val DefaultParameter: FlagConjunction = allOf(Param, DefaultParameterized)
 
-  /** A Scala 2 Macro */
-  final val Scala2Macro: FlagConjunction = allOf(Macro, Scala2x)
-
   /** A trait that does not need to be initialized */
   final val NoInitsTrait: FlagConjunction = allOf(Trait, NoInits)
 
diff --git a/compiler/src/dotty/tools/dotc/core/SymDenotations.scala b/compiler/src/dotty/tools/dotc/core/SymDenotations.scala
index e270cd66fdd1..dae8aa99e997 100644
--- a/compiler/src/dotty/tools/dotc/core/SymDenotations.scala
+++ b/compiler/src/dotty/tools/dotc/core/SymDenotations.scala
@@ -807,6 +807,9 @@ object SymDenotations {
                            // we need an inline flag on them only do that
                            // reduceProjection gets access to their rhs
 
+    /** Is this a Scala 2 macro */
+    final def isScala2Macro(implicit ctx: Context): Boolean = is(Macro) && symbol.owner.is(Scala2x)
+
     /** An erased value or an inline method, excluding @forceInline annotated methods.
      *  The latter have to be kept around to get to parity with Scala.
      *  This is necessary at least until we have full bootstrap. Right now
diff --git a/compiler/src/dotty/tools/dotc/typer/RefChecks.scala b/compiler/src/dotty/tools/dotc/typer/RefChecks.scala
index 1f04a4c03b6f..da7211a6294c 100644
--- a/compiler/src/dotty/tools/dotc/typer/RefChecks.scala
+++ b/compiler/src/dotty/tools/dotc/typer/RefChecks.scala
@@ -400,10 +400,10 @@ object RefChecks {
         overrideError("is an extension method, cannot override a normal method")
       } else if (other.is(Extension) && !member.is(Extension)) { // (1.9.2)
         overrideError("is a normal method, cannot override an extension method")
-      } else if ((member.isInlineMethod || member.is(Scala2Macro)) && other.is(Deferred) &&
+      } else if ((member.isInlineMethod || member.isScala2Macro) && other.is(Deferred) &&
                  member.extendedOverriddenSymbols.forall(_.is(Deferred))) { // (1.10)
         overrideError("is an inline method, must override at least one concrete method")
-      } else if (other.is(Scala2Macro) && !member.is(Scala2Macro)) { // (1.11)
+      } else if (other.isScala2Macro && !member.isScala2Macro) { // (1.11)
         overrideError("cannot be used here - only Scala-2 macros can override Scala-2 macros")
       } else if (!compatibleTypes(memberTp(self), otherTp(self)) &&
                  !compatibleTypes(memberTp(upwardsSelf), otherTp(upwardsSelf))) {
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index c00f0a9c9544..2ad7c517db2e 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -2753,7 +2753,7 @@ class Typer extends Namer
         tree.tpe <:< wildApprox(pt)
         readaptSimplified(Inliner.inlineCall(tree, pt))
       }
-      else if (tree.symbol.is(Macro, butNot = Inline)) {
+      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)
           tree
diff --git a/tests/neg/override-scala2-macro.check b/tests/neg/override-scala2-macro.check
new file mode 100644
index 000000000000..ff3f0ea88768
--- /dev/null
+++ b/tests/neg/override-scala2-macro.check
@@ -0,0 +1,3 @@
+<56..56> in override-scala2-macro.scala
+error overriding method f in class StringContext of type [A >: Any](args: Seq[A]): String;
+  method f of type [A >: Any](args: Seq[A]): String cannot be used here - only Scala-2 macros can override Scala-2 macros
diff --git a/tests/neg/override-scala2-macro.scala b/tests/neg/override-scala2-macro.scala
new file mode 100644
index 000000000000..0bb048fdb0c0
--- /dev/null
+++ b/tests/neg/override-scala2-macro.scala
@@ -0,0 +1,3 @@
+class Foo extends StringContext {
+  override inline def f[A >: Any](args: A*): String = ??? // error
+}

From 4b8f227643befeb410b062404b53b10026b702e9 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Thu, 4 Apr 2019 11:00:24 +0200
Subject: [PATCH 7/8] Add a complete description of macros

---
 docs/docs/reference/dropped-features/macros.md | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/docs/docs/reference/dropped-features/macros.md b/docs/docs/reference/dropped-features/macros.md
index 439db916ad25..ac0b93e1d1c3 100644
--- a/docs/docs/reference/dropped-features/macros.md
+++ b/docs/docs/reference/dropped-features/macros.md
@@ -3,9 +3,10 @@ layout: doc-page
 title: Dropped: Scala 2 Macros
 ---
 
-The previous, experimental macro system has been dropped. Instead,
-there is a cleaner, more restricted system based on two complementary
-concepts: `inline` and `'{ ... }`/`${ ... }` code generation.
+The previous, experimental macro system has been dropped. Instead, there is a cleaner, more restricted system based on two complementary concepts: `inline` and `'{ ... }`/`${ ... }` code generation. 
+`'{ ... }` delays the compilation of the code and produces an object containing the code, dually `${ ... }` evaluates an expression which produces code and inserts it in the surrounding `${ ... }`.
+In this setting, a definition marked as inlined containing a `${ ... }` is a macro, the code inside the `${ ... }` is executed at compile-time and produces code in the form of `'{ ... }`.
+Additionally, the contents of code can be inspected and created with a more complex reflection API (TASTy Reflect) as an extension of `'{ ... }`/`${ ... }` framework.
 
 * `inline` has been [implemented](../other-new-features/inline.md) in Dotty.
 * Quotes `'{ ... }` and splices `${ ... }` has been [implemented](../other-new-features/principled-meta-programming.md) in Dotty.

From 89412a06ec6ab705fec634da927f8c4de1808d1b Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Thu, 4 Apr 2019 11:14:39 +0200
Subject: [PATCH 8/8] Mode internal StringContext.f implementation to dotty
 package

---
 compiler/src/dotty/tools/dotc/core/Definitions.scala       | 2 +-
 compiler/src/dotty/tools/dotc/typer/Typer.scala            | 7 ++++++-
 .../{scala => dotty}/internal/StringContext.scala          | 3 ++-
 .../{scala => dotty}/internal/StringContext.scala          | 2 +-
 4 files changed, 10 insertions(+), 4 deletions(-)
 rename library/src-bootstrapped/{scala => dotty}/internal/StringContext.scala (83%)
 rename library/src-non-bootstrapped/{scala => dotty}/internal/StringContext.scala (86%)

diff --git a/compiler/src/dotty/tools/dotc/core/Definitions.scala b/compiler/src/dotty/tools/dotc/core/Definitions.scala
index d423c676e4b8..0af0526cf542 100644
--- a/compiler/src/dotty/tools/dotc/core/Definitions.scala
+++ b/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
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 2ad7c517db2e..477d4d06270d 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/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)
diff --git a/library/src-bootstrapped/scala/internal/StringContext.scala b/library/src-bootstrapped/dotty/internal/StringContext.scala
similarity index 83%
rename from library/src-bootstrapped/scala/internal/StringContext.scala
rename to library/src-bootstrapped/dotty/internal/StringContext.scala
index a10ba805ea41..04279c602c4c 100644
--- a/library/src-bootstrapped/scala/internal/StringContext.scala
+++ b/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] = {
diff --git a/library/src-non-bootstrapped/scala/internal/StringContext.scala b/library/src-non-bootstrapped/dotty/internal/StringContext.scala
similarity index 86%
rename from library/src-non-bootstrapped/scala/internal/StringContext.scala
rename to library/src-non-bootstrapped/dotty/internal/StringContext.scala
index b7500e7eea1b..c09d39b67b3f 100644
--- a/library/src-non-bootstrapped/scala/internal/StringContext.scala
+++ b/library/src-non-bootstrapped/dotty/internal/StringContext.scala
@@ -1,4 +1,4 @@
-package scala.internal
+package dotty.internal
 
 object StringContext {