5 files changed, 34 insertions, 3 deletions
diff --git a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
index ee8db61020..0a98d45cac 100644
--- a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
@@ -168,6 +168,7 @@ trait ScalaSettings extends AbsScalaSettings
   val Yrangepos       = BooleanSetting    ("-Yrangepos", "Use range positions for syntax trees.")
   val Ybuilderdebug   = ChoiceSetting     ("-Ybuilder-debug", "manager", "Compile using the specified build manager.", List("none", "refined", "simple"), "none")
   val Yreifycopypaste = BooleanSetting    ("-Yreify-copypaste", "Dump the reified trees in copypasteable representation.")
+  val Ymacronoexpand  = BooleanSetting    ("-Ymacro-no-expand", "Don't expand macros. Might be useful for scaladoc and presentation compiler, but will crash anything which uses macros and gets past typer.")
   val Yreplsync       = BooleanSetting    ("-Yrepl-sync", "Do not use asynchronous code for repl startup")
   val Ynotnull        = BooleanSetting    ("-Ynotnull", "Enable (experimental and incomplete) scala.NotNull.")
   val YmethodInfer    = BooleanSetting    ("-Yinfer-argument-types", "Infer types for arguments of overriden methods.")
diff --git a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
index 2e5d61cc6b..fbf23968f0 100644
--- a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
@@ -760,10 +760,14 @@ trait ContextErrors {
             else " of " + expanded.getClass
         ))
 
-      def MacroImplementationNotFoundError(expandee: Tree) =
-        macroExpansionError(expandee,
+      def MacroImplementationNotFoundError(expandee: Tree) = {
+        val message =
           "macro implementation not found: " + expandee.symbol.name + " " +
-          "(the most common reason for that is that you cannot use macro implementations in the same compilation run that defines them)")
+          "(the most common reason for that is that you cannot use macro implementations in the same compilation run that defines them)" +
+          (if (forScaladoc) ". When generating scaladocs for multiple projects at once, consider using -Ymacro-no-expand to disable macro expansions altogether."
+           else "")
+        macroExpansionError(expandee, message)
+      }
     }
   }
 
diff --git a/src/compiler/scala/tools/nsc/typechecker/Macros.scala b/src/compiler/scala/tools/nsc/typechecker/Macros.scala
index 0ba76643ca..245656e2d7 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Macros.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Macros.scala
@@ -684,6 +684,7 @@ trait Macros extends scala.tools.reflect.FastTrack with Traces {
    *    the expandee with an error marker set   if there has been an error
    */
   def macroExpand(typer: Typer, expandee: Tree, mode: Int = EXPRmode, pt: Type = WildcardType): Tree = {
+    if (settings.Ymacronoexpand.value) return expandee // SI-6812
     val start = if (Statistics.canEnable) Statistics.startTimer(macroExpandNanos) else null
     if (Statistics.canEnable) Statistics.incCounter(macroExpandCount)
     try {
diff --git a/test/scaladoc/run/SI-6812.check b/test/scaladoc/run/SI-6812.check
new file mode 100644
index 0000000000..619c56180b
--- /dev/null
+++ b/test/scaladoc/run/SI-6812.check
@@ -0,0 +1 @@
+Done.
diff --git a/test/scaladoc/run/SI-6812.scala b/test/scaladoc/run/SI-6812.scala
new file mode 100644
index 0000000000..fbd9588ede
--- /dev/null
+++ b/test/scaladoc/run/SI-6812.scala
@@ -0,0 +1,24 @@
+import scala.tools.nsc.doc.model._
+import scala.tools.partest.ScaladocModelTest
+import language._
+
+object Test extends ScaladocModelTest {
+
+  override def code = """
+    import scala.reflect.macros.Context
+    import language.experimental.macros
+
+    object Macros {
+      def impl(c: Context) = c.literalUnit
+      def foo = macro impl
+    }
+
+    class C {
+      def bar = Macros.foo
+    }
+  """
+
+  def scaladocSettings = ""
+  override def extraSettings = super.extraSettings + " -Ymacro-no-expand"
+  def testModel(root: Package) = ()
+}