From a907887158a469b6a21d027fd37bc360e9009b2f Mon Sep 17 00:00:00 2001
From: Eugene Burmako <xeno.by@gmail.com>
Date: Thu, 22 May 2014 22:21:10 +0200
Subject: adds MacroPlugin.pluginsIsBlackbox

This is an important omission in the current macro plugin API, which was
designed before the blackbox vs whitebox separation was implemented.

Even if one overrides pluginsTypedMacroBody and pluginsMacroExpand,
that would still be not enough to write a custom macro expander, because
typedImplicit1 uses isBlackbox, which is tightly coupled with the standard
way of reading/writing macro signatures.
---
 .../scala/tools/nsc/typechecker/AnalyzerPlugins.scala  | 18 ++++++++++++++++++
 src/compiler/scala/tools/nsc/typechecker/Macros.scala  |  7 ++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

(limited to 'src/compiler/scala/tools')

diff --git a/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala b/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala
index fa6e5399eb..5a70d4c524 100644
--- a/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala
@@ -189,6 +189,16 @@ trait AnalyzerPlugins { self: Analyzer =>
      */
     def pluginsTypedMacroBody(typer: Typer, ddef: DefDef): Option[Tree] = None
 
+    /**
+     * Figures out whether the given macro definition is blackbox or whitebox.
+     *
+     * Default implementation provided in `self.standardIsBlackbox` loads the macro impl binding
+     * and fetches boxity from the "isBlackbox" field of the macro signature.
+     *
+     * $nonCumulativeReturnValueDoc.
+     */
+    def pluginsIsBlackbox(macroDef: Symbol): Option[Boolean] = None
+
     /**
      * Expands an application of a def macro (i.e. of a symbol that has the MACRO flag set),
      * possibly using the current typer mode and the provided prototype.
@@ -375,6 +385,14 @@ trait AnalyzerPlugins { self: Analyzer =>
     def custom(plugin: MacroPlugin) = plugin.pluginsTypedMacroBody(typer, ddef)
   })
 
+  /** @see MacroPlugin.pluginsIsBlackbox */
+  def pluginsIsBlackbox(macroDef: Symbol): Boolean = invoke(new NonCumulativeOp[Boolean] {
+    def position = macroDef.pos
+    def description = "compute boxity for this macro definition"
+    def default = standardIsBlackbox(macroDef)
+    def custom(plugin: MacroPlugin) = plugin.pluginsIsBlackbox(macroDef)
+  })
+
   /** @see MacroPlugin.pluginsMacroExpand */
   def pluginsMacroExpand(typer: Typer, expandee: Tree, mode: Mode, pt: Type): Tree = invoke(new NonCumulativeOp[Tree] {
     def position = expandee.pos
diff --git a/src/compiler/scala/tools/nsc/typechecker/Macros.scala b/src/compiler/scala/tools/nsc/typechecker/Macros.scala
index f4456998c0..aa7a570937 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Macros.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Macros.scala
@@ -263,7 +263,12 @@ trait Macros extends MacroRuntimes with Traces with Helpers {
     }
 
   def isBlackbox(expandee: Tree): Boolean = isBlackbox(dissectApplied(expandee).core.symbol)
-  def isBlackbox(macroDef: Symbol): Boolean = {
+  def isBlackbox(macroDef: Symbol): Boolean = pluginsIsBlackbox(macroDef)
+
+  /** Default implementation of `isBlackbox`.
+   *  Can be overridden by analyzer plugins (see AnalyzerPlugins.pluginsIsBlackbox for more details)
+   */
+  def standardIsBlackbox(macroDef: Symbol): Boolean = {
     val fastTrackBoxity = fastTrack.get(macroDef).map(_.isBlackbox)
     val bindingBoxity = loadMacroImplBinding(macroDef).map(_.isBlackbox)
     fastTrackBoxity orElse bindingBoxity getOrElse false
-- 
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