Merge pull request #3455 from densh/topic/patdef

Fix SI-8202 and improve support for splicing patterns into vals

5 files changed, 64 insertions, 34 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index 5dadbd0825..8271363527 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -2492,7 +2492,7 @@ self =>
       def mkDefs(p: Tree, tp: Tree, rhs: Tree): List[Tree] = {
         val trees = {
           val pat = if (tp.isEmpty) p else Typed(p, tp) setPos (p.pos union tp.pos)
-          gen.mkPatDef(newmods, pat, rhs)
+          makePatDef(newmods, pat, rhs)
         }
         if (newmods.isDeferred) {
           trees match {
diff --git a/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala b/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
index 525dcffb0c..6e5a3f6ef7 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
@@ -168,4 +168,6 @@ abstract class TreeBuilder {
         vparamss ::: List(evidenceParams)
     }
   }
+
+  def makePatDef(mods: Modifiers, pat: Tree, rhs: Tree) = gen.mkPatDef(mods, pat, rhs)
 }
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
index 9f6807fe17..301e7051df 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
@@ -14,6 +14,7 @@ import scala.util.Try
  */
 trait Parsers { self: Quasiquotes =>
   import global.{Try => _, _}
+  import build.implodePatDefs
 
   abstract class Parser extends {
     val global: self.global.type = self.global
@@ -61,12 +62,10 @@ trait Parsers { self: Quasiquotes =>
         override implicit def fresh: FreshNameCreator = parser.fresh
 
         // q"(..$xs)"
-        override def makeTupleTerm(trees: List[Tree]): Tree =
-          Apply(Ident(nme.QUASIQUOTE_TUPLE), trees)
+        override def makeTupleTerm(trees: List[Tree]): Tree = TuplePlaceholder(trees)
 
         // tq"(..$xs)"
-        override def makeTupleType(trees: List[Tree]): Tree =
-          AppliedTypeTree(Ident(tpnme.QUASIQUOTE_TUPLE), trees)
+        override def makeTupleType(trees: List[Tree]): Tree = TupleTypePlaceholder(trees)
 
         // q"{ $x }"
         override def makeBlock(stats: List[Tree]): Tree = stats match {
@@ -75,30 +74,32 @@ trait Parsers { self: Quasiquotes =>
         }
 
         // tq"$a => $b"
-        override def makeFunctionTypeTree(argtpes: List[Tree], restpe: Tree): Tree =
-          AppliedTypeTree(Ident(tpnme.QUASIQUOTE_FUNCTION), argtpes :+ restpe)
+        override def makeFunctionTypeTree(argtpes: List[Tree], restpe: Tree): Tree = FunctionTypePlaceholder(argtpes, restpe)
+
+        // make q"val (x: T) = rhs" be equivalent to q"val x: T = rhs" for sake of bug compatibility (SI-8211)
+        override def makePatDef(mods: Modifiers, pat: Tree, rhs: Tree) = pat match {
+          case TuplePlaceholder(inParensPat :: Nil) => super.makePatDef(mods, inParensPat, rhs)
+          case _ => super.makePatDef(mods, pat, rhs)
+        }
       }
       import treeBuilder.{global => _, unit => _, _}
 
-      def quasiquoteParam(name: Name, flags: FlagSet = NoFlags) =
-        ValDef(Modifiers(flags), name.toTermName, Ident(tpnme.QUASIQUOTE_PARAM), EmptyTree)
-
       // q"def foo($x)"
       override def param(owner: Name, implicitmod: Int, caseParam: Boolean): ValDef =
         if (isHole && lookingAhead { in.token == COMMA || in.token == RPAREN }) {
-          quasiquoteParam(ident(), implicitmod)
+          ParamPlaceholder(implicitmod, ident())
         } else super.param(owner, implicitmod, caseParam)
 
       // q"($x) => ..." && q"class X { selfie => }
       override def convertToParam(tree: Tree): ValDef = tree match {
-        case Ident(name) if isHole(name) => quasiquoteParam(name)
+        case Ident(name) if isHole(name) => ParamPlaceholder(NoFlags, name)
         case _ => super.convertToParam(tree)
       }
 
       // q"foo match { case $x }"
       override def caseClause(): CaseDef =
         if (isHole && lookingAhead { in.token == CASE || in.token == RBRACE || in.token == SEMI }) {
-          val c = makeCaseDef(Apply(Ident(nme.QUASIQUOTE_CASE), List(Ident(ident()))), EmptyTree, EmptyTree)
+          val c = CasePlaceholder(ident())
           while (in.token == SEMI) in.nextToken()
           c
         } else
@@ -132,7 +133,7 @@ trait Parsers { self: Quasiquotes =>
           in.nextToken()
           annot :: readAnnots(annot)
         case _ if isHole && lookingAhead { isAnnotation || isModifier || isDefIntro || isIdent || isStatSep || in.token == LPAREN } =>
-          val ann = Apply(Select(New(Ident(tpnme.QUASIQUOTE_MODS)), nme.CONSTRUCTOR), List(Literal(Constant(in.name.toString))))
+          val ann = ModsPlaceholder(in.name)
           in.nextToken()
           ann :: readAnnots(annot)
         case _ =>
@@ -141,13 +142,13 @@ trait Parsers { self: Quasiquotes =>
 
       override def refineStat(): List[Tree] =
         if (isHole && !isDclIntro) {
-          val result = ValDef(NoMods, in.name, Ident(tpnme.QUASIQUOTE_REFINE_STAT), EmptyTree) :: Nil
+          val result = RefineStatPlaceholder(in.name) :: Nil
           in.nextToken()
           result
         } else super.refineStat()
 
       override def ensureEarlyDef(tree: Tree) = tree match {
-        case Ident(name: TermName) if isHole(name) => ValDef(NoMods | Flag.PRESUPER, name, Ident(tpnme.QUASIQUOTE_EARLY_DEF), EmptyTree)
+        case Ident(name: TermName) if isHole(name) => EarlyDefPlaceholder(name)
         case _ => super.ensureEarlyDef(tree)
       }
 
@@ -158,14 +159,14 @@ trait Parsers { self: Quasiquotes =>
 
       override def topStat = super.topStat.orElse {
         case _ if isHole =>
-          val stats = ValDef(NoMods, in.name, Ident(tpnme.QUASIQUOTE_PACKAGE_STAT), EmptyTree) :: Nil
+          val stats = PackageStatPlaceholder(in.name) :: Nil
           in.nextToken()
           stats
       }
 
       override def enumerator(isFirst: Boolean, allowNestedIf: Boolean = true) =
         if (isHole && lookingAhead { in.token == EOF || in.token == RPAREN || isStatSep }) {
-          val res = build.SyntacticValFrom(Bind(in.name, Ident(nme.WILDCARD)), Ident(nme.QUASIQUOTE_FOR_ENUM)) :: Nil
+          val res = ForEnumPlaceholder(in.name) :: Nil
           in.nextToken()
           res
         } else super.enumerator(isFirst, allowNestedIf)
@@ -182,7 +183,7 @@ trait Parsers { self: Quasiquotes =>
   }
 
   object TermParser extends Parser {
-    def entryPoint = parser => Q(gen.mkTreeOrBlock(parser.templateOrTopStatSeq()))
+    def entryPoint = parser => Q(implodePatDefs(gen.mkTreeOrBlock(parser.templateOrTopStatSeq())))
   }
 
   object TypeParser extends Parser {
@@ -195,7 +196,7 @@ trait Parsers { self: Quasiquotes =>
   }
 
   object CaseParser extends Parser {
-    def entryPoint = _.caseClause()
+    def entryPoint = parser => implodePatDefs(parser.caseClause())
   }
 
   object PatternParser extends Parser {
@@ -209,7 +210,7 @@ trait Parsers { self: Quasiquotes =>
     def entryPoint = { parser =>
       val enums = parser.enumerator(isFirst = false, allowNestedIf = false)
       assert(enums.length == 1)
-      enums.head
+      implodePatDefs(enums.head)
     }
   }
 
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala b/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
index 825d0c04f3..130a01332b 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
@@ -100,6 +100,8 @@ trait Placeholders { self: Quasiquotes =>
   }
 
   object ModsPlaceholder extends HolePlaceholder {
+    def apply(name: Name) =
+      Apply(Select(New(Ident(tpnme.QUASIQUOTE_MODS)), nme.CONSTRUCTOR), List(Literal(Constant(name.toString))))
     def matching = {
       case Apply(Select(New(Ident(tpnme.QUASIQUOTE_MODS)), nme.CONSTRUCTOR), List(Literal(Constant(s: String)))) => TermName(s)
     }
@@ -112,12 +114,16 @@ trait Placeholders { self: Quasiquotes =>
   }
 
   object ParamPlaceholder extends HolePlaceholder {
+    def apply(flags: FlagSet, name: Name) =
+      ValDef(Modifiers(flags), nme.QUASIQUOTE_PARAM, Ident(name), EmptyTree)
     def matching = {
-      case ValDef(_, name, Ident(tpnme.QUASIQUOTE_PARAM), EmptyTree) => name
+      case ValDef(_, nme.QUASIQUOTE_PARAM, Ident(name), EmptyTree) => name
     }
   }
 
   object TuplePlaceholder {
+    def apply(args: List[Tree]) =
+      Apply(Ident(nme.QUASIQUOTE_TUPLE), args)
     def unapply(tree: Tree): Option[List[Tree]] = tree match {
       case Apply(Ident(nme.QUASIQUOTE_TUPLE), args) => Some(args)
       case _ => None
@@ -125,6 +131,8 @@ trait Placeholders { self: Quasiquotes =>
   }
 
   object TupleTypePlaceholder {
+    def apply(args: List[Tree]) =
+      AppliedTypeTree(Ident(tpnme.QUASIQUOTE_TUPLE), args)
     def unapply(tree: Tree): Option[List[Tree]] = tree match {
       case AppliedTypeTree(Ident(tpnme.QUASIQUOTE_TUPLE), args) => Some(args)
       case _ => None
@@ -132,6 +140,8 @@ trait Placeholders { self: Quasiquotes =>
   }
 
   object FunctionTypePlaceholder {
+    def apply(args: List[Tree], res: Tree) =
+      AppliedTypeTree(Ident(tpnme.QUASIQUOTE_FUNCTION), args :+ res)
     def unapply(tree: Tree): Option[(List[Tree], Tree)] = tree match {
       case AppliedTypeTree(Ident(tpnme.QUASIQUOTE_FUNCTION), args :+ res) => Some((args, res))
       case _ => None
@@ -146,6 +156,8 @@ trait Placeholders { self: Quasiquotes =>
   }
 
   object CasePlaceholder {
+    def apply(name: Name) =
+      CaseDef(Apply(Ident(nme.QUASIQUOTE_CASE), Ident(name) :: Nil), EmptyTree, EmptyTree)
     def unapply(tree: Tree): Option[Hole] = tree match {
       case CaseDef(Apply(Ident(nme.QUASIQUOTE_CASE), List(Placeholder(hole))), EmptyTree, EmptyTree) => Some(hole)
       case _ => None
@@ -153,27 +165,35 @@ trait Placeholders { self: Quasiquotes =>
   }
 
   object RefineStatPlaceholder {
+    def apply(name: Name) =
+      ValDef(NoMods, nme.QUASIQUOTE_REFINE_STAT, Ident(name), EmptyTree)
     def unapply(tree: Tree): Option[Hole] = tree match {
-      case ValDef(_, Placeholder(hole), Ident(tpnme.QUASIQUOTE_REFINE_STAT), _) => Some(hole)
+      case ValDef(_, nme.QUASIQUOTE_REFINE_STAT, Ident(Placeholder(hole)), _) => Some(hole)
       case _ => None
     }
   }
 
   object EarlyDefPlaceholder {
+    def apply(name: Name) =
+      ValDef(Modifiers(Flag.PRESUPER), nme.QUASIQUOTE_EARLY_DEF, Ident(name), EmptyTree)
     def unapply(tree: Tree): Option[Hole] = tree match {
-      case ValDef(_, Placeholder(hole), Ident(tpnme.QUASIQUOTE_EARLY_DEF), _) => Some(hole)
+      case ValDef(_, nme.QUASIQUOTE_EARLY_DEF, Ident(Placeholder(hole)), _) => Some(hole)
       case _ => None
     }
   }
 
   object PackageStatPlaceholder {
+    def apply(name: Name) =
+      ValDef(NoMods, nme.QUASIQUOTE_PACKAGE_STAT, Ident(name), EmptyTree)
     def unapply(tree: Tree): Option[Hole] = tree match {
-      case ValDef(NoMods, Placeholder(hole), Ident(tpnme.QUASIQUOTE_PACKAGE_STAT), EmptyTree) => Some(hole)
+      case ValDef(NoMods, nme.QUASIQUOTE_PACKAGE_STAT, Ident(Placeholder(hole)), EmptyTree) => Some(hole)
       case _ => None
     }
   }
 
   object ForEnumPlaceholder {
+    def apply(name: Name) =
+      build.SyntacticValFrom(Bind(name, Ident(nme.WILDCARD)), Ident(nme.QUASIQUOTE_FOR_ENUM))
     def unapply(tree: Tree): Option[Hole] = tree match {
       case build.SyntacticValFrom(Bind(Placeholder(hole), Ident(nme.WILDCARD)), Ident(nme.QUASIQUOTE_FOR_ENUM)) =>
         Some(hole)
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
index 017e966f63..70580adbce 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
@@ -194,8 +194,8 @@ trait Reifiers { self: Quasiquotes =>
         reifyBuildCall(nme.SyntacticEmptyTypeTree)
       case SyntacticImport(expr, selectors) =>
         reifyBuildCall(nme.SyntacticImport, expr, selectors)
-      case Q(Placeholder(Hole(tree, DotDot))) =>
-        mirrorBuildCall(nme.SyntacticBlock, tree)
+      case Q(tree) if fillListHole.isDefinedAt(tree) =>
+        mirrorBuildCall(nme.SyntacticBlock, fillListHole(tree))
       case Q(other) =>
         reifyTree(other)
       // Syntactic block always matches so we have to be careful
@@ -311,11 +311,7 @@ trait Reifiers { self: Quasiquotes =>
      */
     def reifyMultiCardinalityList(xs: List[Any])(fill: PartialFunction[Any, Tree])(fallback: Any => Tree): Tree
 
-    /** Reifies arbitrary list filling ..$x and ...$y holeMap when they are put
-     *  in the correct position. Fallbacks to regular reification for non-high cardinality
-     *  elements.
-     */
-    override def reifyList(xs: List[Any]): Tree = reifyMultiCardinalityList(xs) {
+    val fillListHole: PartialFunction[Any, Tree] = {
       case Placeholder(Hole(tree, DotDot)) => tree
       case CasePlaceholder(Hole(tree, DotDot)) => tree
       case RefineStatPlaceholder(h @ Hole(_, DotDot)) => reifyRefineStat(h)
@@ -323,12 +319,23 @@ trait Reifiers { self: Quasiquotes =>
       case PackageStatPlaceholder(h @ Hole(_, DotDot)) => reifyPackageStat(h)
       case ForEnumPlaceholder(Hole(tree, DotDot)) => tree
       case ParamPlaceholder(Hole(tree, DotDot)) => tree
+      case SyntacticPatDef(mods, pat, tpt, rhs) =>
+        reifyBuildCall(nme.SyntacticPatDef, mods, pat, tpt, rhs)
+      case SyntacticValDef(mods, p @ Placeholder(h: ApplyHole), tpt, rhs) if h.tpe <:< treeType =>
+        mirrorBuildCall(nme.SyntacticPatDef, reify(mods), h.tree, reify(tpt), reify(rhs))
+    }
+
+    val fillListOfListsHole: PartialFunction[Any, Tree] = {
       case List(ParamPlaceholder(Hole(tree, DotDotDot))) => tree
       case List(Placeholder(Hole(tree, DotDotDot))) => tree
-    } {
-      reify(_)
     }
 
+    /** Reifies arbitrary list filling ..$x and ...$y holeMap when they are put
+     *  in the correct position. Fallbacks to regular reification for non-high cardinality
+     *  elements.
+     */
+    override def reifyList(xs: List[Any]): Tree = reifyMultiCardinalityList(xs)(fillListHole.orElse(fillListOfListsHole))(reify)
+
     def reifyAnnotList(annots: List[Tree]): Tree = reifyMultiCardinalityList(annots) {
       case AnnotPlaceholder(h @ Hole(_, DotDot)) => reifyAnnotation(h)
     } {