Merge pull request #3604 from densh/si/8366

SI-8366 make partial function and match trees disjoint

4 files changed, 29 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
index 850030e9ba..1b8b0686e8 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
@@ -199,6 +199,10 @@ trait Reifiers { self: Quasiquotes =>
         reifyBuildCall(nme.SyntacticEmptyTypeTree)
       case SyntacticImport(expr, selectors) =>
         reifyBuildCall(nme.SyntacticImport, expr, selectors)
+      case SyntacticPartialFunction(cases) =>
+        reifyBuildCall(nme.SyntacticPartialFunction, cases)
+      case SyntacticMatch(scrutinee, cases) =>
+        reifyBuildCall(nme.SyntacticMatch, scrutinee, cases)
       case Q(tree) if fillListHole.isDefinedAt(tree) =>
         mirrorBuildCall(nme.SyntacticBlock, fillListHole(tree))
       case Q(other) =>
@@ -211,8 +215,6 @@ trait Reifiers { self: Quasiquotes =>
         reifyBuildCall(nme.SyntacticBlock, Nil)
       case Try(block, catches, finalizer) =>
         reifyBuildCall(nme.SyntacticTry, block, catches, finalizer)
-      case Match(selector, cases) =>
-        reifyBuildCall(nme.SyntacticMatch, selector, cases)
       case CaseDef(pat, guard, body) if fillListHole.isDefinedAt(body) =>
         mirrorCall(nme.CaseDef, reify(pat), reify(guard), mirrorBuildCall(nme.SyntacticBlock, fillListHole(body)))
       // parser emits trees with scala package symbol to ensure
diff --git a/src/reflect/scala/reflect/api/Internals.scala b/src/reflect/scala/reflect/api/Internals.scala
index d2e742726d..9faba7efd7 100644
--- a/src/reflect/scala/reflect/api/Internals.scala
+++ b/src/reflect/scala/reflect/api/Internals.scala
@@ -762,9 +762,15 @@ trait Internals { self: Universe =>
       def unapply(lst: List[List[Tree]]): Option[List[List[T]]]
     }
 
+    val SyntacticPartialFunction: SyntacticPartialFunctionExtractor
+    trait SyntacticPartialFunctionExtractor {
+      def apply(cases: List[Tree]): Match
+      def unapply(tree: Match): Option[List[CaseDef]]
+    }
+
     val SyntacticMatch: SyntacticMatchExtractor
     trait SyntacticMatchExtractor {
-      def apply(selector: Tree, cases: List[Tree]): Match
+      def apply(scrutinee: Tree, cases: List[Tree]): Match
       def unapply(tree: Match): Option[(Tree, List[CaseDef])]
     }
 
diff --git a/src/reflect/scala/reflect/internal/ReificationSupport.scala b/src/reflect/scala/reflect/internal/ReificationSupport.scala
index dfe1811ff0..9a130337b4 100644
--- a/src/reflect/scala/reflect/internal/ReificationSupport.scala
+++ b/src/reflect/scala/reflect/internal/ReificationSupport.scala
@@ -850,9 +850,24 @@ trait ReificationSupport { self: SymbolTable =>
       case tree => throw new IllegalArgumentException("$tree is not valid representation of pattern match case")
     }
 
+    object SyntacticPartialFunction extends SyntacticPartialFunctionExtractor {
+      def apply(cases: List[Tree]): Match = Match(EmptyTree, mkCases(cases))
+      def unapply(tree: Match): Option[List[CaseDef]] = tree match {
+        case Match(EmptyTree, cases) => Some(cases)
+        case _                       => None
+      }
+    }
+
     object SyntacticMatch extends SyntacticMatchExtractor {
-      def apply(selector: Tree, cases: List[Tree]) = Match(selector, mkCases(cases))
-      def unapply(tree: Match): Option[(Tree, List[CaseDef])] = Match.unapply(tree)
+      def apply(scrutinee: Tree, cases: List[Tree]) = {
+        require(scrutinee.nonEmpty, "match's scrutinee may not be empty")
+        Match(scrutinee, mkCases(cases))
+      }
+
+      def unapply(tree: Match): Option[(Tree, List[CaseDef])] = tree match {
+        case Match(scrutinee, cases) if scrutinee.nonEmpty => Some((scrutinee, cases))
+        case _                                             => None
+      }
     }
 
     object SyntacticTry extends SyntacticTryExtractor {
diff --git a/src/reflect/scala/reflect/internal/StdNames.scala b/src/reflect/scala/reflect/internal/StdNames.scala
index 640e0606c7..10959ff41f 100644
--- a/src/reflect/scala/reflect/internal/StdNames.scala
+++ b/src/reflect/scala/reflect/internal/StdNames.scala
@@ -630,6 +630,7 @@ trait StdNames {
     val SyntacticNew: NameType         = "SyntacticNew"
     val SyntacticObjectDef: NameType   = "SyntacticObjectDef"
     val SyntacticPackageObjectDef: NameType = "SyntacticPackageObjectDef"
+    val SyntacticPartialFunction: NameType = "SyntacticPartialFunction"
     val SyntacticPatDef: NameType      = "SyntacticPatDef"
     val SyntacticSelectType: NameType  = "SyntacticSelectType"
     val SyntacticSelectTerm: NameType  = "SyntacticSelectTerm"