SI-7803 support for matching of anonymous function literals

8 files changed, 60 insertions, 8 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index f52ed60480..70b32f08ae 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -1445,7 +1445,7 @@ self =>
           // The case still missed is unparenthesized single argument, like "x: Int => x + 1", which
           // may be impossible to distinguish from a self-type and so remains an error.  (See #1564)
           def lhsIsTypedParamList() = t match {
-            case Parens(xs) if xs forall (_.isInstanceOf[Typed]) => true
+            case Parens(xs) if xs.forall(isTypedParam) => true
             case _ => false
           }
           if (in.token == ARROW && (location != InTemplate || lhsIsTypedParamList)) {
@@ -1458,6 +1458,8 @@ self =>
         parseOther
     }
 
+    def isTypedParam(t: Tree) = t.isInstanceOf[Typed]
+
     /** {{{
      *  Expr ::= implicit Id => Expr
      *  }}}
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
index 868c74ebcd..19888fa8d2 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
@@ -135,6 +135,11 @@ trait Parsers { self: Quasiquotes =>
         case Ident(name: TermName) if isHole(name) => ValDef(NoMods | Flag.PRESUPER, name, Ident(tpnme.QUASIQUOTE_EARLY_DEF), EmptyTree)
         case _ => super.ensureEarlyDef(tree)
       }
+
+      override def isTypedParam(tree: Tree) = super.isTypedParam(tree) || (tree match {
+        case Ident(name) if isHole(name) => true
+        case _ => false
+      })
     }
   }
 
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
index 53b2e4cc96..fa305f3d07 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
@@ -8,7 +8,8 @@ import scala.reflect.internal.Flags._
 trait Reifiers { self: Quasiquotes =>
   import global._
   import global.build.{SyntacticClassDef, SyntacticTraitDef, SyntacticModuleDef,
-                       SyntacticBlock, SyntacticApplied, SyntacticTypeApplied}
+                       SyntacticBlock, SyntacticApplied, SyntacticTypeApplied,
+                       SyntacticFunction}
   import global.treeInfo._
   import global.definitions._
   import Cardinality._
@@ -67,6 +68,8 @@ trait Reifiers { self: Quasiquotes =>
         reifyBuildCall(nme.SyntacticApplied, fun, argss)
       case SyntacticTypeApplied(fun, targs) if targs.nonEmpty =>
         reifyBuildCall(nme.SyntacticTypeApplied, fun, targs)
+      case SyntacticFunction(args, body) =>
+        reifyBuildCall(nme.SyntacticFunction, args, body)
       case Block(stats, last) =>
         reifyBuildCall(nme.SyntacticBlock, stats :+ last)
       // parser emits trees with scala package symbol to ensure
diff --git a/src/reflect/scala/reflect/api/BuildUtils.scala b/src/reflect/scala/reflect/api/BuildUtils.scala
index 108efee37c..8b2e02c639 100644
--- a/src/reflect/scala/reflect/api/BuildUtils.scala
+++ b/src/reflect/scala/reflect/api/BuildUtils.scala
@@ -160,5 +160,13 @@ private[reflect] trait BuildUtils { self: Universe =>
       def apply(argtpes: List[Tree], restpe: Tree): Tree
       def unapply(tree: Tree): Option[(List[Tree], Tree)]
     }
+
+    val SyntacticFunction: SyntacticFunctionExtractor
+
+    trait SyntacticFunctionExtractor {
+      def apply(params: List[ValDef], body: Tree): Tree
+
+      def unapply(tree: Tree): Option[(List[ValDef], Tree)]
+    }
   }
 }
diff --git a/src/reflect/scala/reflect/internal/BuildUtils.scala b/src/reflect/scala/reflect/internal/BuildUtils.scala
index 528b542361..936ca91c68 100644
--- a/src/reflect/scala/reflect/internal/BuildUtils.scala
+++ b/src/reflect/scala/reflect/internal/BuildUtils.scala
@@ -70,11 +70,12 @@ trait BuildUtils { self: SymbolTable =>
       case _ => throw new IllegalArgumentException(s"Tree ${showRaw(tree)} isn't a correct representation of annotation, consider passing Ident as a first argument")
     }
 
-    def mkVparamss(argss: List[List[ValDef]]): List[List[ValDef]] = {
-      argss.map { _.map {
-        case vd @ ValDef(mods, _, _, EmptyTree) => copyValDef(vd)(mods = mods | PARAM)
-        case vd @ ValDef(mods, _, _, _) => copyValDef(vd)(mods = mods | PARAM | DEFAULTPARAM)
-      } }
+    def mkVparamss(argss: List[List[ValDef]]): List[List[ValDef]] = argss.map(_.map(mkParam))
+
+    def mkParam(vd: ValDef): ValDef = {
+      var newmods = (vd.mods | PARAM) & (~DEFERRED)
+      if (vd.rhs.nonEmpty) newmods |= DEFAULTPARAM
+      copyValDef(vd)(mods = newmods)
     }
 
     def mkTparams(tparams: List[Tree]): List[TypeDef] =
@@ -327,6 +328,21 @@ trait BuildUtils { self: SymbolTable =>
         case _ => None
       }
     }
+
+    object SyntacticFunction extends SyntacticFunctionExtractor {
+      def apply(params: List[ValDef], body: Tree): Tree = {
+        val params0 = params.map { arg =>
+          require(arg.rhs.isEmpty, "anonymous functions don't support default values")
+          mkParam(arg)
+        }
+        Function(params0, body)
+      }
+
+      def unapply(tree: Tree): Option[(List[ValDef], Tree)] = tree match {
+        case Function(params, body) => Some((params, body))
+        case _ => None
+      }
+    }
   }
 
   val build: BuildApi = new BuildImpl
diff --git a/src/reflect/scala/reflect/internal/StdNames.scala b/src/reflect/scala/reflect/internal/StdNames.scala
index 936445f011..b9a32c481f 100644
--- a/src/reflect/scala/reflect/internal/StdNames.scala
+++ b/src/reflect/scala/reflect/internal/StdNames.scala
@@ -592,6 +592,7 @@ trait StdNames {
     val SyntacticApplied: NameType     = "SyntacticApplied"
     val SyntacticBlock: NameType       = "SyntacticBlock"
     val SyntacticClassDef: NameType    = "SyntacticClassDef"
+    val SyntacticFunction: NameType    = "SyntacticFunction"
     val SyntacticFunctionType: NameType= "SyntacticFunctionType"
     val SyntacticModuleDef: NameType   = "SyntacticModuleDef"
     val SyntacticTraitDef: NameType    = "SyntacticTraitDef"
diff --git a/test/files/scalacheck/quasiquotes/TermConstructionProps.scala b/test/files/scalacheck/quasiquotes/TermConstructionProps.scala
index 599dfd442a..c6cca85c81 100644
--- a/test/files/scalacheck/quasiquotes/TermConstructionProps.scala
+++ b/test/files/scalacheck/quasiquotes/TermConstructionProps.scala
@@ -157,4 +157,14 @@ object TermConstructionProps extends QuasiquoteProperties("term construction") {
     val empty = List[Tree]()
     assert(q"(..$empty)" ≈ q"()")
   }
+
+  property("function param flags are the same") = test {
+    val xy = q"val x: A" :: q"val y: B" :: Nil
+    assertEqAst(q"(..$xy) => x + y", "(x: A, y: B) => x + y")
+  }
+
+  property("anonymous functions don't support default values") = test {
+    val x = q"val x: Int = 1"
+    assertThrows[IllegalArgumentException] { q"($x) => x" }
+  }
 }
diff --git a/test/files/scalacheck/quasiquotes/TermDeconstructionProps.scala b/test/files/scalacheck/quasiquotes/TermDeconstructionProps.scala
index 6087bbdb74..762625a46a 100644
--- a/test/files/scalacheck/quasiquotes/TermDeconstructionProps.scala
+++ b/test/files/scalacheck/quasiquotes/TermDeconstructionProps.scala
@@ -67,4 +67,11 @@ object TermDeconstructionProps extends QuasiquoteProperties("term deconstruction
     val q"{ ..$xs }" = q"{ x1; x2; x3 }"
     assert(xs ≈ List(q"x1", q"x2", q"x3"))
   }
-}
\ No newline at end of file
+
+  property("exhaustive function matcher") = test {
+    def matches(line: String) { val q"(..$args) => $body" = parse(line) }
+    matches("() => bippy")
+    matches("(y: Y) => y oh y")
+    matches("(x: X, y: Y) => x and y")
+  }
+}