Merge pull request #1775 from dotty-staging/add-implicit-funtypes

Add implicit function types

1 files changed, 16 insertions, 7 deletions

diff --git a/compiler/src/dotty/tools/dotc/ast/Desugar.scala b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
index bb15edf5a..db78cfffb 100644
--- a/compiler/src/dotty/tools/dotc/ast/Desugar.scala
+++ b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
@@ -123,6 +123,13 @@ object desugar {
     else vdef
   }
 
+  def makeImplicitParameters(tpts: List[Tree], forPrimaryConstructor: Boolean)(implicit ctx: Context) =
+    for (tpt <- tpts) yield {
+       val paramFlags: FlagSet = if (forPrimaryConstructor) PrivateLocalParamAccessor else Param
+       val epname = ctx.freshName(nme.EVIDENCE_PARAM_PREFIX).toTermName
+       ValDef(epname, tpt, EmptyTree).withFlags(paramFlags | Implicit)
+    }
+
   /** Expand context bounds to evidence params. E.g.,
    *
    *      def f[T >: L <: H : B](params)
@@ -143,19 +150,16 @@ object desugar {
     val epbuf = new ListBuffer[ValDef]
     def desugarContextBounds(rhs: Tree): Tree = rhs match {
       case ContextBounds(tbounds, cxbounds) =>
-        for (cxbound <- cxbounds) {
-          val paramFlags: FlagSet = if (isPrimaryConstructor) PrivateLocalParamAccessor else Param
-          val epname = ctx.freshName(nme.EVIDENCE_PARAM_PREFIX).toTermName
-          epbuf += ValDef(epname, cxbound, EmptyTree).withFlags(paramFlags | Implicit)
-        }
+        for (cxbound <- cxbounds)
+          epbuf ++= makeImplicitParameters(cxbounds, isPrimaryConstructor)
         tbounds
       case PolyTypeTree(tparams, body) =>
         cpy.PolyTypeTree(rhs)(tparams, desugarContextBounds(body))
       case _ =>
         rhs
     }
-    val tparams1 = tparams mapConserve { tdef =>
-      cpy.TypeDef(tdef)(rhs = desugarContextBounds(tdef.rhs))
+    val tparams1 = tparams mapConserve { tparam =>
+      cpy.TypeDef(tparam)(rhs = desugarContextBounds(tparam.rhs))
     }
 
     val meth1 = addEvidenceParams(cpy.DefDef(meth)(tparams = tparams1), epbuf.toList)
@@ -680,6 +684,11 @@ object desugar {
     Function(param :: Nil, Block(vdefs, body))
   }
 
+  def makeImplicitFunction(formals: List[Type], body: Tree)(implicit ctx: Context): Tree = {
+    val params = makeImplicitParameters(formals.map(TypeTree), forPrimaryConstructor = false)
+    new ImplicitFunction(params, body)
+  }
+
   /** Add annotation with class `cls` to tree:
    *      tree @cls
    */