Taking a fully-defined result type into account when forming a closure.

Given

     (params) => body

and an expected type

     Ts => R

with R fully defined, we use R as the result type of the closure def into which the function is translated.

Note: It would be nice generalize this further to result types which are not fully defined, yet this would complicate things by entangling typing and desugaring.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/dotty/tools/dotc/typer/Typer.scala b/src/dotty/tools/dotc/typer/Typer.scala
index 92ef0a266..c6c39f3e2 100644
--- a/src/dotty/tools/dotc/typer/Typer.scala
+++ b/src/dotty/tools/dotc/typer/Typer.scala
@@ -586,10 +586,10 @@ class Typer extends Namer with Applications with Implicits {
             cpy.ValDef(param, param.mods, param.name, paramTpt, param.rhs)
           }
 
-      /*val resultTpt =
+      val resultTpt =
         if (isFullyDefined(protoResult, ForceDegree.none)) untpd.TypeTree(protoResult)
-        else untpd.TypeTree()*/
-      typed(desugar.makeClosure(inferredParams, fnBody/*, resultTpt*/), pt)
+        else untpd.TypeTree()
+      typed(desugar.makeClosure(inferredParams, fnBody, resultTpt), pt)
     }
   }