Take environment into account when typing a closure.

Environment parameters do not count in th eresult type.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/dotty/tools/dotc/core/Types.scala b/src/dotty/tools/dotc/core/Types.scala
index 529452c73..6145bdffb 100644
--- a/src/dotty/tools/dotc/core/Types.scala
+++ b/src/dotty/tools/dotc/core/Types.scala
@@ -906,10 +906,14 @@ object Types {
 
     /** Turn type into a function type.
      *  @pre this is a non-dependent method type.
+     *  @param drop  The number of trailing parameters that should be dropped
+     *               when forming the function type.
      */
-    def toFunctionType(implicit ctx: Context): Type = this match {
+    def toFunctionType(dropLast: Int = 0)(implicit ctx: Context): Type = this match {
       case mt @ MethodType(_, formals) if !mt.isDependent =>
-        defn.FunctionType(formals mapConserve (_.underlyingIfRepeated(mt.isJava)), mt.resultType)
+        val formals1 = if (dropLast == 0) formals else formals dropRight dropLast
+        defn.FunctionType(
+            formals1 mapConserve (_.underlyingIfRepeated(mt.isJava)), mt.resultType)
     }
 
     /** The signature of this type. This is by default NotAMethod,