Fix treatment of by name functions

By-name functions like `(=> T) => T` were not treated correctly before.
Witness the disabled `-Ycheck:gettersSetters` for transform/TreeCheckers
in thge test suite. This commit changes the scheme how => T types are treated
and fixes the problems with by-name functions.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/transform/TreeChecker.scala b/src/dotty/tools/dotc/transform/TreeChecker.scala
index 4a7d280e5..e09a83a04 100644
--- a/src/dotty/tools/dotc/transform/TreeChecker.scala
+++ b/src/dotty/tools/dotc/transform/TreeChecker.scala
@@ -196,7 +196,7 @@ class TreeChecker {
           !pt.isInstanceOf[FunProto])
         assert(tree.tpe <:< pt,
             s"error at ${sourcePos(tree.pos)}\n" +
-            err.typeMismatchStr(tree.tpe, pt) + "tree = " + tree)
+            err.typeMismatchStr(tree.tpe, pt) + "\ntree = " + tree)
       tree
     }
   }