SI-7784 Allow a singleton type over a constant value defn.

When typechecking a `SingletonTypeTree`, we must `deconst`
the type of the typechecked reference tree to avoid collapsing
`a.type` into a constant type if `a` is a constant value definition.

1 files changed, 9 insertions, 0 deletions

diff --git a/test/files/pos/t7784.scala b/test/files/pos/t7784.scala
new file mode 100644
index 0000000000..4260ca26a2
--- /dev/null
+++ b/test/files/pos/t7784.scala
@@ -0,0 +1,9 @@
+object Test {
+  final val a = ""
+  var b: a.type = a
+  b = a
+
+  final val x = classOf[Object]
+  var y: x.type = x
+  y = x
+}