Make literalize work for TermRefs of constant type.

2 files changed, 8 insertions, 5 deletions

diff --git a/src/dotty/tools/dotc/core/Types.scala b/src/dotty/tools/dotc/core/Types.scala
index 0e9f5d9b2..5fd3b81d0 100644
--- a/src/dotty/tools/dotc/core/Types.scala
+++ b/src/dotty/tools/dotc/core/Types.scala
@@ -94,9 +94,8 @@ object Types {
     /** Does this type denote a stable reference (i.e. singleton type)? */
     final def isStable(implicit ctx: Context): Boolean = stripTypeVar match {
       case tp: TermRef => tp.termSymbol.isStable && tp.prefix.isStable
-      case _: SingletonType => true
+      case _: SingletonType | NoPrefix => true
       case tp: RefinedType => tp.parent.isStable
-      case NoPrefix => true
       case _ => false
     }
 
diff --git a/src/dotty/tools/dotc/transform/Literalize.scala b/src/dotty/tools/dotc/transform/Literalize.scala
index 4a223e912..f33baa52b 100644
--- a/src/dotty/tools/dotc/transform/Literalize.scala
+++ b/src/dotty/tools/dotc/transform/Literalize.scala
@@ -51,9 +51,13 @@ class Literalize extends MiniPhaseTransform { thisTransform =>
    *  Revisit this issue once we have implemented `inline`. Then we can demand
    *  purity of the prefix unless the selection goes to an inline val.
    */
-  def literalize(tree: Tree)(implicit ctx: Context): Tree = tree.tpe match {
-    case ConstantType(value) if isIdempotentExpr(tree) => Literal(value)
-    case _ => tree
+  def literalize(tree: Tree)(implicit ctx: Context): Tree = {
+    def recur(tp: Type): Tree = tp match {
+      case ConstantType(value) if isIdempotentExpr(tree) => Literal(value)
+      case tp: TermRef if tp.symbol.isStable => recur(tp.info.widenExpr)
+      case _ => tree
+    }
+    recur(tree.tpe)
   }
 
   override def transformIdent(tree: Ident)(implicit ctx: Context, info: TransformerInfo): Tree =