Realizability refactoring

Distinguish between isStable and isRealizable.
Issue migration warnings for realizibility failures.
Provide error diagnostics why something is not realizable.

1 files changed, 8 insertions, 8 deletions

diff --git a/src/dotty/tools/dotc/core/SymDenotations.scala b/src/dotty/tools/dotc/core/SymDenotations.scala
index 3a66e10d4..fa199ab53 100644
--- a/src/dotty/tools/dotc/core/SymDenotations.scala
+++ b/src/dotty/tools/dotc/core/SymDenotations.scala
@@ -519,15 +519,15 @@ object SymDenotations {
       )
 
     /** Is this a denotation of a stable term (or an arbitrary type)? */
-    final def isStable(implicit ctx: Context) = {
-      val isUnstable =
-        (this is UnstableValue) ||
-          is(Lazy, butNot = Module) && !info.isRealizable && !hasAnnotation(defn.UncheckedStableAnnot)
-      (this is Stable) || isType || {
-        if (isUnstable) false
-        else { setFlag(Stable); true }
+    final def isStable(implicit ctx: Context) =
+      isType || !is(UnstableValue, butNot = Stable)
+
+    /** Is this a denotation of a realizable term (or an arbitrary type)? */
+    final def isRealizable(implicit ctx: Context) =
+      is(Stable) || isType || {
+        val isRealizable = !is(Lazy, butNot = Module) || info.realizability == Realizable
+        isRealizable && { setFlag(Stable); true }
       }
-    }
 
     /** Is this a "real" method? A real method is a method which is:
      *  - not an accessor