Workaround #1895: Bringing a symbol to a new run is broken

Author: smarter

compiler/src/dotty/tools/dotc/core/SymDenotations.scala

@@ -45,9 +45,13 @@ trait SymDenotations { this: Context =>
     else {
       val initial = denot.initial
       val firstPhaseId = initial.validFor.firstPhaseId.max(ctx.typerPhase.id)
-      if ((initial ne denot) || ctx.phaseId != firstPhaseId)
-        ctx.withPhase(firstPhaseId).stillValidInOwner(initial)
-      else
+     if ((initial ne denot) || ctx.phaseId != firstPhaseId) {
+       ctx.withPhase(firstPhaseId).stillValidInOwner(initial) ||
+         // Workaround #1895: A symbol might not be entered into an owner
+         // until the second phase where it exists
+         (denot.validFor.containsPhaseId(firstPhaseId + 1)) &&
+           ctx.withPhase(firstPhaseId + 1).stillValidInOwner(initial)
+      } else
         stillValidInOwner(denot)
     }
 

compiler/src/dotty/tools/dotc/transform/ExtensionMethods.scala

@@ -63,8 +63,13 @@ class ExtensionMethods extends MiniPhaseTransform with DenotTransformer with Ful
             // not generate them again.
             if (!(valueClass is Scala2x)) ctx.atPhase(thisTransformer) { implicit ctx =>
               for (decl <- valueClass.classInfo.decls) {
-                if (isMethodWithExtension(decl))
-                  decls1.enter(createExtensionMethod(decl, moduleClassSym.symbol))
+                if (isMethodWithExtension(decl)) {
+                  val meth = createExtensionMethod(decl, moduleClassSym.symbol)
+                  decls1.enter(meth)
+                  // Workaround #1895: force denotation of `meth` to be
+                  // at phase where `meth` is entered into the decls of a class
+                  meth.denot(ctx.withPhase(thisTransformer.next))
+                }
               }
             }
 

tests/repl/vc.check

@@ -0,0 +1,5 @@
+scala> class Foo(x: Int) extends AnyVal { def hi: Int = 1 }
+defined class Foo
+scala> new Foo(1).hi
+val res0: Int = 1
+scala> :quit