Handle O.this outside of it's definition

compiler/src/dotty/tools/dotc/transform/init/Semantic.scala

@@ -868,8 +868,11 @@ class Semantic {
         cases(tmref.prefix, thisV, klass, source).select(tmref.symbol, source)
 
       case tp @ ThisType(tref) =>
-        val value = resolveThis(tref.classSymbol.asClass, thisV, klass, source)
-        Result(value, Errors.empty)
+        val cls = tref.classSymbol.asClass
+        if cls.isStaticOwner && !klass.isContainedIn(cls) then Result(Hot, Nil)
+        else
+          val value = resolveThis(cls, thisV, klass, source)
+          Result(value, Errors.empty)
 
       case _: TermParamRef | _: RecThis  =>
         // possible from checking effects of types
@@ -890,7 +893,12 @@ class Semantic {
         case addr: Addr =>
           val obj = heap(addr)
           val outerCls = klass.owner.enclosingClass.asClass
-          resolveThis(target, obj.outers(klass), outerCls, source)
+          if !obj.outers.contains(klass) then
+            val error = PromoteError("outer not yet initialized, target = " + target + ", klass = " + klass, source, trace.toVector)
+            report.error(error.show + error.stacktrace, source)
+            Hot
+          else
+            resolveThis(target, obj.outers(klass), outerCls, source)
         case RefSet(refs) =>
           refs.map(ref => resolveThis(target, ref, klass, source)).join
         case fun: Fun =>

tests/init/pos/Parsers.scala

@@ -0,0 +1,10 @@
+object Parsers {
+  enum Location(val inParens: Boolean, val inPattern: Boolean, val inArgs: Boolean):
+    case InParens      extends Location(true, false, false)
+    case InArgs        extends Location(true, false, true)
+    case InPattern     extends Location(false, true, false)
+    case InGuard       extends Location(false, false, false)
+    case InPatternArgs extends Location(false, true, true) // InParens not true, since it might be an alternative
+    case InBlock       extends Location(false, false, false)
+    case ElseWhere     extends Location(false, false, false)
+}