Refine determination of prefix in typedIdent

Author: odersky

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -268,7 +268,20 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
             if (qualifies(defDenot)) {
               val found =
                 if (isSelfDenot(defDenot)) curOwner.enclosingClass.thisType
-                else curOwner.thisType.select(name, defDenot)
+                else {
+                  val effectiveOwner =
+                    if (curOwner.isTerm && defDenot.symbol.isType)
+                      // Don't mix NoPrefix and thisType prefixes, since type comparer
+                      // would not detect types to be compatible. Note: If we replace the
+                      // 2nd condition by `defDenot.symbol.maybeOwner.isType` we get lots
+                      // of failures in the `tastyBootstrap` test. Trying to compile these
+                      // files in isolation works though.
+                      // TODO: Investigate why that happens.
+                      defDenot.symbol.owner
+                    else
+                      curOwner
+                  effectiveOwner.thisType.select(name, defDenot)
+                }
               if (!(curOwner is Package) || isDefinedInCurrentUnit(defDenot))
                 result = checkNewOrShadowed(found, definition) // no need to go further out, we found highest prec entry
               else {