Avoid accessing implicits that come from root imports that are hidden by some nested import.

This also changes the criterion when a root import is disabled.

A root import is now disabled if there is an inner import from the same package or module, and the inner import contains at least one disabling clause X => _. (The latter crierion is new; without it, we would consider something like

     import scala.{collections => c}

as a hiding import for Scala, which seems to go too far.)

1 files changed, 2 insertions, 5 deletions

diff --git a/src/dotty/tools/dotc/typer/Typer.scala b/src/dotty/tools/dotc/typer/Typer.scala
index 9ae8252a1..aad03c47c 100644
--- a/src/dotty/tools/dotc/typer/Typer.scala
+++ b/src/dotty/tools/dotc/typer/Typer.scala
@@ -185,11 +185,8 @@ class Typer extends Namer with Applications with Implicits {
      *  import in the same program?
      */
     def isDisabled(imp: ImportInfo, site: Type): Boolean = {
-      val qualSym = site.termSymbol
-      if (defn.RootImports contains qualSym) {
-        if (imp.isRootImport && (importedFromRoot contains qualSym)) return true
-        importedFromRoot += qualSym
-      }
+      if (imp.isRootImport && (importedFromRoot contains site.termSymbol)) return true
+      if (imp.hiddenRoot.exists) importedFromRoot += imp.hiddenRoot
       false
     }