Better job of stripping module class names

The lack of this caused a spurious pickling error in i11914a.scala when proxy
generation changed.

Author: odersky

compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala

@@ -78,9 +78,10 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
   }
 
   override def nameString(name: Name): String =
-    if ctx.settings.YdebugNames.value then name.debugString
+    def strippedName = if printDebug then name else name.stripModuleClassSuffix
+    if ctx.settings.YdebugNames.value then strippedName.debugString
     else if name.isTypeName && name.is(WildcardParamName) && !printDebug then "_"
-    else super.nameString(name)
+    else super.nameString(strippedName)
 
   override protected def simpleNameString(sym: Symbol): String =
     nameString(if (ctx.property(XprintMode).isEmpty) sym.initial.name else sym.name)

tests/neg/exports.check

@@ -11,7 +11,7 @@
 25 |    export printUnit.bitmap         // error: no eligible member
    |                     ^
    |                     non-private given instance bitmap in class Copier refers to private value printUnit
-   |                     in its type signature => Copier.this.printUnit.bitmap$
+   |                     in its type signature => Copier.this.printUnit.bitmap
 -- [E120] Naming Error: tests/neg/exports.scala:23:33 ------------------------------------------------------------------
 23 |    export printUnit.{stat => _, _} // error: double definition
    |                                 ^