Fix #7013: Check PCP for all class references

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

@@ -138,8 +138,12 @@ class PCPCheckAndHeal(@constructorOnly ictx: Context) extends TreeMapWithStages(
     /** Is a reference to a class but not `this.type` */
     def isClassRef = sym.isClass && !tp.isInstanceOf[ThisType]
 
-    if (sym.exists && !sym.isStaticOwner && !isClassRef && !levelOK(sym))
+    if (!sym.exists || levelOK(sym))
+      None
+    else if (!sym.isStaticOwner && !isClassRef)
       tryHeal(sym, tp, pos)
+    else if (!sym.owner.isStaticOwner) // non-top level class reference that is phase inconsistent
+      levelError(sym, tp, pos, "")
     else
       None
   }
@@ -170,17 +174,6 @@ class PCPCheckAndHeal(@constructorOnly ictx: Context) extends TreeMapWithStages(
    *                    to be added to the "inconsistent phase" message.
    */
   protected def tryHeal(sym: Symbol, tp: Type, pos: SourcePosition)(implicit ctx: Context): Option[Tree] = {
-    def levelError(errMsg: String) = {
-      def symStr =
-        if (!tp.isInstanceOf[ThisType]) sym.show
-        else if (sym.is(ModuleClass)) sym.sourceModule.show
-        else i"${sym.name}.this"
-      ctx.error(
-        em"""access to $symStr from wrong staging level:
-            | - the definition is at level ${levelOf(sym).getOrElse(0)},
-            | - but the access is at level $level.$errMsg""", pos)
-      None
-    }
     tp match {
       case tp: TypeRef =>
         if (level == -1) {
@@ -193,19 +186,33 @@ class PCPCheckAndHeal(@constructorOnly ictx: Context) extends TreeMapWithStages(
             case _: TermRef =>
               Some(tag.select(tpnme.splice))
             case _: SearchFailureType =>
-              levelError(i"""
+              levelError(sym, tp, pos,
+                         i"""
                             |
                             | The access would be accepted with the right type tag, but
                             | ${ctx.typer.missingArgMsg(tag, reqType, "")}""")
             case _ =>
-              levelError(i"""
+              levelError(sym, tp, pos,
+                         i"""
                             |
                             | The access would be accepted with an implict $reqType""")
           }
         }
       case _ =>
-        levelError("")
+        levelError(sym, tp, pos, "")
     }
   }
 
+  private def levelError(sym: Symbol, tp: Type, pos: SourcePosition, errMsg: String) given Context = {
+    def symStr =
+      if (!tp.isInstanceOf[ThisType]) sym.show
+      else if (sym.is(ModuleClass)) sym.sourceModule.show
+      else i"${sym.name}.this"
+    the[Context].error(
+      em"""access to $symStr from wrong staging level:
+          | - the definition is at level ${levelOf(sym).getOrElse(0)},
+          | - but the access is at level $level.$errMsg""", pos)
+    None
+  }
+
 }

tests/neg/i7013.scala

@@ -0,0 +1,6 @@
+import quoted._
+
+def foo() given QuoteContext = {
+  class C
+  '[C] // error
+}

tests/neg/i7013b.scala

@@ -0,0 +1,8 @@
+import quoted._
+
+class Foo {
+  class Bar
+  def foo() given QuoteContext = {
+    '[Bar] // error
+  }
+}

tests/neg/i7013c.scala

@@ -0,0 +1,6 @@
+import quoted._
+
+def foo() given QuoteContext = {
+  type C
+  '[C] // error
+}