Diags: say "actors" cannot be ~Copyable

rdar://130450351
(cherry picked from commit 05f5e51)

Author: kavon

include/swift/AST/DiagnosticsSema.def

@@ -7672,8 +7672,8 @@ ERROR(inverse_associatedtype_restriction, none,
       "cannot suppress '%0' requirement of an associated type",
       (StringRef))
 ERROR(inverse_on_class, none,
-      "classes cannot be '~%0'",
-      (StringRef))
+      "%select{classes|actors}1 cannot be '~%0'",
+      (StringRef, bool))
 ERROR(inverse_with_class_constraint, none,
       "composition involving %select{class requirement %2|'AnyObject'}0 "
       "cannot contain '~%1'",

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -3345,7 +3345,8 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
       ctx.Diags.diagnose(decl->getLoc(),
                          diag::inverse_on_class,
-                         getProtocolName(getKnownProtocolKind(ip)));
+                         getProtocolName(getKnownProtocolKind(ip)),
+                         decl->isAnyActor());
     }
   }
 

test/Generics/inverse_classes2.swift

@@ -1,13 +1,12 @@
-// RUN: %target-typecheck-verify-swift \
-// RUN:   -parse-stdlib -module-name Swift
-
-// NOTE: -parse-stdlib is a transitional workaround and should not be required.
+// RUN: %target-typecheck-verify-swift -disable-availability-checking
 
 @_moveOnly // expected-error {{'@_moveOnly' attribute is only valid on structs or enums}}
 class KlassLegacy {}
 
 class KlassModern: ~Copyable {} // expected-error {{classes cannot be '~Copyable'}}
 
+actor FamousPerson: ~Copyable {} // expected-error{{actors cannot be '~Copyable'}}
+
 class Konditional<T: ~Copyable> {}
 
 func checks<T: ~Copyable, C>(