update and strengthen ~Copyable diagnostics

Author: kavon

include/swift/AST/DiagnosticsSema.def

@@ -6859,8 +6859,8 @@ ERROR(moveonly_cast,none,
       "move-only types cannot be conditionally cast", ())
 ERROR(moveonly_failable_init,none,
       "move-only types cannot have failable initializers yet", ())
-ERROR(moveonly_objc_enum_banned, none,
-      "@objc enums cannot be marked as move-only", ())
+ERROR(noncopyable_objc_enum, none,
+      "@objc enums cannot be noncopyable", ())
 
 //------------------------------------------------------------------------------
 // MARK: Conformance suppression diagnostics
@@ -6937,8 +6937,8 @@ ERROR(concurrency_task_to_thread_model_global_actor_annotation,none,
       "annotating a type with a global actor %0 is not permitted within %1",
       (TypeRepr*, StringRef))
 
-ERROR(moveOnly_not_allowed_here,none,
-      "'moveOnly' only applies to structs or enums", ())
+ERROR(noncopyable_only_struct_enum,none,
+      "only structs or enums can be noncopyable", ())
 ERROR(move_expression_not_passed_lvalue,none,
       "'consume' can only be applied to lvalues", ())
 ERROR(borrow_expression_not_passed_lvalue,none,

lib/Sema/TypeCheckAttr.cpp

@@ -2168,7 +2168,7 @@ void AttributeChecker::visitMoveOnlyAttr(MoveOnlyAttr *attr) {
        D->getASTContext().LangOpts.hasFeature(Feature::MoveOnlyClasses)))
     return;
 
-  diagnose(attr->getLocation(), diag::moveOnly_not_allowed_here)
+  diagnose(attr->getLocation(), diag::noncopyable_only_struct_enum)
     .fixItRemove(attr->getRange());
 }
 

lib/Sema/TypeCheckDecl.cpp

@@ -960,6 +960,10 @@ bool IsMoveOnlyRequest::evaluate(Evaluator &evaluator, ValueDecl *decl) const {
       return true;
   }
 
+  // At this point, we have Copyable suppressed on some type decl that isn't
+  // allowed to have it suppressed, so diagnose!
+
+  decl->diagnose(diag::noncopyable_only_struct_enum);
   return false;
 }
 

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -2666,7 +2666,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     //
 
     if (ED->isObjC() && ED->isMoveOnly()) {
-      ED->diagnose(diag::moveonly_objc_enum_banned);
+      ED->diagnose(diag::noncopyable_objc_enum);
     }
     // FIXME(kavon): see if these can be integrated into other parts of Sema
     diagnoseCopyableTypeContainingMoveOnlyType(ED);