Don't constrain to swift-version 5

Author: aschwaighofer

include/swift/AST/DiagnosticsSema.def

@@ -3874,9 +3874,6 @@ ERROR(borrowed_on_objc_protocol_requirement,none,
 
 ERROR(dynamic_not_in_class,none,
       "only members of classes may be dynamic", ())
-ERROR(dynamic_with_final,none,
-      "a declaration cannot be both 'final' and 'dynamic'",
-      ())
 ERROR(dynamic_with_nonobjc,none,
       "a declaration cannot be both '@nonobjc' and 'dynamic'",
       ())

lib/Sema/TypeCheckAttr.cpp

@@ -323,13 +323,6 @@ void AttributeEarlyChecker::visitMutationAttr(DeclAttribute *attr) {
 }
 
 void AttributeEarlyChecker::visitDynamicAttr(DynamicAttr *attr) {
-  // Members cannot be both dynamic and final.
-  // We do allow dynamic final members for dynamic replacement in
-  // swift-version 5.
-  if (D->getAttrs().hasAttribute<FinalAttr>() &&
-      !D->getASTContext().LangOpts.isSwiftVersionAtLeast(5))
-    diagnoseAndRemoveAttr(attr, diag::dynamic_with_final);
-
   // Members cannot be both dynamic and @nonobjc.
   if (D->getAttrs().hasAttribute<NonObjCAttr>())
     diagnoseAndRemoveAttr(attr, diag::dynamic_with_nonobjc);
@@ -2593,11 +2586,6 @@ void TypeChecker::addImplicitDynamicAttribute(Decl *D) {
       isa<AccessorDecl>(D))
     return;
 
-  // Don't add implicit dynamic to final functions before swift-version 5.
-  if (D->getAttrs().hasAttribute<FinalAttr>() &&
-      !D->getASTContext().LangOpts.isSwiftVersionAtLeast(5))
-    return;
-
   if (D->getAttrs().hasAttribute<NonObjCAttr>() ||
       D->getAttrs().hasAttribute<TransparentAttr>() ||
       D->getAttrs().hasAttribute<InlinableAttr>())

test/attr/attr_dynamic.swift

@@ -34,7 +34,7 @@ class Foo {
 
   func notDynamic() {}
 
-  @objc final dynamic func indecisive() {} // expected-error{{a declaration cannot be both 'final' and 'dynamic'}} {{15-23=}}
+  @objc final dynamic func indecisive() {}
 }
 
 struct Bar {