Sema: Minor improvements to access_control_non_objc_open_member message

* Use the '%kindonly' specifier.
* Make the object and its modifier agree on grammatical number.
* 'in extension' → 'declared in extension'.

Author: AnthonyLatsis

include/swift/AST/DiagnosticsSema.def

@@ -2177,8 +2177,9 @@ ERROR(access_control_open_bad_decl,none,
       "only classes and overridable class members can be declared 'open';"
       " use 'public'", ())
 ERROR(access_control_non_objc_open_member,none,
-      "non-'@objc' %0 in extensions cannot be overridden; use 'public' instead",
-      (DescriptiveDeclKind))
+      "non-'@objc' %kindonly0 declared in extension cannot be overridden; use "
+      "'public' instead",
+      (const ValueDecl *))
 ERROR(access_control_requires_package_name, none,
       "the package access level %select{|used on %1 }0"
       "requires a package name; set it with the compiler flag -package-name",

lib/Sema/TypeCheckAttr.cpp

@@ -1327,8 +1327,7 @@ void AttributeChecker::visitAccessControlAttr(AccessControlAttr *attr) {
           // an extension.
           if (!VD->isObjC() && attr->getAccess() == AccessLevel::Open) {
             diagnose(attr->getLocation(),
-                     diag::access_control_non_objc_open_member,
-                     VD->getDescriptiveKind())
+                     diag::access_control_non_objc_open_member, VD)
                 .fixItReplace(attr->getRange(), "public")
                 .warnUntilSwiftVersion(7);
           }

test/attr/open_objc.swift

@@ -9,11 +9,11 @@ open class InvalidOpenExtension {
   open var openVar: Int { 3 } // No warning: Pure Swift properties can be open inside the class declaration.
 }
 extension InvalidOpenExtension {
-  open func nonObjcOpenMethod() { } // expected-warning {{non-'@objc' instance method in extensions cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}} {{3-7=public}}
-  open class func nonObjcOpenMethod() { } // expected-warning {{non-'@objc' class method in extensions cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}} {{3-7=public}}
-  open var nonObjcOpenVar: Int { 3 }  // expected-warning {{non-'@objc' property in extensions cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}} {{3-7=public}}
-  open subscript(_ index: Int) -> Int { 3 } // expected-warning {{non-'@objc' subscript in extensions cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}} {{3-7=public}}
-  open convenience init(index: Int) { self.init() } // expected-error {{only classes and overridable class members can be declared 'open'; use 'public'}} // expected-warning {{non-'@objc' initializer in extensions cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}}
+  open func nonObjcOpenMethod() { } // expected-warning {{non-'@objc' instance method declared in extension cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}} {{3-7=public}}
+  open class func nonObjcOpenMethod() { } // expected-warning {{non-'@objc' class method declared in extension cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}} {{3-7=public}}
+  open var nonObjcOpenVar: Int { 3 }  // expected-warning {{non-'@objc' property declared in extension cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}} {{3-7=public}}
+  open subscript(_ index: Int) -> Int { 3 } // expected-warning {{non-'@objc' subscript declared in extension cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}} {{3-7=public}}
+  open convenience init(index: Int) { self.init() } // expected-error {{only classes and overridable class members can be declared 'open'; use 'public'}} // expected-warning {{non-'@objc' initializer declared in extension cannot be overridden; use 'public' instead; this will be an error in a future Swift language mode}}
 
   @objc open func objcOpenMethod() { } // No warning: @objc methods can be open inside extensions. 
   @objc open var objcOpenVar: Int { 3 } // No warning: @objc methods can be open inside extensions.