Shop Over-Availability Diagnostics

Adopt descriptive language and mention the actual availability bounds that are at issue when a declaration is more available than its enclosing scope.

Author: CodaFi

include/swift/AST/DiagnosticsSema.def

@@ -5575,10 +5575,12 @@ NOTE(note_deprecated_rename, none,
      "use '%0' instead", (StringRef))
 
 ERROR(availability_decl_more_than_enclosing, none,
-      "declaration cannot be more available than enclosing scope", ())
+      "%0 cannot be more available than enclosing scope",
+      (DescriptiveDeclKind))
 
 NOTE(availability_decl_more_than_enclosing_enclosing_here, none,
-     "enclosing scope here", ())
+     "enclosing scope requires availability of %0 %1 or newer",
+     (StringRef, llvm::VersionTuple))
 
 ERROR(availability_decl_only_version_newer, none,
       "%0 is only available in %1 %2 or newer",

lib/Sema/TypeCheckAttr.cpp

@@ -1710,9 +1710,13 @@ void AttributeChecker::visitAvailableAttr(AvailableAttr *attr) {
 
   if (EnclosingDecl) {
     if (!AttrRange.isContainedIn(EnclosingAnnotatedRange.getValue())) {
-      diagnose(attr->getLocation(), diag::availability_decl_more_than_enclosing);
+      diagnose(D->isImplicit() ? EnclosingDecl->getLoc() : attr->getLocation(),
+               diag::availability_decl_more_than_enclosing,
+               D->getDescriptiveKind());
       diagnose(EnclosingDecl->getLoc(),
-               diag::availability_decl_more_than_enclosing_enclosing_here);
+               diag::availability_decl_more_than_enclosing_enclosing_here,
+               prettyPlatformString(targetPlatform(Ctx.LangOpts)),
+               EnclosingAnnotatedRange->getOSVersion().getLowerEndpoint());
     }
   }
 

test/Sema/availability_versions.swift

@@ -615,19 +615,19 @@ class ClassAvailableOn10_9 {
 }
 
 @available(OSX, introduced: 10.51)
-class ClassAvailableOn10_51 { // expected-note {{enclosing scope here}}
+class ClassAvailableOn10_51 { // expected-note {{enclosing scope requires availability of macOS 10.51 or newer}}
   func someMethod() {}
   class func someClassMethod() {
     let _ = ClassAvailableOn10_51()
   }
   var someProp : Int = 22
 
-  @available(OSX, introduced: 10.9) // expected-error {{declaration cannot be more available than enclosing scope}}
+  @available(OSX, introduced: 10.9) // expected-error {{instance method cannot be more available than enclosing scope}}
   func someMethodAvailableOn10_9() { }
 
   @available(OSX, introduced: 10.52)
-  var propWithGetter: Int { // expected-note{{enclosing scope here}}
-    @available(OSX, introduced: 10.51) // expected-error {{declaration cannot be more available than enclosing scope}}
+  var propWithGetter: Int { // expected-note{{enclosing scope requires availability of macOS 10.52 or newer}}
+    @available(OSX, introduced: 10.51) // expected-error {{getter cannot be more available than enclosing scope}}
     get { return 0 }
   }
 }
@@ -1022,8 +1022,8 @@ extension ClassToExtend : ProtocolAvailableOn10_51 {
 }
 
 @available(OSX, introduced: 10.51)
-extension ClassToExtend { // expected-note {{enclosing scope here}}
-  @available(OSX, introduced: 10.9) // expected-error {{declaration cannot be more available than enclosing scope}}
+extension ClassToExtend { // expected-note {{enclosing scope requires availability of macOS 10.51 or newer}}
+  @available(OSX, introduced: 10.9) // expected-error {{instance method cannot be more available than enclosing scope}}
   func extensionMethod10_9() { }
 }
 

test/attr/attr_availability_osx.swift

@@ -84,11 +84,11 @@ doSomethingDeprecatedOniOS() // okay
 struct TestStruct {}
 
 @available(macOS 10.10, *)
-extension TestStruct { // expected-note {{enclosing scope here}}
+extension TestStruct { // expected-note {{enclosing scope requires availability of macOS 10.10 or newer}}
   @available(swift 400)
   func doTheThing() {} // expected-note {{'doTheThing()' was introduced in Swift 400}}
 
-  @available(macOS 10.9, *) // expected-error {{declaration cannot be more available than enclosing scope}}
+  @available(macOS 10.9, *) // expected-error {{instance method cannot be more available than enclosing scope}}
   @available(swift 400)
   func doAnotherThing() {} // expected-note {{'doAnotherThing()' was introduced in Swift 400}}