Update availability diagnostic for macOS major version number changes

Resolves: #57419

Author: cbjeukendrup

lib/Sema/TypeCheckAvailability.cpp

@@ -1881,19 +1881,19 @@ static bool fixAvailabilityByNarrowingNearbyVersionCheck(
                                  AvailabilityContext(RunningRange))) {
 
     // Only fix situations that are "nearby" versions, meaning
-    // disagreement on a minor-or-less version for non-macOS,
-    // or disagreement on a subminor-or-less version for macOS.
+    // disagreement on a subminor-or-less version for macOS 10,
+    // or disagreement on a minor-or-less version otherwise.
     auto RunningVers = RunningRange.getLowerEndpoint();
     auto RequiredVers = RequiredRange.getLowerEndpoint();
     auto Platform = targetPlatform(Context.LangOpts);
     if (RunningVers.getMajor() != RequiredVers.getMajor())
       return false;
     if ((Platform == PlatformKind::macOS ||
          Platform == PlatformKind::macOSApplicationExtension) &&
+        RunningVers.getMajor() == 10 &&
         !(RunningVers.getMinor().has_value() &&
           RequiredVers.getMinor().has_value() &&
-          RunningVers.getMinor().value() ==
-          RequiredVers.getMinor().value()))
+          RunningVers.getMinor().value() == RequiredVers.getMinor().value()))
       return false;
 
     auto FixRange = TRC->getAvailabilityConditionVersionSourceRange(

test/Sema/availability_versions_multi.swift

@@ -32,19 +32,16 @@ func useFromOtherOn99_51() {
 
   let o10_9 = OtherIntroduced10_9()
   o10_9.extensionMethodOnOtherIntroduced10_9AvailableOn99_51(o99_51)
-  _ = o99_51.returns99_52Introduced99_52() // expected-error {{'returns99_52Introduced99_52()' is only available in macOS 99.52 or newer}}
-      // expected-note@-1 {{add 'if #available' version check}}
+  _ = o99_51.returns99_52Introduced99_52() // expected-error {{'returns99_52Introduced99_52()' is only available in macOS 99.52 or newer}} {{26:29-34=99.52}}
 
   _ = OtherIntroduced99_52()
-      // expected-error@-1 {{'OtherIntroduced99_52' is only available in macOS 99.52 or newer}}
-      // expected-note@-2 {{add 'if #available' version check}}
+      // expected-error@-1 {{'OtherIntroduced99_52' is only available in macOS 99.52 or newer}} {{26:29-34=99.52}}
 
-  o99_51.extensionMethodOnOtherIntroduced99_51AvailableOn99_52() // expected-error {{'extensionMethodOnOtherIntroduced99_51AvailableOn99_52()' is only available in macOS 99.52 or newer}}
-      // expected-note@-1 {{add 'if #available' version check}}
+  o99_51.extensionMethodOnOtherIntroduced99_51AvailableOn99_52() 
+      // expected-error@-1 {{'extensionMethodOnOtherIntroduced99_51AvailableOn99_52()' is only available in macOS 99.52 or newer}} {{26:29-34=99.52}}
 
   _ = OtherIntroduced99_51.NestedIntroduced99_52()
-      // expected-error@-1 {{'NestedIntroduced99_52' is only available in macOS 99.52 or newer}}
-      // expected-note@-2 {{add 'if #available' version check}}
+      // expected-error@-1 {{'NestedIntroduced99_52' is only available in macOS 99.52 or newer}} {{26:29-34=99.52}}
 }
 
 @available(OSX, introduced: 99.52)
@@ -53,8 +50,7 @@ func useFromOtherOn99_52() {
 
   let n99_52 = OtherIntroduced99_51.NestedIntroduced99_52()
   _ = n99_52.returns99_52()
-  _ = n99_52.returns99_53() // expected-error {{'returns99_53()' is only available in macOS 99.53 or newer}}
-      // expected-note@-1 {{add 'if #available' version check}}
+  _ = n99_52.returns99_53() // expected-error {{'returns99_53()' is only available in macOS 99.53 or newer}} {{47:29-34=99.53}}
 
   // This will trigger validation of the global in availability_in_multi_other.swift
   _ = globalFromOtherOn99_52