Fix --fatal-deprecation adding obsolete ones

See also #2647

Author: halo

lib/src/deprecation.dart

@@ -224,7 +224,8 @@ enum Deprecation {
     var range = VersionRange(max: version, includeMax: true);
     return {
       for (var deprecation in Deprecation.values)
-        if (deprecation.deprecatedIn.andThen(range.allows) ?? false)
+        if ((deprecation.deprecatedIn.andThen(range.allows) ?? false) &&
+            deprecation.obsoleteIn == null)
           deprecation,
     };
   }

test/deprecations_test.dart

@@ -8,6 +8,7 @@ library;
 import 'package:test/test.dart';
 
 import 'package:sass/sass.dart';
+import 'package:pub_semver/pub_semver.dart';
 
 void main() {
   // Deprecated in all version of Dart Sass
@@ -151,6 +152,39 @@ void main() {
       );
     });
   });
+
+  group('Deprecation.forVersion', () {
+    test('excludes deprecations that are obsolete', () {
+      final version = Version.parse('1.79.0');
+      final deprecations = Deprecation.forVersion(version);
+
+      expect(
+        deprecations,
+        equals({
+          Deprecation.callString,
+          Deprecation.elseif,
+          Deprecation.mozDocument,
+          Deprecation.relativeCanonical,
+          Deprecation.newGlobal,
+          Deprecation.colorModuleCompat,
+          Deprecation.slashDiv,
+          Deprecation.bogusCombinators,
+          Deprecation.strictUnary,
+          Deprecation.functionUnits,
+          Deprecation.duplicateVarFlags,
+          Deprecation.nullAlpha,
+          Deprecation.absPercent,
+          Deprecation.fsImporterCwd,
+          Deprecation.cssFunctionMixin,
+          Deprecation.featureExists,
+          Deprecation.color4Api,
+          Deprecation.colorFunctions,
+          Deprecation.legacyJsApi
+        }),
+        reason: 'mixed-decls obsolete as of 1.92.0',
+      );
+    });
+  });
 }
 
 /// Confirms that [source] will error if [deprecation] is fatal.