[tests] add test for #7282

tests/server/src/cases/issues/Issue7282.hx

@@ -0,0 +1,13 @@
+package cases.issues;
+
+class Issue7282 extends TestCase {
+	function test(_) {
+		vfs.putContent("Main.hx", getTemplate("issues/Issue7282/Main.hx"));
+		var args = ["-main", "Main"];
+		runHaxe(args);
+		assertSuccess();
+		runHaxeJsonCb(args, DisplayMethods.Diagnostics, {file: new FsPath("Main.hx")}, res -> {
+			Assert.equals("Unused variable", (cast res[0].diagnostics[0].args).description);
+		});
+	}
+}

tests/server/test/templates/issues/Issue7282/Main.hx

@@ -0,0 +1,10 @@
+import haxe.ds.Option;
+
+class Main {
+	public static function main() {
+		switch ((null:Option<Int>)) {
+			case Some(value):
+			case None:
+		}
+	}
+}