LLVM and the relevant Visual Studio version and giving me quite the conniption

appveyor.yml

@@ -59,6 +59,8 @@ matrix:
   allow_failures:
     # 32-bit builds are temperamental with exceptions
     - platform: x86
+    # LLVM is experimental as all get-out
+    - LLVM_VERSION: 4.0.0
   exclude:
     # Necessary: MinGW doesn't exist on VS 2017 images
     - image: Visual Studio 2017

tests/test_plain_types.cpp

@@ -29,11 +29,11 @@
 
 TEST_CASE("plain/alignment", "test that aligned classes in certain compilers don't trigger compiler errors") {
 #ifdef _MSC_VER
-	__declspec(align(16)) class aligned_class {
+	__declspec(align(16)) struct aligned_class {
 		int var;
 	};
 
-	class A {
+	struct A {
 		aligned_class a;
 	};