diff --git a/src/thingdef/thingdef_exp.cpp b/src/thingdef/thingdef_exp.cpp
index 35932e0be..6a756d9b5 100644
--- a/src/thingdef/thingdef_exp.cpp
+++ b/src/thingdef/thingdef_exp.cpp
@@ -392,7 +392,7 @@ static FxExpression *ParseExpression0 (FScanner &sc, PClassActor *cls)
 				return ParseAtan2(sc, identifier, cls);
 			default:
 				args = new FArgumentList;
-				func = dyn_cast<PFunction>(cls->Symbols.FindSymbol(identifier, true));
+				func = (cls == nullptr) ? nullptr : dyn_cast<PFunction>(cls->Symbols.FindSymbol(identifier, true));
 				try
 				{
 					// There is an action function ACS_NamedExecuteWithResult which must be ignored here for this to work.
diff --git a/src/thingdef/thingdef_expression.cpp b/src/thingdef/thingdef_expression.cpp
index acb26d05b..fee31a6e9 100644
--- a/src/thingdef/thingdef_expression.cpp
+++ b/src/thingdef/thingdef_expression.cpp
@@ -4410,6 +4410,8 @@ ExpEmit FxClassTypeCast::Emit(VMFunctionBuilder *build)
 FxExpression *FxStateByIndex::Resolve(FCompileContext &ctx)
 {
 	CHECKRESOLVED();
+	ABORT(ctx.Class);
+
 	if (ctx.Class->NumOwnedStates == 0)
 	{
 		// This can't really happen
@@ -4464,6 +4466,8 @@ FxMultiNameState::FxMultiNameState(const char *_statestring, const FScriptPositi
 FxExpression *FxMultiNameState::Resolve(FCompileContext &ctx)
 {
 	CHECKRESOLVED();
+	ABORT(ctx.Class);
+
 	if (names[0] == NAME_None)
 	{
 		scope = NULL;