diff --git a/src/scripting/codegeneration/codegen.cpp b/src/scripting/codegeneration/codegen.cpp
index 626dcde24..f45bea5e3 100644
--- a/src/scripting/codegeneration/codegen.cpp
+++ b/src/scripting/codegeneration/codegen.cpp
@@ -1847,8 +1847,8 @@ FxExpression *FxUnaryNotBoolean::Resolve(FCompileContext& ctx)
 
 ExpEmit FxUnaryNotBoolean::Emit(VMFunctionBuilder *build)
 {
-	assert(Operand->ValueType == ValueType);
-	assert(ValueType == TypeBool);
+	assert(Operand->ValueType == TypeBool);
+	assert(ValueType == TypeBool || IsInteger());	// this may have been changed by an int cast.
 	ExpEmit from = Operand->Emit(build);
 	assert(!from.Konst);
 	// boolean not is the same as XOR-ing the lowest bit
@@ -8069,11 +8069,10 @@ FxExpression *FxClassTypeCast::Resolve(FCompileContext &ctx)
 			{
 				if (!cls->IsDescendantOf(desttype))
 				{
-					ScriptPosition.Message(MSG_ERROR, "class '%s' is not compatible with '%s'", clsname.GetChars(), desttype->TypeName.GetChars());
-					delete this;
-					return nullptr;
+					ScriptPosition.Message(MSG_OPTERROR, "class '%s' is not compatible with '%s'", clsname.GetChars(), desttype->TypeName.GetChars());
+					cls = nullptr;
 				}
-				ScriptPosition.Message(MSG_DEBUGLOG, "resolving '%s' as class name", clsname.GetChars());
+				else ScriptPosition.Message(MSG_DEBUGLOG, "resolving '%s' as class name", clsname.GetChars());
 			}
 		}
 		FxExpression *x = new FxConstant(cls, to, ScriptPosition);
diff --git a/src/scripting/decorate/thingdef_exp.cpp b/src/scripting/decorate/thingdef_exp.cpp
index 229c8f1f4..2d69be340 100644
--- a/src/scripting/decorate/thingdef_exp.cpp
+++ b/src/scripting/decorate/thingdef_exp.cpp
@@ -477,9 +477,12 @@ static FxExpression *ParseExpression0 (FScanner &sc, PClassActor *cls)
 			exp = new FxRuntimeStateIndex(ParseExpressionM(sc, cls));
 		}
 		// The parsed expression is of type 'statelabel', but we want a real state here so we must convert it.
-		FArgumentList args;
-		args.Push(exp);
-		exp = new FxFunctionCall(NAME_ResolveState, NAME_None, args, sc);
+		if (!exp->isConstant())
+		{
+			FArgumentList args;
+			args.Push(exp);
+			exp = new FxFunctionCall(NAME_ResolveState, NAME_None, args, sc);
+		}
 		sc.MustGetToken(')');
 		return exp;
 	}