diff --git a/IDEHelper/Compiler/CeMachine.cpp b/IDEHelper/Compiler/CeMachine.cpp
index 97bcdf12..26426ba2 100644
--- a/IDEHelper/Compiler/CeMachine.cpp
+++ b/IDEHelper/Compiler/CeMachine.cpp
@@ -4911,7 +4911,11 @@ BfTypedValue CeContext::Call(CeCallSource callSource, BfModule* module, BfMethod
 
 		if (!isConst)
 		{
-			if ((argIdx != thisArgIdx) && (argIdx != appendAllocIdx))
+			if ((argIdx == thisArgIdx) && (methodInstance->mMethodDef->mMethodType == BfMethodType_Ctor))
+			{
+				// Allow non-const 'this' for ctor
+			}
+			else if (argIdx != appendAllocIdx)
 			{
 				Fail(StrFormat("Non-constant argument for param '%s'", methodInstance->GetParamName(paramIdx).c_str()));
 				return BfTypedValue();
diff --git a/IDEHelper/Tests/src/Comptime.bf b/IDEHelper/Tests/src/Comptime.bf
index 2b2b418c..80c32d30 100644
--- a/IDEHelper/Tests/src/Comptime.bf
+++ b/IDEHelper/Tests/src/Comptime.bf
@@ -220,7 +220,7 @@ namespace Tests
 
 				String serializeBuffer = new .();
 
-				Compiler.Assert(!type.IsUnion);
+				Runtime.Assert(!type.IsUnion);
 
 				for (let field in type.GetFields())
 				{