diff --git a/src/script_opt/CPP/RuntimeOps.cc b/src/script_opt/CPP/RuntimeOps.cc
index b74ac496e7..28fdea66d9 100644
--- a/src/script_opt/CPP/RuntimeOps.cc
+++ b/src/script_opt/CPP/RuntimeOps.cc
@@ -105,7 +105,7 @@ ValPtr when_invoke__CPP(Func* f, std::vector<ValPtr> args, Frame* frame, void* c
 
 	auto res = f->Invoke(&args, frame);
 	if ( ! res )
-		throw DelayedCallException();
+		throw CPPDelayedCallException();
 
 	return res;
 	}
diff --git a/src/script_opt/CPP/RuntimeOps.h b/src/script_opt/CPP/RuntimeOps.h
index 8ed8622941..9573e0b3fd 100644
--- a/src/script_opt/CPP/RuntimeOps.h
+++ b/src/script_opt/CPP/RuntimeOps.h
@@ -80,7 +80,7 @@ inline ValPtr invoke__CPP(Func* f, std::vector<ValPtr> args, Frame* frame)
 extern ValPtr when_invoke__CPP(Func* f, std::vector<ValPtr> args, Frame* frame, void* caller_addr);
 
 // Thrown when a call inside a "when" delays.
-class DelayedCallException : public InterpreterException
+class CPPDelayedCallException : public InterpreterException
 	{
 	};
 
diff --git a/src/script_opt/CPP/Stmts.cc b/src/script_opt/CPP/Stmts.cc
index ff215bceee..b9666573a3 100644
--- a/src/script_opt/CPP/Stmts.cc
+++ b/src/script_opt/CPP/Stmts.cc
@@ -446,7 +446,7 @@ void CPPCompile::GenWhenStmt(const WhenStmt* w)
 		{
 		Emit("ValPtr retval = {NewRef{}, curr_t->Lookup(curr_assoc)};");
 		Emit("if ( ! retval )");
-		Emit("\tthrow DelayedCallException();");
+		Emit("\tthrow CPPDelayedCallException();");
 		Emit("return %s;", GenericValPtrToGT("retval", ret_type, GEN_NATIVE));
 		}