diff --git a/src/terraform_gui.cpp b/src/terraform_gui.cpp
--- a/src/terraform_gui.cpp
+++ b/src/terraform_gui.cpp
@@ -500,8 +500,7 @@ static void ResetLandscapeConfirmationCa
 		_generating_world = true;
 
 		/* Delete all companies */
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			ChangeOwnershipOfCompanyItems(c->index, INVALID_OWNER);
 			delete c;
 		}