diff --git a/src/newgrf_industries.h b/src/newgrf_industries.h
--- a/src/newgrf_industries.h
+++ b/src/newgrf_industries.h
@@ -21,7 +21,7 @@ struct IndustriesScopeResolver : public 
 	IndustryType type;  ///< Type of the industry.
 	uint32 random_bits; ///< Random bits of the new industry.
 
-	IndustriesScopeResolver(ResolverObject *ro, TileIndex tile, Industry *industry, IndustryType type, uint32 random_bits = 0);
+	IndustriesScopeResolver(ResolverObject &ro, TileIndex tile, Industry *industry, IndustryType type, uint32 random_bits = 0);
 
 	/* virtual */ uint32 GetRandomBits() const;
 	/* virtual */ uint32 GetVariable(byte variable, uint32 parameter, bool *available) const;