diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 142070884d..eab989a0ab 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -4572,12 +4572,17 @@ fn (mut g Gen) interface_table() string {
 		cast_functions.write('// Casting functions for interface "$interface_name"')
 		mut methods_wrapper := strings.new_builder(100)
 		methods_wrapper.writeln('// Methods wrapper for interface "$interface_name"')
+		mut already_generated_mwrappers := map[string]bool
 		for i, st in inter_info.types {
 			// cctype is the Cleaned Concrete Type name, *without ptr*,
 			// i.e. cctype is always just Cat, not Cat_ptr:
 			cctype := g.cc_type(st)
 			// Speaker_Cat_index = 0
 			interface_index_name := '_${interface_name}_${cctype}_index'
+			if already_generated_mwrappers[interface_index_name] {
+				continue
+			}
+			already_generated_mwrappers[interface_index_name] = true
 			cast_functions.writeln('
 _Interface I_${cctype}_to_Interface_${interface_name}($cctype* x) {
 	return (_Interface) {