table: fix generic method with multi generic types (#12297)

vlib/v/ast/table.v

@@ -1690,8 +1690,10 @@ pub fn (mut t Table) generic_insts_to_concrete() {
 
 						parent_sym := t.get_type_symbol(parent_info.parent_type)
 						for method in parent_sym.methods {
+							if method.generic_names.len == info.concrete_types.len {
 								t.register_fn_concrete_types(method.name, info.concrete_types)
 							}
+						}
 					} else {
 						util.verror('generic error', 'the number of generic types of struct `$parent.name` is inconsistent with the concrete types')
 					}

vlib/v/tests/generics_method_with_multi_types_test.v

@@ -0,0 +1,30 @@
+interface Something {
+	i int
+}
+
+struct Some {
+	i int
+}
+
+struct App<M> {
+	f M
+}
+
+fn (mut self App<M>) next<M, T>(input T) f64 {
+	$if M is Something {
+		return 0
+	} $else {
+		panic('${typeof(M.typ).name} is not supported')
+		return 1
+	}
+	return 1
+}
+
+fn test_generic_method_with_multi_types() {
+	mut app := App<Some>{
+		f: Some{
+			i: 10
+		}
+	}
+	assert app.next(1) == 0
+}