Is it possible to implement multiple inheritance in a programming language that does not use a method resolution order (MRO) algorithm?

Multiple inheritance without a method resolution order (MRO) is possible, but it is extremely problematic and inefficient. MRO is needed to determine the order of method calls in case of name conflicts in the class hierarchy. Without MRO, the system cannot unambiguously decide which method to invoke if it is defined in multiple parent classes.

For example, in languages without MRO (or with a simple order, like in C++) there can be a "diamond problem" — ambiguity when inheriting from two classes that share a common ancestor. Without clear rules for resolving methods, this can lead to errors or code duplication.

Thus, multiple inheritance without MRO is technically possible, but it requires manual conflict resolution, which complicates maintenance and increases the risk of errors. In modern languages with multiple inheritance (e.g., Python), MRO is implemented precisely to solve these issues.