missing_concrete_instance.m:014: Error: this abstract instance declaration for
missing_concrete_instance.m:014:   `missing_concrete_instance.foo(int)' has no
missing_concrete_instance.m:014:   corresponding concrete instance declaration
missing_concrete_instance.m:014:   in the implementation section.
missing_concrete_instance.m:018: Error: this abstract instance declaration for
missing_concrete_instance.m:018:   `missing_concrete_instance.foo(float)' has
missing_concrete_instance.m:018:   no corresponding concrete instance
missing_concrete_instance.m:018:   declaration in the implementation section.