Question

So Int32 does not have an == operator but this is valid code

bool y = 6 == 5;

This is because Int32 is part of the primitive set of types. It effectively compiles to CEQ in IL.

So given a Type (with reflection) how can it be determined that that type supports CEQ when it has no == operator?

Answer 1

The spec says (§7.10):

The predefined integer comparison operators are:

bool operator ==(int x, int y);
bool operator ==(uint x, uint y);
bool operator ==(long x, long y);
bool operator ==(ulong x, ulong y);

The predefined floating-point comparison operators are:

bool operator ==(float x, float y);
bool operator ==(double x, double y);

The predefined decimal comparison operators are:

bool operator ==(decimal x, decimal y);
bool operator !=(decimal x, decimal y);

The predefined boolean equality operators are:

bool operator ==(bool x, bool y);
bool operator !=(bool x, bool y);

Every enumeration type implicitly provides the following predefined
comparison operators:

bool operator ==(E x, E y);
bool operator !=(E x, E y);

Note that decimal.operator == is a normal method, not a built-in operator. I’m not sure why it’s listed there.