Binary operator checking

[kaleidawave]

Current the functions to doing binary operations don't check the types of either side. First a bit of background:

There are two functions for binary operators, they are split between

• Mathematical and bitwise operations. Both sides have to be checked as there is no short circuiting behavior
• Logical operators. These can have logical operators (and in the future the RHS can be narrowed for && operations)

in and instanceof operators are handled specially on Environment

There is a also a current option strict_casts (it should probably be renamed to no_implicit_casts) in TypeCheckOptions. When this is true should not allow operations like "hi" + 2.

These two functions are currently set up to return a Result. However both the logic for checking the sides and the diagnostic has not been implemented. For example

ezno/checker/src/behavior/operations.rs

Lines 76 to 84 in 5021262

	pub fn evaluate_mathematical_operation(
	lhs: TypeId,
	operator: MathematicalAndBitwise,
	rhs: TypeId,
	types: &mut TypeStore,
	strict_casts: bool,
	) -> Result<TypeId, ()> {
	fn attempt_constant_math_operator(
	lhs: TypeId,

There are several things to carefully consider here

• Still want to enable Symbol.toPrimative behaviour with hints and such (that will require these functions to have all the context to be able to do a call_type
  • This should disallow Object.toPrimative fall through as this result are not useful