A comparison operator, < <= > >=
op is one of: EXP.lessThan, EXP.lessOrEqual, EXP.greaterThan, EXP.greaterOrEqual
https://dlang.org/spec/expression.html#relation_expressions
The types for a binary expression are incompatible. Print error message.
Mark the operands as will never be dereferenced, which is useful info for @safe checks. Do before semantic() on operands rewrites them.
See Implementation
A comparison operator, < <= > >=
op is one of: EXP.lessThan, EXP.lessOrEqual, EXP.greaterThan, EXP.greaterOrEqual
https://dlang.org/spec/expression.html#relation_expressions