Simple vs Compound Requirements

Understanding C++ concept requirements and return types

This medium-difficulty C++ question tests your ability to distinguish between simple and compound

The question asks you to identify which concept syntax enforces not just that an operator exists, but that it returns a specific type. This matters in practice because a template might compile with an operation that has the wrong return type, leading to silent failures downstream. The fix involves choosing between different requirement forms: simple requirements (which only check well-formedness) and compound requirements (which can also constrain the result).

• Simple vs. compound requirements in C++20 concepts
• Type checking within concept definitions
• How requires clauses interact with operator signatures