Details
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Task
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Resolution: Unresolved
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Major - P3
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Query Optimization
Description
When you call a template function with the wrong arguments, the default error message points to the implementation of the template, and buries the true problem in a list of "required from here" / "included from here" notes.
In C++20 we can use concepts and 'requires' clauses to improve these error messages. For example, if we add this clause:
template <typename T, typename... Args>
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requires(std::constructible_from<T, Args...>)
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static PolyValue make(Args&&... args) {
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return PolyValue{ControlBlockVTable<T, Ts...>::make(std::forward<Args>(args)...)};
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}
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then a misuse like ABT::make<Variable>(5) would be caught at the call site, instead of in polyvalue.h.
Another good candidate is algebra::transport. Specifying its requirements is probably harder because its interface has many different options. But that complex interface is also why improving its error messages would be so useful.
Attachments
Issue Links
- related to
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SERVER-76921 toolchain v4 clang-format unaware of C++20 `requires` clauses
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- Closed
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