Item 4: Know How to View Deduced Types

In additional to IDE support, you may use compiler diagonostics (e.g., use declared but undefined templates).

// Declared but undefined
template<typename T>
class TypeDisplayer;

// Compiler will report an error with x's type
TypeDisplayer<decltype(x)> xType;

Note that not all sources of type information are reliable.

• std::type_info::name is not reliable (the standard requires it to be unreliable)
• Sometimes IDE-reported type info is not reliable, too

If you don’t mind runtime costs, Boost.TypeIndex is a nice choice.