Template parameters duplicated if template is forward-declared

[cbiffle]

Documentation lists template parameters twice if a template is forward-declared.

Found at commit b3fc442

Example input

template <typename X>
struct Unit;

template <typename X>
struct Unit {
  T contents;
};

Output

Notes

It doesn't matter if the forward declaration appears before or after the definition. That is, this produces the same output:

template <typename X>
struct Unit {
  T contents;
};

template <typename X>
struct Unit;

[cbiffle]

It may be worth noting that, if the template parameters have different names at each site, they are accumulated in the order they appear. e.g.

template <typename X>
struct Unit;

template <typename T>
struct Unit {};

is documented as Unit<X, T>.