...a template is void. A lambda without parameter types is a template. When a template...

...Issue 10602 - Error should state why wrong template lambda doesn'…" fixing this issue:

- Fix...

https://issues.dlang.org/show_bug.cgi?id=20275

Basile-z <b2.temp@gmx.com...

...make both exist in the set is "template constraint", one works given certain static conditions...

...show_bug.cgi?id=15459 .

Bottom line: template instances that are instantiated from speculative contexts...

...8): Error: none of the overloads of template `std.algorithm.sorting.sort` are callable using...

See:
https://dlang.org/spec/expression.html#is-type

As template parameter types seem to be distinguishable by syntax in my eyes:
https://dlang...

Thanks.

Though, is there any case where it wouldn't be a valid type?

...not issue an error for the undefined template `isOutputRange`.  This is an issue with std...