As a developer I'd like to use type aliases as values (esp. in JSX tags)

[mor-n4]

When implementing the first iteration of type aliases, it was a deliberate decision to disallow the use of type aliases as values, because they are types only and do not have a representation at runtime.

For example, all the following is currently disallowed by a dedicated validation:

function foo(p: constructor{?}) {}

class Cls {}

type A = Cls;

A; // error: A type alias may not be used as a value.
new A(); // error: A type alias may not be used as a value.
foo(A); // error: A type alias may not be used as a value.

However, it would be possible to allow a type alias being used as a value iff it resolves to a type that is also a value (in the above cases, for example). In that case, the transpiler would have to rewrite the reference to the type alias to a reference to the aliased / actual type (in the example above, rewrite references to A to refs to Cls).

Such a use of a type alias as value might be particularly useful in a JSX tag.

At the moment, this ticket is mainly intended to keep track of this topic. It is not yet clear if such a feature is worth the effort/complexity, so this has to be clarified before starting with this user story.

WARNING: supporting this is not trivial, because

• the transpiler would have to insert additional imports (if the aliased type is declared in a different module than the type alias),
• some invalid cases have to be considered (e.g. what if only the type alias is exported but not the aliased type; what if the aliased type is declared in a different project and no direct project dependency exists to that project?).

[mor-n4]

IMPORTANT: the above, merged PR does not resolve this ticket!
It only included some preparations, see PR description for details.