Typedoc produces incorrect documentation for equivalent type aliases

[handerss-spotfire]

Typedoc produces incorrect types in documentation when two type aliases are equivalent.

Example

type Foo = string | number;
type Bar = string | number;

declare function bar(): Bar;
declare function foo(): Foo;

This source produces documentation where the return type of the function foo is Bar. I expected the return type to be Foo.

This issue is new in 0.20.

Here's a repo with a reproducible example and resulting docs:

https://github.com/handerss-tibco/typedoc-alias-issue

https://handerss-tibco.github.io/typedoc-alias-issue/modules.html#foo

[Gerrit0]

Thanks for the reproduction!

Unfortunately... this is unfixable in the generic case. Fixing this specific case isn't too bad (0.20.13), but we rely on the type checker for getting the type of symbols... and the type checker doesn't preserve this information. Types may have a single aliasSymbol, but which type gets this symbol is determined by which alias is documented first... and once we have the type, we can't get back to the original declaration without a ridiculous amount of hackery.