genType.import of nested types causes name conflicts in TypeScript 3.7.2

[wokalski]

[@genType.import ("./MyMath", "num")]
type num;

Generates:

import {num as num} from './MyMath';

// tslint:disable-next-line:interface-over-type-literal
export type num = num;

When you compile it with tsc you get:

Import declaration conflicts with local declaration of 't'.

[cristianoc]

@wokalski why regression vs just an issue?

If you rename t in type t = Js.Dict.t(tsunknown); you don't get issues right? Making sure that's the issue.

[cristianoc]

@wokalski

Btw notice:

[@genType.import "something"]
type t = some_type_definition;

is not a useful pattern.
If the type is imported, then it's not checked against the local definition.

[cristianoc]

I guess what we're looking at there is a feature request, where the above pattern is checked: there's the JS type definition, there's the Reason type definition, and one would like to check that they match.

And I guess match means something like: if the reason type rt maps to js type toJS(rt), then any value of type jstype defined in the JS file is also of type toJS(rt).

[wokalski]

Right @cristianoc. I figured it's better to use external and %identity in this case.

[wokalski]

I'm closing this one. Seems like an interesting feature @cristianoc but it feels like an error is a desirable result now. Maybe it should even fail during genType execution!

[wokalski]

Reopening:

[@genType.import ("./StyleSheet", "AnyStyleProp")]
type t;

compiles to:

/* TypeScript file generated by genType. */
/* eslint-disable import/first */


import {AnyStyleProp as t} from './StyleSheet';

// tslint:disable-next-line:interface-over-type-literal
export type t = t;

which causes the same error.

[cristianoc]

@wokalski thanks it appears I have zero examples of that pattern, and needs to be fixed.
Thanks for spotting it!

[cristianoc]

@wokalski I have added an example here: #303.

I think that's what you want.
While the tuple argument of @genType.import is used to access classes inside the module.

I strongly suspect this is not exactly clear from the documentation.

[cristianoc]

Maybe in the case of interfaces one does need that pattern?

[cristianoc]

Here's a very simple problematic example:

[@genType.import ("./MyMath", "num")]
type num;

gives

import {num as num} from './MyMath';

// tslint:disable-next-line:interface-over-type-literal
export type num = num;

[wokalski]

Yes @cristianoc, exactly. Let me put this example in the issue description so that it's clear in the future what it's about.

[cristianoc]

@wokalski I have added a few more examples here: #303.
They all type check for me. Including the "problematic" one above.

[cristianoc]

Maybe it's about choosing different example, or maybe it's about TS version and/or config.

[wokalski]

hmm, it's probably the version! I just upgraded 🤦‍♀
Version 3.7.2

[cristianoc]

@wokalski how did it go after version upgrade?

[wokalski]

I had to downgrade and I think it builds correctly now.

[cristianoc]

Closing optimistically.

[wokalski]

I mean that the code generated by genType is incompatible with new versions of typescript! I think this requires a re-open 😄

[cristianoc]

I can confirm repro on TS 3.7.2.

[cristianoc]

@wokalski fixed here: #304

[wokalski]

Great, thanks!