Type-based lookup in sub-expressions (Was: Can't use color name literals in struct property definitions)

[jturcotte]

struct S := {
    c: color,
}
Demo := Window {
    // OK
    property<color> c: red;
    // OK
    property<S> s1: {c: Colors.rgb(255,0,0)};
    // error: Unknown unqualified identifier 'red'
    property<S> s2: {c: red};
}

https://sixtyfps.io/releases/0.1.6/editor/?snippet=struct+S+%3A%3D+%7B%0A++++c%3A+color%2C%0A%7D%0ADemo+%3A%3D+Window+%7B%0A++++%2F%2F+OK%0A++++property%3Ccolor%3E+c%3A+red%3B%0A++++%2F%2F+OK%0A++++property%3CS%3E+s1%3A+%7Bc%3A+Colors.rgb%28255%2C0%2C0%29%7D%3B%0A++++%2F%2F+error%3A+Unknown+unqualified+identifier+%27red%27%0A++++property%3CS%3E+s2%3A+%7Bc%3A+red%7D%3B%0A%7D%0A

[ogoffart]

Yes, right now we only do "type-specific" lookup (colors, enums) depending of the type of the property itself.
Ideally we should use type inference and see the actual type of the expression we try to analyse.
We need to fix lookup rules anyway: #273

In the mean time, you can use Colors.red everywhere.

[jturcotte]

Would it make sense to write Colors.xyz in the documentation instead to prevent this surprise? I actually didn't know that color literals were defined in the Colors namespace.

I'm stumbled on this but I just noticed that there was also this section in the doc: https://sixtyfps.io/releases/0.1.6/docs/rust/sixtyfps/docs/langref/index.html#colors

[ogoffart]

Probably we should suggest to use Colors.xyz or EnumName.xyz if xyz is not found and it is the value of some enum.

===> #4397