If at compile time all modifiers are valid for all composables (https://kotlinlang.slack.com/archives/CJLTWPH7S/p1587486859370700?thread_ts=1587486512.370000&cid=CJLTWPH7S)... will there be any sort of compile-time checking for validity here? Lint rules, perhaps?

Possibly lint rules can help here, but there isn't really anything wrong with the example - you may want to have a left-aligned

Text

, horizontally aligned inside a

Card

for example - it's valid to express this, but it's just not always the accurate intention.

gravity

, like all modifiers, affects the element it is placed on, not children / the inside of that element

there isn't really anything wrong with the example

For this example, yes. But I get the sense that it's not universal: all modifiers will not make sense for all composables. For example, does the

aspectRatio

modifier work on

Text

? I am just having flashbacks to having to answer an endless series of support questions like "why isn't

android:orientation

working on my

RelativeLayout

?". 🤪

IIUC, aspectRatio does work. it applies to anything that operates in the layout system, which Text does. The only modifiers where this isn’t really true are ones that only really “do” anything if there parent asks them for something, which is what we call

ParentDataModifiers

currently (not sure if that’s a public type or not

Things like gravity are exposed only in scope of the layout containers where they're valid on children, and those receiver scopes are `@DslMarker`ed so the leaking of

this

is pretty minimal in practice