Add roles declarations to allow safe coercions

src/React/Basic.purs

@@ -139,7 +139,9 @@ foreign import createComponent
 -- |   identify the component. It receives the `ComponentSpec` as a prop and knows
 -- |   how to defer behavior to it. It requires very specific props and is not useful by
 -- |   itself from JavaScript. For JavaScript interop, see `toReactComponent`.__
-data Component props
+foreign import data Component :: Type -> Type
+
+type role Component representational
 
 -- | `Self` represents the component instance at a particular point in time.
 -- |
@@ -347,14 +349,20 @@ foreign import displayNameFromSelf
 -- | __*See also:* `element`, `toReactComponent`__
 foreign import data ReactComponent :: Type -> Type
 
+type role ReactComponent representational
+
 -- | An opaque representation of a React component's instance (`this` in the JavaScript
 -- | React paradigm). It exists as an escape hatch to unsafe behavior. Use it with
 -- | caution.
 foreign import data ReactComponentInstance :: Type -> Type -> Type
 
+type role ReactComponentInstance representational representational
+
 -- | A React Ref, as created by `React.createRef`
 foreign import data Ref :: Type -> Type
 
+type role Ref representational
+
 -- | Convert a React-Basic `ComponentSpec` to a JavaScript-friendly React component.
 -- | This function should only be used for JS interop and not normal React-Basic usage.
 -- |
@@ -374,6 +382,8 @@ foreign import toReactComponent
 
 foreign import data ReactContext :: Type -> Type
 
+type role ReactContext representational
+
 -- | Create a `ReactContext` given a default value. Use `provider` and `consumer`
 -- | to provide and consume context values. Alternatively, use `contextProvider`
 -- | and `contextConsumer` directly if a `ReactComponent` is required for interop.

src/React/Basic/Events.purs

@@ -17,7 +17,7 @@ import Data.Symbol (class IsSymbol, SProxy(SProxy))
 import Effect (Effect)
 import Effect.Uncurried (EffectFn1, mkEffectFn1)
 import Prim.Row as Row
-import Prim.RowList (kind RowList, class RowToList, Cons, Nil)
+import Prim.RowList (class RowToList, RowList, Cons, Nil)
 import Record (delete, get, insert)
 import Type.Data.RowList (RLProxy(..))
 
@@ -77,7 +77,7 @@ handler_ = mkEffectFn1 <<< const
 syntheticEvent :: EventFn SyntheticEvent SyntheticEvent
 syntheticEvent = identity
 
-class Merge (rl :: RowList) fns a r | rl -> fns, rl a -> r where
+class Merge (rl :: RowList Type) fns a r | rl -> fns, rl a -> r where
   mergeImpl :: RLProxy rl -> Record fns -> EventFn a (Record r)
 
 instance mergeNil :: Merge Nil () a () where