Prevent BLS Affine values from being coerced.

The same safeguard already existed for the Point type, but we also need it for Affine.
IntersectMBO · Jun 28, 2023 · 78e5d3f · 78e5d3f
1 parent cb31fe9
commit 78e5d3f
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/cardano-crypto-class/src/Cardano/Crypto/EllipticCurve/BLS12_381/Internal.hs b/cardano-crypto-class/src/Cardano/Crypto/EllipticCurve/BLS12_381/Internal.hs
@@ -232,6 +232,10 @@ type Point2 = Point Curve2
 
 newtype Affine curve = Affine (ForeignPtr Void)
 
+-- Making sure different 'Affine's are not 'Coercible', which would ruin the
+-- intended type safety:
+type role Affine nominal
+
 type Affine1 = Affine Curve1
 type Affine2 = Affine Curve2