diff options
| author | hallgren <hallgren@chalmers.se> | 2014-04-04 16:50:12 +0000 |
|---|---|---|
| committer | hallgren <hallgren@chalmers.se> | 2014-04-04 16:50:12 +0000 |
| commit | d6d056034b2c75844c4c3b56fdcb5702fe2340a3 (patch) | |
| tree | 9823a0cbad35f27e38fee56c3483200e180d1d04 | |
| parent | ad5f7397ad75dfec25edbe9ad5b3d9916fa71fcd (diff) | |
TypeCheck.RConcrete: contravariance in table types
| -rw-r--r-- | src/compiler/GF/Compile/TypeCheck/RConcrete.hs | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/compiler/GF/Compile/TypeCheck/RConcrete.hs b/src/compiler/GF/Compile/TypeCheck/RConcrete.hs index 4bbd42271..16c6908da 100644 --- a/src/compiler/GF/Compile/TypeCheck/RConcrete.hs +++ b/src/compiler/GF/Compile/TypeCheck/RConcrete.hs @@ -683,7 +683,8 @@ checkIfEqLType gr g t u trm = do (Q (m,a), QC (n,b)) | a == b -> elem m (allExtendsPlus gr n) || elem n (allExtendsPlus gr m) - (Table a b, Table c d) -> alpha g a c && alpha g b d + -- contravariance + (Table a b, Table c d) -> alpha g c a && alpha g b d (Vr x, Vr y) -> x == y || elem (x,y) g || elem (y,x) g _ -> t == u --- the following should be one-way coercions only. AR 4/1/2001 |