diff options
| author | Simon Peyton Jones <simonpj@microsoft.com> | 2012-09-17 11:34:28 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2012-09-17 13:46:28 +0100 |
| commit | af7cc9953217d74e88d4d21512e957edd8e97ec9 (patch) | |
| tree | 35e6c6b82a87c65a6a28508a357c282deb4f8087 /compiler/deSugar | |
| parent | 510f4394b6574c930b71bd430ca2cb8d25022fac (diff) | |
| download | haskell-af7cc9953217d74e88d4d21512e957edd8e97ec9.tar.gz | |
Implement 'left' and 'right' coercions
This patch finally adds 'left' and 'right' coercions back into
GHC. Trac #7205 gives the details.
The main change is to add a new constructor to Coercion:
data Coercion
= ...
| NthCo Int Coercion -- OLD, still there
| LRCo LeftOrRight Coercion -- NEW
data LeftOrRight = CLeft | CRight
Plus:
* Similar change to TcCoercion
* Use LRCo when decomposing AppTys
* Coercion optimisation needs to handle left/right
The rest is just knock-on effects.
Diffstat (limited to 'compiler/deSugar')
| -rw-r--r-- | compiler/deSugar/DsBinds.lhs | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/compiler/deSugar/DsBinds.lhs b/compiler/deSugar/DsBinds.lhs index 803cdd886e..b418c8d592 100644 --- a/compiler/deSugar/DsBinds.lhs +++ b/compiler/deSugar/DsBinds.lhs @@ -834,6 +834,7 @@ ds_tc_coercion subst tc_co go (TcSymCo co) = mkSymCo (go co) go (TcTransCo co1 co2) = mkTransCo (go co1) (go co2) go (TcNthCo n co) = mkNthCo n (go co) + go (TcLRCo lr co) = mkLRCo lr (go co) go (TcInstCo co ty) = mkInstCo (go co) ty go (TcLetCo bs co) = ds_tc_coercion (ds_co_binds bs) co go (TcCastCo co1 co2) = mkCoCast (go co1) (go co2) |