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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2011-04-19 11:06:20 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2011-04-19 11:06:20 +0100 |
| commit | fdf8656855d26105ff36bdd24d41827b05037b91 (patch) | |
| tree | fbbaeb08132051cde17ec7c3020cb835b04b947e /compiler/deSugar/DsUtils.lhs | |
| parent | a52ff7619e8b7d74a9d933d922eeea49f580bca8 (diff) | |
| download | haskell-fdf8656855d26105ff36bdd24d41827b05037b91.tar.gz | |
This BIG PATCH contains most of the work for the New Coercion Representation
See the paper "Practical aspects of evidence based compilation in System FC"
* Coercion becomes a data type, distinct from Type
* Coercions become value-level things, rather than type-level things,
(although the value is zero bits wide, like the State token)
A consequence is that a coerion abstraction increases the arity by 1
(just like a dictionary abstraction)
* There is a new constructor in CoreExpr, namely Coercion, to inject
coercions into terms
Diffstat (limited to 'compiler/deSugar/DsUtils.lhs')
| -rw-r--r-- | compiler/deSugar/DsUtils.lhs | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/compiler/deSugar/DsUtils.lhs b/compiler/deSugar/DsUtils.lhs index 3a976878e3..8b5a26894f 100644 --- a/compiler/deSugar/DsUtils.lhs +++ b/compiler/deSugar/DsUtils.lhs @@ -53,7 +53,6 @@ import CoreUtils import MkCore import MkId import Id -import Var import Name import Literal import TyCon @@ -75,7 +74,6 @@ import StaticFlags \end{code} - %************************************************************************ %* * Rebindable syntax @@ -256,10 +254,9 @@ wrapBinds [] e = e wrapBinds ((new,old):prs) e = wrapBind new old (wrapBinds prs e) wrapBind :: Var -> Var -> CoreExpr -> CoreExpr -wrapBind new old body -- Can deal with term variables *or* type variables - | new==old = body - | isTyCoVar new = Let (mkTyBind new (mkTyVarTy old)) body - | otherwise = Let (NonRec new (Var old)) body +wrapBind new old body -- NB: this function must deal with term + | new==old = body -- variables, type variables or coercion variables + | otherwise = Let (NonRec new (varToCoreExpr old)) body seqVar :: Var -> CoreExpr -> CoreExpr seqVar var body = Case (Var var) var (exprType body) @@ -605,7 +602,7 @@ mkSelectorBinds pat val_expr return (bndr_var, rhs_expr) where error_expr = mkCoerce co (Var err_var) - co = mkUnsafeCoercion (exprType (Var err_var)) (idType bndr_var) + co = mkUnsafeCo (exprType (Var err_var)) (idType bndr_var) is_simple_lpat p = is_simple_pat (unLoc p) |