Remove Linear Implicit Parameters, and all their works

[ghc-hetmet.git] / compiler / typecheck / TcExpr.lhs

diff --git a/compiler/typecheck/TcExpr.lhs b/compiler/typecheck/TcExpr.lhs
index e6ab82b..d9e25c3 100644 (file)
--- a/compiler/typecheck/TcExpr.lhs
+++ b/compiler/typecheck/TcExpr.lhs
@@ -45,7 +45,7 @@ import TcType         ( TcType, TcSigmaType, TcRhoType, TvSubst,
                          mkTyVarTys, mkFunTys, 
                          tcMultiSplitSigmaTy, tcSplitFunTysN,
                          tcSplitTyConApp_maybe, 
-                         isSigmaTy, mkFunTy, mkTyConApp, isLinearPred,
+                         isSigmaTy, mkFunTy, mkTyConApp, 
                          exactTyVarsOfType, exactTyVarsOfTypes, 
                          zipTopTvSubst, zipOpenTvSubst, substTys, substTyVar
                        )
@@ -796,19 +796,9 @@ instFun orig fun subst tv_theta_prs
        = do { co_fn <- instCall orig tys theta
             ; go False (HsWrap co_fn fun) prs }
 
-       --      Hack Alert (want_method_inst)!
        -- See Note [No method sharing]
-       -- If   f :: (%x :: T) => Int -> Int
-       -- Then if we have two separate calls, (f 3, f 4), we cannot
-       -- make a method constraint that then gets shared, thus:
-       --      let m = f %x in (m 3, m 4)
-       -- because that loses the linearity of the constraint.
-       -- The simplest thing to do is never to construct a method constraint
-       -- in the first place that has a linear implicit parameter in it.
-    want_method_inst theta =  not (null theta)                 -- Overloaded
-                          && not (any isLinearPred theta)      -- Not linear
+    want_method_inst theta =  not (null theta) -- Overloaded
                           && not opt_NoMethodSharing
-               -- See Note [No method sharing] below
 \end{code}
 
 Note [Multiple instantiation]