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:stepover ---> :steplocal, :stepmodule
[ghc-hetmet.git]
/
compiler
/
typecheck
/
TcClassDcl.lhs
diff --git
a/compiler/typecheck/TcClassDcl.lhs
b/compiler/typecheck/TcClassDcl.lhs
index
c545dc7
..
67f2945
100644
(file)
--- a/
compiler/typecheck/TcClassDcl.lhs
+++ b/
compiler/typecheck/TcClassDcl.lhs
@@
-425,7
+425,7
@@
mkMethId origin clas sel_id inst_tys
rho_ty = ASSERT( length tyvars == length inst_tys )
substTyWith tyvars inst_tys rho
(preds,tau) = tcSplitPhiTy rho_ty
rho_ty = ASSERT( length tyvars == length inst_tys )
substTyWith tyvars inst_tys rho
(preds,tau) = tcSplitPhiTy rho_ty
- first_pred = head preds
+ first_pred = ASSERT( not (null preds)) head preds
in
-- The first predicate should be of form (C a b)
-- where C is the class in question
in
-- The first predicate should be of form (C a b)
-- where C is the class in question
@@
-528,7
+528,7
@@
mkDefMethRhs origin clas inst_tys sel_id loc GenDefMeth
-- case we require that the instance decl is for a single-parameter
-- type class with type variable arguments:
-- instance (...) => C (T a b)
-- case we require that the instance decl is for a single-parameter
-- type class with type variable arguments:
-- instance (...) => C (T a b)
- clas_tyvar = head (classTyVars clas)
+ clas_tyvar = ASSERT (not (null (classTyVars clas))) head (classTyVars clas)
Just tycon = maybe_tycon
maybe_tycon = case inst_tys of
[ty] -> case tcSplitTyConApp_maybe ty of
Just tycon = maybe_tycon
maybe_tycon = case inst_tys of
[ty] -> case tcSplitTyConApp_maybe ty of