diff options
| -rw-r--r-- | ghc/compiler/typecheck/TcExpr.lhs | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index aae7a24896..6c32a246d3 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -347,8 +347,12 @@ tcMonoExpr (CCall lbl args may_gc is_asm ignored_fake_result_ty) res_ty in -- Arguments - mapNF_Tc (\ _ -> newTyVarTy_OpenKind) [1..(length args)] `thenNF_Tc` \ arg_tys -> - tcMonoExprs args arg_tys `thenTc` \ (args', args_lie) -> + let n_args = length args + tv_idxs | n_args == 0 = [] + | otherwise = [1..n_args] + in + mapNF_Tc (\ _ -> newTyVarTy_OpenKind) tv_idxs `thenNF_Tc` \ arg_tys -> + tcMonoExprs args arg_tys `thenTc` \ (args', args_lie) -> -- The argument types can be unboxed or boxed; the result -- type must, however, be boxed since it's an argument to the IO |