init mg_inst_env when reading ext core

diff --git a/compiler/typecheck/TcRnDriver.lhs b/compiler/typecheck/TcRnDriver.lhs
index 8659401..e5f945c 100644 (file)
--- a/compiler/typecheck/TcRnDriver.lhs
+++ b/compiler/typecheck/TcRnDriver.lhs
@@ -314,6 +314,7 @@ tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
                                mg_types     = final_type_env,
                                mg_insts     = tcg_insts tcg_env,
                                mg_fam_insts = tcg_fam_insts tcg_env,
+                               mg_inst_env  = tcg_inst_env tcg_env,
                                mg_fam_inst_env = tcg_fam_inst_env tcg_env,
                                mg_rules     = [],
                                mg_binds     = core_binds,