Do not generate warnings for compiler-generated code

Fixes Trac #1313

diff --git a/compiler/typecheck/TcRnDriver.lhs b/compiler/typecheck/TcRnDriver.lhs
index 07a48ae..05777df 100644 (file)
--- a/compiler/typecheck/TcRnDriver.lhs
+++ b/compiler/typecheck/TcRnDriver.lhs
@@ -688,12 +688,17 @@ tcTopSrcDecls boot_details
                -- We also typecheck any extra binds that came out 
                -- of the "deriving" process (deriv_binds)
         traceTc (text "Tc5") ;
-       (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
+       (tc_val_binds,   tcl_env) <- tcTopBinds val_binds ;
        setLclTypeEnv tcl_env   $ do {
 
+               -- Now GHC-generated derived bindings and generics
+               -- Do not generate warnings from compiler-generated code
+       (tc_deriv_binds, tcl_env) <- discardWarnings $ setOptM Opt_GlasgowExts $ 
+                                    tcTopBinds deriv_binds ;
+
                -- Second pass over class and instance declarations, 
         traceTc (text "Tc6") ;
-       (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
+       (inst_binds, tcl_env)     <- setLclTypeEnv tcl_env $ tcInstDecls2 tycl_decls inst_infos ;
        showLIE (text "after instDecls2") ;
 
                -- Foreign exports
@@ -708,6 +713,7 @@ tcTopSrcDecls boot_details
         traceTc (text "Tc7a") ;
        tcg_env <- getGblEnv ;
        let { all_binds = tc_val_binds   `unionBags`
+                         tc_deriv_binds `unionBags`
                          inst_binds     `unionBags`
                          foe_binds  ;