diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/main/DynFlags.hs | 3 | ||||
| -rw-r--r-- | compiler/typecheck/TcDeriv.hs | 3 |
2 files changed, 5 insertions, 1 deletions
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs index 5bd8cb819f..45a465bd9c 100644 --- a/compiler/main/DynFlags.hs +++ b/compiler/main/DynFlags.hs @@ -920,6 +920,7 @@ data WarningFlag = | Opt_WarnUnusedPackages -- Since 8.10 | Opt_WarnInferredSafeImports -- Since 8.10 | Opt_WarnMissingSafeHaskellMode -- Since 8.10 + | Opt_WarnDerivingDefaults deriving (Eq, Show, Enum) data Language = Haskell98 | Haskell2010 @@ -4026,6 +4027,7 @@ wWarningFlagsDeps = [ Opt_WarnDeferredOutOfScopeVariables, flagSpec "deprecations" Opt_WarnWarningsDeprecations, flagSpec "deprecated-flags" Opt_WarnDeprecatedFlags, + flagSpec "deriving-defaults" Opt_WarnDerivingDefaults, flagSpec "deriving-typeable" Opt_WarnDerivingTypeable, flagSpec "dodgy-exports" Opt_WarnDodgyExports, flagSpec "dodgy-foreign-imports" Opt_WarnDodgyForeignImports, @@ -4824,6 +4826,7 @@ standardWarnings -- see Note [Documenting warning flags] Opt_WarnPartialTypeSignatures, Opt_WarnUnrecognisedPragmas, Opt_WarnDuplicateExports, + Opt_WarnDerivingDefaults, Opt_WarnOverflowedLiterals, Opt_WarnEmptyEnumerations, Opt_WarnMissingFields, diff --git a/compiler/typecheck/TcDeriv.hs b/compiler/typecheck/TcDeriv.hs index 0b78b8e2ed..d2b32e7d7d 100644 --- a/compiler/typecheck/TcDeriv.hs +++ b/compiler/typecheck/TcDeriv.hs @@ -1756,7 +1756,8 @@ mkNewTypeEqn -- DeriveAnyClass, but emitting a warning about the choice. -- See Note [Deriving strategies] when (newtype_deriving && deriveAnyClass) $ - lift $ addWarnTc NoReason $ sep + lift $ whenWOptM Opt_WarnDerivingDefaults $ + addWarnTc (Reason Opt_WarnDerivingDefaults) $ sep [ text "Both DeriveAnyClass and" <+> text "GeneralizedNewtypeDeriving are enabled" , text "Defaulting to the DeriveAnyClass strategy" |