:: a typeCtrl KGHC 9.10.3 · lts/ghc-9.10.x · 248f8f0 · 2026-10-05
Moduleghc-9.10.3GHC2021
Module for detecting if recompilation is required
Top level function to check if the version of an old interface file is equivalent to the current source file the user asked us to compile. If the same, we can avoid recompilation.
We return on the outside whether the interface file is up to date, providing evidence that is with a ModIface. In the case that it isn't, we may also return a found or provided ModIface. Why we don't always return the old one, if it exists, is unclear to me, except that I tried it and some tests failed (see #18205).
UpToDateeverything is up to date, recompilation is not required
NeedsRecompile !CompileReasonNeed to compile the module
Eq RecompileRequiredDefined in ghc-9.10.3 · GHC.Iface.RecompSemigroup RecompileRequiredDefined in ghc-9.10.3 · GHC.Iface.RecompMonoid RecompileRequiredDefined in ghc-9.10.3 · GHC.Iface.RecompOutputable RecompileRequiredDefined in ghc-9.10.3 · GHC.Iface.RecompUpToDateItem aThe item contained is validated to be up to date
OutOfDateItem !CompileReason (Maybe a)The item is are absent altogether or out of date, for the reason given.
Functor MaybeValidatedDefined in ghc-9.10.3 · GHC.Iface.RecompOutputable a => Outputable (MaybeValidated a)Defined in ghc-9.10.3 · GHC.Iface.RecompUnitDepRemoved UnitIdModulePackageChanged FastStringSourceFileChangedThisUnitIdChangedImpurePluginPluginsChangedPluginFingerprintChangedModuleInstChangedHieMissingHieOutdatedSigsMergeChangedModuleChanged ModuleNameModuleRemoved (UnitId, ModuleName)ModuleAdded (UnitId, ModuleName)ModuleChangedRaw ModuleNameModuleChangedIface ModuleNameFileChanged FilePathCustomReason StringFlagsChangedOptimFlagsChangedHpcFlagsChangedMissingBytecodeMissingObjectFileMissingDynObjectFileMissingDynHiFileMismatchedDynHiFileObjectsChangedLibraryChangedTHWithJSEq RecompReasonDefined in ghc-9.10.3 · GHC.Iface.RecompOutputable RecompReasonDefined in ghc-9.10.3 · GHC.Iface.RecompMustCompileThe .hs file has been touched, or the .o/.hi file does not exist
RecompBecause !RecompReasonThe .o/.hi files are up to date, but something else has changed to force recompilation; the String says what (one-line summary)
Eq CompileReasonDefined in ghc-9.10.3 · GHC.Iface.RecompOutputable CompileReasonDefined in ghc-9.10.3 · GHC.Iface.RecompAdd fingerprints for top-level declarations to a ModIface.
See Note [Fingerprinting IfaceDecls]