ghc-70.3 - Online in the Cloud

PROGRAM:

NAME

GHC - the Glasgow Haskell Compiler

SYNOPSIS

ghc [option|filename]...
ghci [option|filename]...

DESCRIPTION

This manual page documents briefly the ghc and ghci commands. Note that ghci is not yet
available on all architectures. Extensive documentation is available in various other
formats including DVI, PostScript and HTML; see below.

Each of GHC's command line options is classified as either static or dynamic. A static
flag may only be specified on the command line, whereas a dynamic flag may also be given
in an OPTIONS pragma in a source file or set from the GHCi command-line with :set.

As a rule of thumb, all the language options are dynamic, as are the warning options and
the debugging options.

The rest are static, with the notable exceptions of -v, -cpp, -fasm, -fvia-C, -fllvm, and
" -#include . The OPTIONS sections lists the status of each flag.

Common suffixes of file names for Haskell are:

.hs Haskell source code; preprocess, compile

.lhs literate Haskell source; unlit, preprocess, compile

.hi Interface file; contains information about exported symbols

.hc intermediate C files

.x_o way x object files; common ways are: p, u, s

.x_hi way x interface files

OPTIONS

Verbosity options
-v -vn -fprint-explicit-foralls -fprint-explicit-kinds -ferror-spans -Hsize
-Rghc-timing

Alternative modes of operation
--help,-? --interactive --make -e expr --show-iface -M --supported-extensions,
--supported-languages --show-options --info --version, -V --numeric-version
--print-libdir

Which phases to run
-E -C -S -c -x suffix

Redirecting output
-hcsuf suffix -hidir dir -hisuf suffix -o filename -odir dir -ohi filename -osuf
suffix -stubdir dir -dumpdir dir -outputdir dir

Keeping intermediate files
-keep-hc-file or
-keep-hc-files -keep-llvm-file or
-keep-llvm-files -keep-s-file or
-keep-s-files -keep-tmp-files

Temporary files
-tmpdir

Finding imports
-idir1:dir2:... -i

Interface file options
-ddump-hi -ddump-hi-diffs -ddump-minimal-imports --show-iface file

Recompilation checking
-fforce-recomp -fno-force-recomp

Interactive-mode options
-ignore-dot-ghci -ghci-script -fbreak-on-error -fno-break-on-error -fbreak-on-exception
-fno-break-on-exception -fghci-hist-size=n (default is 50) -fprint-evld-with-show
-fno-print-evld-with-show -fprint-bind-result -fno-print-bind-result
-fno-print-bind-contents -fno-implicit-import-qualified -interactive-print

Packages
-this-package-key P -package P -hide-all-packages -hide-package name -ignore-package
name -package-db file -clear-package-db -no-global-package-db -global-package-db
-no-user-package-db -user-package-db -no-auto-link-packages -trust P -distrust P
-distrust-all

Language options
-fcontext-stack=n -fglasgow-exts -fno-glasgow-exts -firrefutable-tuples
-fno-irrefutable-tuples -fpackage-trust -ftype-function-depth=n -XAllowAmbiguousTypes
-XNoAllowAmbiguousTypes -XArrows -XNoArrows -XAutoDeriveTypeable -XNoAutoDeriveTypeable
-XBangPatterns -XNoBangPatterns -XBinaryLiterals -XNoBinaryLiterals -XCApiFFI
-XNoCAPIFFI -XConstrainedClassMethods -XNoConstrainedClassMethods -XConstraintKinds
-XNoConstraintKinds -XCPP -XNoCPP -XDataKinds -XNoDataKinds -XDefaultSignatures
-XNoDefaultSignatures -XDeriveAnyClass -XNoDeriveAnyClass -XDeriveDataTypeable
-XNoDeriveDataTypeable -XDeriveFunctor -XNoDeriveFunctor -XDeriveFoldable
-XNoDeriveFoldable -XDeriveGeneric -XNoDeriveGeneric -XDeriveTraversable
-XNoDeriveTraversable -XDisambiguateRecordFields -XNoDisambiguateRecordFields
-XEmptyCase -XNoEmptyCase -XEmptyDataDecls -XNoEmptyDataDecls
-XExistentialQuantification -XNoExistentialQuantification -XExplicitForAll
-XNoExplicitForAll -XExplicitNamespaces -XNoExplicitNamespaces -XExtendedDefaultRules
-XNoExtendedDefaultRules -XFlexibleContexts -XNoFlexibleContexts -XFlexibleInstances
-XNoFlexibleInstances -XForeignFunctionInterface -XNoForeignFunctionInterface
-XFunctionalDependencies -XNoFunctionalDependencies -XGADTs -XNoGADTs -XGADTSyntax
-XNoGADTSyntax -XGeneralizedNewtypeDeriving -XNoGeneralizedNewtypeDeriving -XGenerics
-XNoGenerics -XImplicitParams -XNoImplicitParams -XNoImplicitPrelude -XImplicitPrelude
-XImpredicativeTypes -XNoImpredicativeTypes -XIncoherentInstances -XNoIncoherentInstances
-XInstanceSigs -XNoInstanceSigs -XInterruptibleFFI -XNoInterruptibleFFI -XKindSignatures
-XNoKindSignatures -XLambdaCase -XNoLambdaCase -XLiberalTypeSynonyms
-XNoLiberalTypeSynonyms -XMagicHash -XNoMagicHash -XMonadComprehensions
-XNoMonadComprehensions -XMonoLocalBinds -XNoMonoLocalBinds -XNoMonomorphismRestriction
-XMonomorphismRestriction -XMultiParamTypeClasses -XNoMultiParamTypeClasses -XMultiWayIf
-XNoMultiWayIf -XNamedFieldPuns -XNoNamedFieldPuns -XNamedWildCards -XNoNamedWildCards
-XNegativeLiterals -XNoNegativeLiterals -XNoNPlusKPatterns -XNPlusKPatterns
-XNullaryTypeClasses -XNoNullaryTypeClasses -XNumDecimals -XNoNumDecimals
-XOverlappingInstances -XNoOverlappingInstances -XOverloadedLists -XNoOverloadedLists
-XOverloadedStrings -XNoOverloadedStrings -XPackageImports -XNoPackageImports
-XParallelArrays -XNoParallelArrays -XParallelListComp -XNoParallelListComp
-XPartialTypeSignatures -XNoPartialTypeSignatures -XPatternGuards -XNoPatternGuards
-XPatternSynonyms -XNoPatternSynonyms -XPolyKinds -XNoPolyKinds -XPolymorphicComponents
-XNoPolymorphicComponents -XPostfixOperators -XNoPostfixOperators -XQuasiQuotes
-XNoQuasiQuotes -XRank2Types -XNoRank2Types -XRankNTypes -XNoRankNTypes
-XRebindableSyntax -XNoRebindableSyntax -XRecordWildCards -XNoRecordWildCards
-XRecursiveDo -XNoRecursiveDo -XRelaxedPolyRec -XNoRelaxedPolyRec -XRoleAnnotations
-XNoRoleAnnotations -XSafe -XScopedTypeVariables -XNoScopedTypeVariables
-XStandaloneDeriving -XNoStandaloneDeriving -XTemplateHaskell -XNoTemplateHaskell
-XNoTraditionalRecordSyntax -XTraditionalRecordSyntax -XTransformListComp
-XNoTransformListComp -XTrustworthy -XTupleSections -XNoTupleSections -XTypeFamilies
-XNoTypeFamilies -XTypeOperators -XNoTypeOperators -XTypeSynonymInstances
-XNoTypeSynonymInstances -XUnboxedTuples -XNoUnboxedTuples -XUndecidableInstances
-XNoUndecidableInstances -XUnicodeSyntax -XNoUnicodeSyntax -XUnliftedFFITypes
-XNoUnliftedFFITypes -XUnsafe -XViewPatterns -XNoViewPatterns

Warnings
-W -w -w -Wall -w -Werror -Wwarn -fdefer-type-errors -fno-defer-type-errors
-fdefer-typed-holes -fno-defer-typed-holes -fhelpful-errors -fno-helpful-errors
-fwarn-deprecated-flags -fno-warn-deprecated-flags -fwarn-duplicate-constraints
-fno-warn-duplicate-constraints -fwarn-duplicate-exports -fno-warn-duplicate-exports
-fwarn-hi-shadowing -fno-warn-hi-shadowing -fwarn-identities -fno-warn-identities
-fwarn-implicit-prelude -fno-warn-implicit-prelude -fwarn-incomplete-patterns
-fno-warn-incomplete-patterns -fwarn-incomplete-uni-patterns
-fno-warn-incomplete-uni-patterns -fwarn-incomplete-record-updates
-fno-warn-incomplete-record-updates -fwarn-lazy-unlifted-bindings
-fno-warn-lazy-unlifted-bindings -fwarn-missing-fields -fno-warn-missing-fields
-fwarn-missing-import-lists -fnowarn-missing-import-lists -fwarn-missing-methods
-fno-warn-missing-methods -fwarn-missing-signatures -fno-warn-missing-signatures
-fwarn-missing-exported-sigs -fno-warn-missing-exported-sigs -fwarn-missing-local-sigs
-fno-warn-missing-local-sigs -fwarn-monomorphism-restriction
-fno-warn-monomorphism-restriction -fwarn-name-shadowing -fno-warn-name-shadowing
-fwarn-orphans, -fwarn-auto-orphans -fno-warn-orphans, -fno-warn-auto-orphans
-fwarn-overlapping-patterns -fno-warn-overlapping-patterns -fwarn-tabs -fno-warn-tabs
-fwarn-type-defaults -fno-warn-type-defaults -fwarn-unrecognised-pragmas
-fno-warn-unrecognised-pragmas -fwarn-unticked-promoted-constructors
-fno-warn-unticked-promoted-constructors -fwarn-unused-binds -fno-warn-unused-binds
-fwarn-unused-imports -fno-warn-unused-imports -fwarn-unused-matches
-fno-warn-unused-matches -fwarn-unused-do-bind -fno-warn-unused-do-bind
-fwarn-wrong-do-bind -fno-warn-wrong-do-bind -fwarn-unsafe -fno-warn-unsafe -fwarn-safe
-fno-warn-safe -fwarn-trustworthy-safe -fno-warn-safe -fwarn-warnings-deprecations
-fno-warn-warnings-deprecations -fwarn-amp -fno-warn-amp -fwarn-typed-holes
-fno-warn-typed-holes -fwarn-partial-type-signatures -fno-warn-partial-type-signatures
-fwarn-deriving-typeable -fno-warn-deriving-typeable

Optimisation levels
-O0 -O -O or -O1 -O0 -O2 -O0 -Odph

Individual optimisations
-fcall-arity -fno-call-arity -fcase-merge -fno-case-merge -fcmm-elim-common-blocks
-fno-cmm-elim-common-blocks -fcmm-sink -fno-cmm-sink -fcpr-off -fcse -fno-cse
-fdicts-cheap -fno-dicts-cheap -fdicts-strict -fno-dicts-strict -fdmd-tx-dict-sel
-fno-dmd-tx-dict-sel -fdo-eta-reduction -fno-do-eta-reduction
-fdo-lambda-eta-expansion -fno-do-lambda-eta-expansion -feager-blackholing
-fenable-rewrite-rules -fno-enable-rewrite-rules -fexcess-precision -fno-excess-precision
-fexpose-all-unfoldings -fno-expose-all-unfoldings -ffloat-in -fno-float-in
-ffull-laziness -fno-full-laziness -ffun-to-thunk -fno-fun-to-thunk -fignore-asserts
-fno-ignore-asserts -fignore-interface-pragmas -fno-ignore-interface-pragmas
-flate-dmd-anal -fno-late-dmd-anal -fliberate-case -fliberate-case-threshold=n
-fno-liberate-case-threshold -floopification -fno-loopification
-fmax-inline-alloc-size=n
-fmax-inline-memcpy-insns=n

-fmax-inline-memset-insns=n
-fmax-relevant-binds=n -fno-max-relevant-bindings
-fmax-simplifier-iterations=n -fmax-worker-args=n -fno-opt-coercion -fno-pre-inlining
-fno-state-hack -fomit-interface-pragmas -fno-omit-interface-pragmas -fomit-yields
-fno-omit-yields -fpedantic-bottoms -fno-pedantic-bottoms -fregs-graph -fno-regs-graph
-fregs-iterative -fno-regs-iterative -fsimplifier-phases=n -fsimpl-tick-factor=n
-fspec-constr -fno-spec-constr -fspec-constr-count=n -fno-spec-constr-count
-fspec-constr-threshold=n -fno-spec-constr-threshold -fspecialise -fno-specialise
-fstatic-argument-transformation -fno-static-argument-transformation -fstrictness
-fno-strictness -fstrictness-before=n -funbox-small-strict-fields
-fno-unbox-small-strict-fields -funbox-strict-fields -fno-unbox-strict-fields
-funfolding-creation-threshold=n -funfolding-dict-discount=n -funfolding-fun-discount=n
-funfolding-keeness-factor=n -funfolding-use-threshold=n -fvectorisation-avoidance
-fno-vectorisation-avoidance -fvectorise -fno-vectorise

Profiling options
-prof -fprof-auto -fno-prof-auto -fprof-auto-top -fno-prof-auto -fprof-auto-exported
-fno-prof-auto -fprof-cafs -fno-prof-cafs -fno-prof-count-entries -fprof-count-entries
-ticky

Program coverage options
-fhpc -hpcdir dir

Haskell pre-processor options
-F

C pre-processor options
-cpp -Dsymbol=value -U -Usymbol -Idir

Code generation options
-fasm -fllvm -fno-code -fwrite-interface -fbyte-code -fobject-code

Linking options
-shared -staticlib -fPIC -dynamic -dynamic-too -dyno -dynosuf -dynload -framework
name -framework-path name -llib -Ldir -main-is --mk-dll -no-hs-main -rtsopts,
-rtsopts={none,some,all} -with-rtsopts=opts -no-link -split-objs -static -threaded
-debug -ticky -eventlog -fno-gen-manifest -fno-embed-manifest -fno-shared-implib
-dylib-install-name path -rdynamic

Plugin options
-fplugin=module -fplugin-opt=module:args

Replacing phases
-pgmL cmd -pgmP cmd -pgmc cmd -pgmlo cmd -pgmlc cmd -pgms cmd -pgma cmd -pgml cmd
-pgmdll cmd -pgmF cmd -pgmwindres cmd -pgmlibtool cmd -pgmreadelf cmd

Forcing options to particular phases
-optL option -optP option -optF option -optc option -optlo option -optlc option
-opta option -optl option -optdll option -optwindres option

Platform-specific options
-msse2

Compiler debugging options
-dcore-lint -ddump-to-file -ddump-asm -ddump-bcos -ddump-cmm -ddump-core-stats
-ddump-cse -ddump-deriv -ddump-ds -ddump-foreign -ddump-hpc -ddump-inlinings
-ddump-llvm -ddump-occur-anal -ddump-opt-cmm -ddump-parsed -ddump-prep -ddump-rn
-ddump-rule-firings -ddump-rule-rewrites -ddump-rules -ddump-vect -ddump-simpl
-ddump-simpl-iterations -ddump-spec -ddump-splices -ddump-stg -ddump-stranal
-ddump-strsigs -ddump-tc -dth-dec-file -ddump-types -ddump-worker-wrapper
-ddump-if-trace -ddump-tc-trace -ddump-vt-trace -ddump-rn-trace -ddump-rn-stats
-ddump-simpl-stats -dno-debug-output -dppr-debug -dppr-user-length -dppr-colsNNN
-dppr-case-as-let -dsuppress-all -dsuppress-uniques -dsuppress-idinfo
-dsuppress-module-prefixes -dsuppress-type-signatures -dsuppress-type-applications
-dsuppress-coercions -dsource-stats -dcmm-lint -dstg-lint -dstg-stats
-dverbose-core2core -dverbose-stg2stg -dshow-passes -dfaststring-stats -frule-check

Misc compiler options
-jN -fno-hi-version-check -fhistory-size -fno-ghci-history -fno-ghci-sandbox

VERBOSITY OPTIONS

-v verbose mode (equivalent to -v3)
[dynamic]

-vn set verbosity level
[dynamic]

-fprint-explicit-foralls
print explicit forall quantification in types
[dynamic]

-fprint-explicit-kinds
print explicit kind foralls and kind arguments in types
[dynamic]

-ferror-spans
output full span in error messages
[dynamic]

-Hsize Set the minimum heap size to size
[dynamic]

-Rghc-timing
Summarise timing stats for GHC (same as +RTS -tstderr)
[dynamic]

ALTERNATIVE MODES OF OPERATION

--help,-?
Disply help
[mode]

--interactive
Interactive mode - normally used by just running ghci; see for details.
[mode]

--make Build a multi-module Haskell program, automatically figuring out dependencies.
Likely to be much easier, and faster, than using make; see for details..
[mode]

-e expr
Evaluate expr; see for details.
[mode]

--show-iface
Display the contents of an interface file.
[mode]

-M Generate dependency information suitable for use in a Makefile; see for details.
[mode]

--supported-extensions, --supported-languages
display the supported language extensions
[mode]

--show-options
display the supported command line options
[mode]

--info display information about the compiler
[mode]

--version, -V
display GHC version
[mode]

--numeric-version
display GHC version (numeric only)
[mode]

--print-libdir
display GHC library directory
[mode]

WHICH PHASES TO RUN

-E Stop after preprocessing (.hspp file)
[mode]

-C Stop after generating C (.hc file)
[mode]

-S Stop after generating assembly (.s file)
[mode]

-c Stop after generating object (.o) file
[mode]

-x suffix
Override default behaviour for source files
[dynamic]

REDIRECTING OUTPUT

-hcsuf suffix
set the suffix to use for intermediate C files
[dynamic]

-hidir dir
set directory for interface files
[dynamic]

-hisuf suffix
set the suffix to use for interface files
[dynamic]

-o filename
set output filename
[dynamic]

-odir dir
set directory for object files
[dynamic]

-ohi filename
set the filename in which to put the interface
[dynamic]

-osuf suffix
set the output file suffix
[dynamic]

-stubdir dir
redirect FFI stub files
[dynamic]

-dumpdir dir
redirect dump files
[dynamic]

-outputdir dir
set output directory
[dynamic]

KEEPING INTERMEDIATE FILES

-keep-hc-file or
-keep-hc-files retain intermediate .hc files
[dynamic]

-keep-llvm-file or
-keep-llvm-files retain intermediate LLVM .ll files
[dynamic]

-keep-s-file or
-keep-s-files retain intermediate .s files
[dynamic]

-keep-tmp-files
retain all intermediate temporary files
[dynamic]

TEMPORARY FILES

-tmpdir
set the directory for temporary files
[dynamic]

FINDING IMPORTS

-idir1:dir2:...
add dir, dir2, etc. to import path
[dynamic/:set]

-i Empty the import directory list
[dynamic/:set]

INTERFACE FILE OPTIONS

-ddump-hi
Dump the new interface to stdout
[dynamic]

-ddump-hi-diffs
Show the differences vs. the old interface
[dynamic]

-ddump-minimal-imports
Dump a minimal set of imports
[dynamic]

--show-iface file
See .
[]

RECOMPILATION CHECKING

-fforce-recomp
Turn off recompilation checking. This is implied by any -ddump-X option when
compiling a single file (i.e. when using -c).
[dynamic]

INTERACTIVE-MODE OPTIONS

-ignore-dot-ghci
Disable reading of .ghci files
[dynamic]

-ghci-script
Read additional .ghci files
[dynamic]

-fbreak-on-error
Break on uncaught exceptions and errors
[dynamic]

-fbreak-on-exception
Break on any exception thrown
[dynamic]

-fghci-hist-size=n
Set the number of entries GHCi keeps for :history
[dynamic]

-fprint-evld-with-show
Enable usage of Show instances in :print
[dynamic]

-fprint-bind-result
Turn on printing of binding results in GHCi
[dynamic]

-fno-print-bind-contents
Turn off printing of binding contents in GHCi
[dynamic]

-fno-implicit-import-qualified
Turn off implicit qualified import of everything in GHCi
[dynamic]

-interactive-print
Select the function to use for printing evaluated expressions in GHCi
[dynamic]

PACKAGES

-this-package-key P
Compile to be part of package P
[dynamic]

-package P
Expose package P
[dynamic/:set]

-hide-all-packages
Hide all packages by default
[dynamic]

-hide-package name
Hide package P
[dynamic/:set]

-ignore-package name
Ignore package P
[dynamic/:set]

-package-db file
Add file to the package db stack.
[dynamic]

-clear-package-db
Clear the package db stack.
[dynamic]

-no-global-package-db
Remove the global package db from the stack.
[dynamic]

-global-package-db
Add the global package db to the stack.
[dynamic]

-no-user-package-db
Remove the user's package db from the stack.
[dynamic]

-user-package-db
Add the user's package db to the stack.
[dynamic]

-no-auto-link-packages
Don't automatically link in the base and rts packages.
[dynamic]

-trust P
Expose package P and set it to be trusted
[dynamic/:set]

-distrust P
Expose package P and set it to be distrusted
[dynamic/:set]

-distrust-all
Distrust all packages by default
[dynamic/:set]

LANGUAGE OPTIONS

-fcontext-stack=n
set the limit for type-class context reduction. Default is 100.
[dynamic]

-fglasgow-exts
Deprecated. Enable most language extensions; see for exactly which ones.
[dynamic]

-firrefutable-tuples
Make tuple pattern matching irrefutable
[dynamic]

-fpackage-trust
Enable Safe Haskell trusted package requirement for trustworthy modules.
[dynamic]

-ftype-function-depth=n
set the limit for type function reductions. Default is 200.
[dynamic]

-XAllowAmbiguousTypes
Allow the user to write ambiguous types, and the type inference engine to infer
them.
[dynamic]

-XArrows
Enable arrow notation extension
[dynamic]

-XAutoDeriveTypeable
As of GHC 7.10, this option is not needed, and should not be used. Automatically
derive Typeable instances for every datatype and type class declaration. Implies
-XDeriveDataTypeable.
[dynamic]

-XBangPatterns
Enable bang patterns.
[dynamic]

-XBinaryLiterals
Enable support for binary literals.
[dynamic]

-XCApiFFI
Enable the CAPI calling convention.
[dynamic]

-XConstrainedClassMethods
Enable constrained class methods.
[dynamic]

-XConstraintKinds
Enable a kind of constraints.
[dynamic]

-XCPP Enable the C preprocessor.
[dynamic]

-XDataKinds
Enable datatype promotion.
[dynamic]

-XDefaultSignatures
Enable default signatures.
[dynamic]

-XDeriveAnyClass
Enable deriving for any class.
[dynamic]

-XDeriveDataTypeable
Enable deriving for the Data class. Implied by -XAutoDeriveTypeable.
[dynamic]

-XDeriveFunctor
Enable deriving for the Functor class. Implied by -XDeriveTraversable.
[dynamic]

-XDeriveFoldable
Enable deriving for the Foldable class. Implied by -XDeriveTraversable.
[dynamic]

-XDeriveGeneric
Enable deriving for the Generic class.
[dynamic]

-XDeriveTraversable
Enable deriving for the Traversable class. Implies -XDeriveFunctor and
-XDeriveFoldable.
[dynamic]

-XDisambiguateRecordFields
Enable record field disambiguation. Implied by -XRecordWildCards.
[dynamic]

-XEmptyCase
Allow empty case alternatives.
[dynamic]

-XEmptyDataDecls
Enable empty data declarations.
[dynamic]

-XExistentialQuantification
Enable existential quantification.
[dynamic]

-XExplicitForAll
Enable explicit universal quantification. Implied by -XScopedTypeVariables,
-XLiberalTypeSynonyms, -XRankNTypes and -XExistentialQuantification.
[dynamic]

-XExplicitNamespaces
Enable using the keyword type to specify the namespace of entries in imports and
exports (). Implied by -XTypeOperators and -XTypeFamilies.
[dynamic]

-XExtendedDefaultRules
Use GHCi's extended default rules in a normal module.
[dynamic]

-XFlexibleContexts
Enable flexible contexts. Implied by -XImplicitParams.
[dynamic]

-XFlexibleInstances
Enable flexible instances. Implies -XTypeSynonymInstances. Implied by
-XImplicitParams.
[dynamic]

-XForeignFunctionInterface
Enable foreign function interface.
[dynamic]

-XFunctionalDependencies
Enable functional dependencies. Implies -XMultiParamTypeClasses.
[dynamic]

-XGADTs
Enable generalised algebraic data types. Implies -XGADTSyntax and -XMonoLocalBinds.
[dynamic]

-XGADTSyntax
Enable generalised algebraic data type syntax.
[dynamic]

-XGeneralizedNewtypeDeriving
Enable newtype deriving.
[dynamic]

-XGenerics
Deprecated, does nothing. No longer enables generic classes. See also GHC's support
for generic programming.
[dynamic]

-XImplicitParams
Enable Implicit Parameters. Implies -XFlexibleContexts and -XFlexibleInstances.
[dynamic]

-XNoImplicitPrelude
Don't implicitly import Prelude. Implied by -XRebindableSyntax.
[dynamic]

-XImpredicativeTypes
Enable impredicative types. Implies -XRankNTypes.
[dynamic]

-XIncoherentInstances
Enable incoherent instances. Implies -XOverlappingInstances.
[dynamic]

-XInstanceSigs
Enable instance signatures.
[dynamic]

-XInterruptibleFFI
Enable interruptible FFI.
[dynamic]

-XKindSignatures
Enable kind signatures. Implied by -XTypeFamilies and -XPolyKinds.
[dynamic]

-XLambdaCase
Enable lambda-case expressions.
[dynamic]

-XLiberalTypeSynonyms
Enable liberalised type synonyms.
[dynamic]

-XMagicHash
Allow "#" as a postfix modifier on identifiers.
[dynamic]

-XMonadComprehensions
Enable monad comprehensions.
[dynamic]

-XMonoLocalBinds
Enable do not generalise local bindings. Implied by -XTypeFamilies and -XGADTs.
[dynamic]

-XNoMonomorphismRestriction
Disable the monomorphism restriction.
[dynamic]

-XMultiParamTypeClasses
Enable multi parameter type classes. Implied by -XFunctionalDependencies.
[dynamic]

-XMultiWayIf
Enable multi-way if-expressions.
[dynamic]

-XNamedFieldPuns
Enable record puns.
[dynamic]

-XNamedWildCards
Enable named wildcards.
[dynamic]

-XNegativeLiterals
Enable support for negative literals.
[dynamic]

-XNoNPlusKPatterns
Disable support for n+k patterns.
[dynamic]

-XNullaryTypeClasses
Deprecated, does nothing. nullary (no parameter) type classes are now enabled using
-XMultiParamTypeClasses.
[dynamic]

-XNumDecimals
Enable support for 'fractional' integer literals.
[dynamic]

-XOverlappingInstances
Enable overlapping instances.
[dynamic]

-XOverloadedLists
Enable overloaded lists.
[dynamic]

-XOverloadedStrings
Enable overloaded string literals.
[dynamic]

-XPackageImports
Enable package-qualified imports.
[dynamic]

-XParallelArrays
Enable parallel arrays. Implies -XParallelListComp.
[dynamic]

-XParallelListComp
Enable parallel list comprehensions. Implied by -XParallelArrays.
[dynamic]

-XPartialTypeSignatures
Enable partial type signatures.
[dynamic]

-XPatternGuards
Enable pattern guards.
[dynamic]

-XPatternSynonyms
Enable pattern synonyms.
[dynamic]

-XPolyKinds
Enable kind polymorphism. Implies -XKindSignatures.
[dynamic]

-XPolymorphicComponents
Enable polymorphic components for data constructors.
[dynamic, synonym for -XRankNTypes]

-XPostfixOperators
Enable postfix operators.
[dynamic]

-XQuasiQuotes
Enable quasiquotation.
[dynamic]

-XRank2Types
Enable rank-2 types.
[dynamic, synonym for -XRankNTypes]

-XRankNTypes
Enable rank-N types. Implied by -XImpredicativeTypes.
[dynamic]

-XRebindableSyntax
Employ rebindable syntax. Implies -XNoImplicitPrelude.
[dynamic]

-XRecordWildCards
Enable record wildcards. Implies -XDisambiguateRecordFields.
[dynamic]

-XRecursiveDo
Enable recursive do (mdo) notation.
[dynamic]

-XRelaxedPolyRec
(deprecated) Relaxed checking for mutually-recursive polymorphic functions.
[dynamic]

-XRoleAnnotations
Enable role annotations.
[dynamic]

-XSafe Enable the Safe Haskell Safe mode.
[dynamic]

-XScopedTypeVariables
Enable lexically-scoped type variables.
[dynamic]

-XStandaloneDeriving
Enable standalone deriving.
[dynamic]

-XTemplateHaskell
Enable Template Haskell.
[dynamic]

-XNoTraditionalRecordSyntax
Disable support for traditional record syntax (as supported by Haskell 98) C {f =
x}
[dynamic]

-XTransformListComp
Enable generalised list comprehensions.
[dynamic]

-XTrustworthy
Enable the Safe Haskell Trustworthy mode.
[dynamic]

-XTupleSections
Enable tuple sections.
[dynamic]

-XTypeFamilies
Enable type families. Implies -XExplicitNamespaces, -XKindSignatures and
-XMonoLocalBinds.
[dynamic]

-XTypeOperators
Enable type operators. Implies -XExplicitNamespaces.
[dynamic]

-XTypeSynonymInstances
Enable type synonyms in instance heads. Implied by -XFlexibleInstances.
[dynamic]

-XUnboxedTuples
Enable unboxed tuples.
[dynamic]

-XUndecidableInstances
Enable undecidable instances.
[dynamic]

-XUnicodeSyntax
Enable unicode syntax.
[dynamic]

-XUnliftedFFITypes
Enable unlifted FFI types.
[dynamic]

-XUnsafe
Enable Safe Haskell Unsafe mode.
[dynamic]

-XViewPatterns
Enable view patterns.
[dynamic]

WARNINGS

-W enable normal warnings
[dynamic]

-w disable all warnings
[dynamic]

-Wall enable almost all warnings (details in )
[dynamic]

-Werror
make warnings fatal
[dynamic]

-Wwarn make warnings non-fatal
[dynamic]

-fdefer-type-errors
Turn type errors into warnings, deferring the error until runtime. Implies
-fdefer-typed-holes.
[dynamic]

-fdefer-typed-holes
Convert typed hole errors into warnings, deferring the error until runtime. Implied
by -fdefer-type-errors. See also -fwarn-typed-holes.
[dynamic]

-fhelpful-errors
Make suggestions for mis-spelled names.
[dynamic]

-fwarn-deprecated-flags
warn about uses of commandline flags that are deprecated
[dynamic]

-fwarn-duplicate-constraints
warn when a constraint appears duplicated in a type signature
[dynamic]

-fwarn-duplicate-exports
warn when an entity is exported multiple times
[dynamic]

-fwarn-hi-shadowing
warn when a .hi file in the current directory shadows a library
[dynamic]

-fwarn-identities
warn about uses of Prelude numeric conversions that are probably the identity (and
hence could be omitted)
[dynamic]

-fwarn-implicit-prelude
warn when the Prelude is implicitly imported
[dynamic]

-fwarn-incomplete-patterns
warn when a pattern match could fail
[dynamic]

-fwarn-incomplete-uni-patterns
warn when a pattern match in a lambda expression or pattern binding could fail
[dynamic]

-fwarn-incomplete-record-updates
warn when a record update could fail
[dynamic]

-fwarn-lazy-unlifted-bindings
(deprecated) warn when a pattern binding looks lazy but must be strict
[dynamic]

-fwarn-missing-fields
warn when fields of a record are uninitialised
[dynamic]

-fwarn-missing-import-lists
warn when an import declaration does not explicitly list all the names brought into
scope
[dynamic]

-fwarn-missing-methods
warn when class methods are undefined
[dynamic]

-fwarn-missing-signatures
warn about top-level functions without signatures
[dynamic]

-fwarn-missing-exported-sigs
warn about top-level functions without signatures, only if they are exported. takes
precedence over -fwarn-missing-signatures
[dynamic]

-fwarn-missing-local-sigs
warn about polymorphic local bindings without signatures
[dynamic]

-fwarn-monomorphism-restriction
warn when the Monomorphism Restriction is applied
[dynamic]

-fwarn-name-shadowing
warn when names are shadowed
[dynamic]

-fwarn-orphans, -fwarn-auto-orphans
warn when the module contains orphan instance declarations or rewrite rules
[dynamic]

-fwarn-overlapping-patterns
warn about overlapping patterns
[dynamic]

-fwarn-tabs
warn if there are tabs in the source file
[dynamic]

-fwarn-type-defaults
warn when defaulting happens
[dynamic]

-fwarn-unrecognised-pragmas
warn about uses of pragmas that GHC doesn't recognise
[dynamic]

-fwarn-unticked-promoted-constructors
warn if promoted constructors are not ticked
[dynamic]

-fwarn-unused-binds
warn about bindings that are unused
[dynamic]

-fwarn-unused-imports
warn about unnecessary imports
[dynamic]

-fwarn-unused-matches
warn about variables in patterns that aren't used
[dynamic]

-fwarn-unused-do-bind
warn about do bindings that appear to throw away values of types other than ()
[dynamic]

-fwarn-wrong-do-bind
warn about do bindings that appear to throw away monadic values that you should
have bound instead
[dynamic]

-fwarn-unsafe
warn if the module being compiled is regarded to be unsafe. Should be used to check
the safety status of modules when using safe inference. Works on all module types,
even those using explicit Safe Haskell modes (such as -XTrustworthy) and so can be
used to have the compiler check any assumptions made.
[dynamic]

-fwarn-safe
warn if the module being compiled is regarded to be safe. Should be used to check
the safety status of modules when using safe inference. Works on all module types,
even those using explicit Safe Haskell modes (such as -XTrustworthy) and so can be
used to have the compiler check any assumptions made.
[dynamic]

-fwarn-trustworthy-safe
warn if the module being compiled is marked as -XTrustworthy but it could instead
be marked as -XSafe, a more informative bound. Can be used to detect once a Safe
Haskell bound can be improved as dependencies are updated.
[dynamic]

-fwarn-warnings-deprecations
warn about uses of functions & types that have warnings or deprecated pragmas
[dynamic]

-fwarn-amp
(deprecated) warn on definitions conflicting with the Applicative-Monad Proposal
(AMP)
[dynamic]

-fwarn-typed-holes
Report warnings when typed hole errors are deferred until runtime. See
-fdefer-typed-holes.
[dynamic]

-fwarn-partial-type-signatures
warn about holes in partial type signatures when -XPartialTypesignatures is
enabled. Not applicable when -XPartialTypesignatures is not enabled, in which case
errors are generated for such holes. See .
[dynamic]

-fwarn-deriving-typeable
warn when encountering a request to derive an instance of class Typeable. As of GHC
7.10, such declarations are unnecessary and are ignored by the compiler because GHC
has a custom solver for discharging this type of constraint.
[dynamic]

OPTIMISATION LEVELS

-O0 Disable optimisations (default)
[dynamic]

-O or -O1
Enable level 1 optimisations
[dynamic]

-O2 Enable level 2 optimisations
[dynamic]

-Odph Enable level 2 optimisations, set -fmax-simplifier-iterations=20 and
-fsimplifier-phases=3.
[dynamic]

INDIVIDUAL OPTIMISATIONS

-fcall-arity
Enable call-arity optimisation. Implied by -O.
[dynamic]

-fcase-merge
Enable case-merging. Implied by -O.
[dynamic]

-fcmm-elim-common-blocks
Enable Cmm common block elimination. Implied by -O.
[dynamic]

-fcmm-sink
Enable Cmm sinking. Implied by -O.
[dynamic]

-fcpr-off
Switch off CPR analysis in the demand analyser.
[static]

-fcse Enable common sub-expression elimination. Implied by -O.
[dynamic]

-fdicts-cheap
Make dictionary-valued expressions seem cheap to the optimiser.
[dynamic]

-fdicts-strict
Make dictionaries strict
[dynamic]

-fdmd-tx-dict-sel

Use a special demand transformer for dictionary selectors. Always enabled by
default.
[dynamic]

-fdo-eta-reduction
Enable eta-reduction. Implied by -O.
[dynamic]

-fdo-lambda-eta-expansion
Enable lambda eta-expansion. Always enabled by default.
[dynamic]

-feager-blackholing
Turn on eager blackholing
[dynamic]

-fenable-rewrite-rules
Switch on all rewrite rules (including rules generated by automatic specialisation
of overloaded functions). Implied by -O.
[dynamic]

-fexcess-precision
Enable excess intermediate precision
[dynamic]

-fexpose-all-unfoldings
Expose all unfoldings, even for very large or recursive functions.
[dynamic]

-ffloat-in
Turn on the float-in transformation. Implied by -O.
[dynamic]

-ffull-laziness
Turn on full laziness (floating bindings outwards). Implied by -O.
[dynamic]

-ffun-to-thunk
Allow worker-wrapper to convert a function closure into a thunk if the function
does not use any of its arguments. Off by default.
[dynamic]

-fignore-asserts
Ignore assertions in the source. Implied by -O.
[dynamic]

-fignore-interface-pragmas
Ignore pragmas in interface files. Implied by -O0 only.
[dynamic]

-flate-dmd-anal
Run demand analysis again, at the end of the simplification pipeline
[dynamic]

-fliberate-case
Turn on the liberate-case transformation. Implied by -O2.
[dynamic]

-fliberate-case-threshold=n
Set the size threshold for the liberate-case transformation to n (default: 2000)
[dynamis]

-floopification
Turn saturated self-recursive tail-calls into local jumps in the generated
assembly. Implied by -O.
[dynamic]

-fmax-inline-alloc-size=n
Set the maximum size of inline array allocations to n bytes (default: 128). GHC
will allocate non-pinned arrays of statically known size in the current nursery
block if they're no bigger than n bytes, ignoring GC overheap. This value should be
quite a bit smaller than the block size (typically: 4096).
[dynamic]

-fmax-inline-memcpy-insns=n

Inline memcpy calls if they would generate no more than n pseudo instructions
(default: 32).
[dynamic]

-fmax-inline-memset-insns=n

Inline memset calls if they would generate no more than n pseudo instructions
(default: 32).
[dynamic]

-fmax-relevant-binds=n
Set the maximum number of bindings to display in type error messages (default 6).
[dynamic]

-fmax-simplifier-iterations=n
Set the max iterations for the simplifier (default 4).
[dynamic]

-fmax-worker-args=n
If a worker has that many arguments, none will be unpacked anymore (default: 10)
[dynamic]

-fno-opt-coercion
Turn off the coercion optimiser
[static]

-fno-pre-inlining
Turn off pre-inlining
[dynamic]

-fno-state-hack
Turn off the "state hack" whereby any lambda with a real-world state token as
argument is considered to be single-entry. Hence OK to inline things inside it.
[static]

-fomit-interface-pragmas
Don't generate interface pragmas. Implied by -O0 only.
[dynamic]

-fomit-yields
Omit heap checks when no allocation is being performed.
[dynamic]

-fpedantic-bottoms
Make GHC be more precise about its treatment of bottom (but see also
-fno-state-hack). In particular, GHC will not eta-expand through a case expression.
[dynamic]

-fregs-graph
Use the graph colouring register allocator for register allocation in the native
code generator. Implied by -O2.
[dynamic]

-fregs-iterative
Use the iterative coalescing graph colouring register allocator in the native code
generator.
[dynamic]

-fsimplifier-phases=n
Set the number of phases for the simplifier (default 2). Ignored with -O0.
[dynamic]

-fsimpl-tick-factor=n
Set the percentage factor for simplifier ticks (default 100)
[dynamic]

-fspec-constr
Turn on the SpecConstr transformation. Implied by -O2.
[dynamic]

-fspec-constr-count=n
Set to n (default: 3) the maximum number of specialisations that will be created
for any one function by the SpecConstr transformation
[dynamic]

-fspec-constr-threshold=n
Set the size threshold for the SpecConstr transformation to n (default: 2000)
[dynamic]

-fspecialise
Turn on specialisation of overloaded functions. Implied by -O.
[dynamic]

-fstatic-argument-transformation
Turn on the static argument transformation.
[dynamic]

-fstrictness
Turn on strictness analysis. Implied by -O.
[dynamic]

-fstrictness-before=n
Run an additional strictness analysis before simplifier phase n
[dynamic]

-funbox-small-strict-fields
Flatten strict constructor fields with a pointer-sized representation. Implied by
-O.
[dynamic]

-funbox-strict-fields
Flatten strict constructor fields
[dynamic]

-funfolding-creation-threshold=n
Tweak unfolding settings. Default: 750
[dynamic]

-funfolding-dict-discount=n
Tweak unfolding settings. Default: 30
[dynamic]

-funfolding-fun-discount=n
Tweak unfolding settings. Default: 60
[dynamic]

-funfolding-keeness-factor=n
Tweak unfolding settings. Default: 1.5
[dynamic]

-funfolding-use-threshold=n
Tweak unfolding settings. Default: 60
[dynamic]

-fvectorisation-avoidance
Enable vectorisation avoidance. Always enabled by default.
[dynamic]

-fvectorise
Enable vectorisation of nested data parallelism
[dynamic]

PROFILING OPTIONS

-prof Turn on profiling
[dynamic]

-fprof-auto
Auto-add SCCs to all bindings not marked INLINE
[dynamic]

-fprof-auto-top
Auto-add SCCs to all top-level bindings not marked INLINE
[dynamic]

-fprof-auto-exported
Auto-add SCCs to all exported bindings not marked INLINE
[dynamic]

-fprof-cafs
Auto-add SCCs to all CAFs
[dynamic]

-fno-prof-count-entries
Do not collect entry counts
[dynamic]

-ticky Turn on ticky-ticky profiling
[dynamic]

PROGRAM COVERAGE OPTIONS

-fhpc Turn on Haskell program coverage instrumentation
[dynamic]

-hpcdir dir
Directory to deposit .mix files during compilation (default is .hpc)
[dynamic]

HASKELL PRE-PROCESSOR OPTIONS

-F Enable the use of a pre-processor (set with -pgmF)
[dynamic]

C PRE-PROCESSOR OPTIONS

-cpp Run the C pre-processor on Haskell source files
[dynamic]

-Dsymbol=value
Define a symbol in the C pre-processor
[dynamic]

-Usymbol
Undefine a symbol in the C pre-processor
[dynamic]

-Idir Add dir to the directory search list for #include files
[dynamic]

CODE GENERATION OPTIONS

-fasm Use the native code generator
[dynamic]

-fllvm Compile using the LLVM code generator
[dynamic]

-fno-code
Omit code generation
[dynamic]

-fwrite-interface
Always write interface files
[dynamic]

-fbyte-code
Generate byte-code
[dynamic]

-fobject-code
Generate object code
[dynamic]

LINKING OPTIONS

-shared
Generate a shared library (as opposed to an executable)
[dynamic]

-staticlib
On Darwin/OS X/iOS only, generate a standalone static library (as opposed to an
executable). This is the usual way to compile for iOS.
[dynamic]

-fPIC Generate position-independent code (where available)
[dynamic]

-dynamic
Use dynamic Haskell libraries (if available)
[dynamic]

-dynamic-too
Build dynamic object files as well as static object files during compilation
[dynamic]

-dyno Set the output path for the dynamically linked objects
[dynamic]

-dynosuf
Set the output suffix for dynamic object files
[dynamic]

-dynload
Selects one of a number of modes for finding shared libraries at runtime.
[dynamic]

-framework name
On Darwin/OS X/iOS only, link in the framework name. This option corresponds to the
-framework option for Apple's Linker.
[dynamic]

-framework-path name
On Darwin/OS X/iOS only, add dir to the list of directories searched for
frameworks. This option corresponds to the -F option for Apple's Linker.
[dynamic]

-llib Link in library lib
[dynamic]

-Ldir Add dir to the list of directories searched for libraries
[dynamic]

-main-is
Set main module and function
[dynamic]

--mk-dll
DLL-creation mode (Windows only)
[dynamic]

-no-hs-main
Don't assume this program contains main
[dynamic]

-rtsopts, -rtsopts={none,some,all}
Control whether the RTS behaviour can be tweaked via command-line flags and the
GHCRTS environment variable. Using none means no RTS flags can be given; some means
only a minimum of safe options can be given (the default), and all (or no argument
at all) means that all RTS flags are permitted.
[dynamic]

-with-rtsopts=opts
Set the default RTS options to opts.
[dynamic]

-no-link
Omit linking
[dynamic]

-split-objs
Split objects (for libraries)
[dynamic]

-static
Use static Haskell libraries
[dynamic]

-threaded
Use the threaded runtime
[dynamic]

-debug Use the debugging runtime
[dynamic]

-ticky For linking, this simply implies -debug; see .
[dynamic]

-eventlog
Enable runtime event tracing
[dynamic]

-fno-gen-manifest
Do not generate a manifest file (Windows only)
[dynamic]

-fno-embed-manifest
Do not embed the manifest in the executable (Windows only)
[dynamic]

-fno-shared-implib
Don't generate an import library for a DLL (Windows only)
[dynamic]

-dylib-install-name path
Set the install name (via -install_name passed to Apple's linker), specifying the
full install path of the library file. Any libraries or executables that link with
it later will pick up that path as their runtime search location for it. (Darwin/OS
X only)
[dynamic]

-rdynamic
This instructs the linker to add all symbols, not only used ones, to the dynamic
symbol table. Currently Linux and Windows/MinGW32 only. This is equivalent to using
-optl -rdynamic on Linux, and -optl -export-all-symbols on Windows.
[dynamic]

PLUGIN OPTIONS

-fplugin=module
Load a plugin exported by a given module
[dynamic]

-fplugin-opt=module:args
Give arguments to a plugin module; module must be specified with -fplugin
[dynamic]

REPLACING PHASES

-pgmL cmd
Use cmd as the literate pre-processor
[dynamic]

-pgmP cmd
Use cmd as the C pre-processor (with -cpp only)
[dynamic]

-pgmc cmd
Use cmd as the C compiler
[dynamic]

-pgmlo cmd
Use cmd as the LLVM optimiser
[dynamic]

-pgmlc cmd
Use cmd as the LLVM compiler
[dynamic]

-pgms cmd
Use cmd as the splitter
[dynamic]

-pgma cmd
Use cmd as the assembler
[dynamic]

-pgml cmd
Use cmd as the linker
[dynamic]

-pgmdll cmd
Use cmd as the DLL generator
[dynamic]

-pgmF cmd
Use cmd as the pre-processor (with -F only)
[dynamic]

-pgmwindres cmd
Use cmd as the program for embedding manifests on Windows.
[dynamic]

-pgmlibtool cmd
Use cmd as the command for libtool (with -staticlib only).
[dynamic]

-pgmreadelf cmd
Use cmd as the command for readelf (part of Unix binutils)
[dynamic]

FORCING OPTIONS TO PARTICULAR PHASES

-optL option
pass option to the literate pre-processor
[dynamic]

-optP option
pass option to cpp (with -cpp only)
[dynamic]

-optF option
pass option to the custom pre-processor
[dynamic]

-optc option
pass option to the C compiler
[dynamic]

-optlo option
pass option to the LLVM optimiser
[dynamic]

-optlc option
pass option to the LLVM compiler
[dynamic]

-opta option
pass option to the assembler
[dynamic]

-optl option
pass option to the linker
[dynamic]

-optdll option
pass option to the DLL generator
[dynamic]

-optwindres option
pass option to windres.
[dynamic]

PLATFORM-SPECIFIC OPTIONS

-msse2 (x86 only) Use SSE2 for floating point
[dynamic]

COMPILER DEBUGGING OPTIONS

-dcore-lint
Turn on internal sanity checking
[dynamic]

-ddump-to-file
Dump to files instead of stdout
[dynamic]

-ddump-asm
Dump assembly
[dynamic]

-ddump-bcos
Dump interpreter byte code
[dynamic]

-ddump-cmm
Dump C-- output
[dynamic]

-ddump-core-stats
Print a one-line summary of the size of the Core program at the end of the
optimisation pipeline
[dynamic]

-ddump-cse
Dump CSE output
[dynamic]

-ddump-deriv
Dump deriving output
[dynamic]

-ddump-ds
Dump desugarer output
[dynamic]

-ddump-foreign
Dump foreign export stubs
[dynamic]

-ddump-hpc
Dump after instrumentation for program coverage
[dynamic]

-ddump-inlinings
Dump inlining info
[dynamic]

-ddump-llvm
Dump LLVM intermediate code
[dynamic]

-ddump-occur-anal
Dump occurrence analysis output
[dynamic]

-ddump-opt-cmm
Dump the results of C-- to C-- optimising passes
[dynamic]

-ddump-parsed
Dump parse tree
[dynamic]

-ddump-prep
Dump prepared core
[dynamic]

-ddump-rn
Dump renamer output
[dynamic]

-ddump-rule-firings
Dump rule firing info
[dynamic]

-ddump-rule-rewrites
Dump detailed rule firing info
[dynamic]

-ddump-rules
Dump rules
[dynamic]

-ddump-vect
Dump vectoriser input and output
[dynamic]

-ddump-simpl
Dump final simplifier output
[dynamic]

-ddump-simpl-iterations
Dump output from each simplifier iteration
[dynamic]

-ddump-spec
Dump specialiser output
[dynamic]

-ddump-splices
Dump TH spliced expressions, and what they evaluate to
[dynamic]

-ddump-stg
Dump final STG
[dynamic]

-ddump-stranal
Dump strictness analyser output
[dynamic]

-ddump-strsigs
Dump strictness signatures
[dynamic]

-ddump-tc
Dump typechecker output
[dynamic]

-dth-dec-file
Show evaluated TH declarations in a .th.hs file
[dynamic]

-ddump-types
Dump type signatures
[dynamic]

-ddump-worker-wrapper
Dump worker-wrapper output
[dynamic]

-ddump-if-trace
Trace interface files
[dynamic]

-ddump-tc-trace
Trace typechecker
[dynamic]

-ddump-vt-trace
Trace vectoriser
[dynamic]

-ddump-rn-trace
Trace renamer
[dynamic]

-ddump-rn-stats
Renamer stats
[dynamic]

-ddump-simpl-stats
Dump simplifier stats
[dynamic]

-dno-debug-output
Suppress unsolicited debugging output
[static]

-dppr-debug
Turn on debug printing (more verbose)
[static]

-dppr-user-length
Set the depth for printing expressions in error msgs
[dynamic]

-dppr-colsNNN
Set the width of debugging output. For example -dppr-cols200
[dynamic]

-dppr-case-as-let
Print single alternative case expressions as strict lets.
[dynamic]

-dsuppress-all
In core dumps, suppress everything (except for uniques) that is suppressible.
[dynamic]

-dsuppress-uniques
Suppress the printing of uniques in debug output (easier to use diff)
[dynamic]

-dsuppress-idinfo
Suppress extended information about identifiers where they are bound
[dynamic]

-dsuppress-module-prefixes
Suppress the printing of module qualification prefixes
[dynamic]

-dsuppress-type-signatures
Suppress type signatures
[dynamic]

-dsuppress-type-applications
Suppress type applications
[dynamic]

-dsuppress-coercions
Suppress the printing of coercions in Core dumps to make them shorter
[dynamic]

-dsource-stats
Dump haskell source stats
[dynamic]

-dcmm-lint
C-- pass sanity checking
[dynamic]

-dstg-lint
STG pass sanity checking
[dynamic]

-dstg-stats
Dump STG stats
[dynamic]

-dverbose-core2core
Show output from each core-to-core pass
[dynamic]

-dverbose-stg2stg
Show output from each STG-to-STG pass
[dynamic]

-dshow-passes
Print out each pass name as it happens
[dynamic]

-dfaststring-stats
Show statistics for fast string usage when finished
[dynamic]

-frule-check
Report sites with rules that could have fired but didn't. Takes a string argument.
[dynamic]

MISC COMPILER OPTIONS

-jN When compiling with --make, compile N modules in parallel.
[dynamic]

-fno-hi-version-check
Don't complain about .hi file mismatches
[dynamic]

-fhistory-size
Set simplification history size
[dynamic]

-fno-ghci-history
Do not use the load/store the GHCi command history from/to ghci_history.
[dynamic]

-fno-ghci-sandbox
Turn off the GHCi sandbox. Means computations are run in the main thread, rather
than a forked thread.
[dynamic]

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