1GHC(1)                     Glasgow Haskell Compiler                     GHC(1)
2
3
4

NAME

6       ghc - the Glasgow Haskell Compiler
7

SYNOPSIS

9          ghc [option|filename]
10          ghci [option|filename]
11

DESCRIPTION

13       This manual page documents briefly the ghc and ghci commands. Note that
14       ghci is not yet available on all architectures. Extensive documentation
15       is available in various other formats including PDF and HTML.
16
17       Each  of  GHC's  command line options is classified as either static or
18       dynamic. A static flag may only  be  specified  on  the  command  line,
19       whereas  a  dynamic  flag  may  also be given in an OPTIONS pragma in a
20       source file or set from the GHCi command-line with :set .
21
22       As a rule of thumb, all the language options are dynamic,  as  are  the
23       warning options and the debugging options.
24
25       The  rest  are  static, with the notable exceptions of -v, -cpp, -fasm,
26       -fvia-C, -fllvm, and -#include.  The OPTIONS sections lists the  status
27       of each flag.
28
29       Common suffixes of file names for Haskell are:
30
31       .hs    Haskell source code; preprocess, compile
32
33       .lhs   literate Haskell source; unlit, preprocess, compile
34
35       .hi    Interface file; contains information about exported symbols
36
37       .hc    intermediate C files
38
39       .⟨way⟩_o
40              object files for "way" ⟨way⟩; common ways are:
41
42              dyn    dynamically-linked
43
44              p      built with profiling
45
46       .⟨way⟩_hi
47              interface files for "way" ⟨way⟩; common ways are:
48

OPTIONS

50       Code generation
51              -dynamic-too  -fasm  -fllvm  -fbyte-code -fexternal-dynamic-refs
52              -fllvm -fasm -fno-code -fobject-code -fPIC -fPIE  -fwrite-inter‐
53              face
54
55       Debugging the compiler
56              -dcmm-lint     -dcore-lint     -ddump-asm    -ddump-asm-expanded
57              -ddump-asm-liveness    -ddump-asm-native     -ddump-asm-regalloc
58              -ddump-asm-regalloc-stages      -ddump-asm-stats     -ddump-bcos
59              -ddump-cfg-weights  -ddump-cmm   -ddump-cmm-caf   -ddump-cmm-cbe
60              -ddump-cmm-cfg         -ddump-cmm-cps        -ddump-cmm-from-stg
61              -ddump-cmm-info        -ddump-cmm-proc        -ddump-cmm-procmap
62              -ddump-cmm-raw  -ddump-cmm-sink  -ddump-cmm-sp  -ddump-cmm-split
63              -ddump-cmm-switch -ddump-cmm-verbose  -ddump-cmm-verbose-by-proc
64              -ddump-core-stats      -ddump-cse     -ddump-deriv     -ddump-ds
65              -ddump-ds-preopt    -ddump-ec-trace     -ddump-file-prefix=⟨str⟩
66              -ddump-foreign   -ddump-hpc   -ddump-if-trace   -ddump-inlinings
67              -ddump-json   -ddump-llvm    -ddump-mod-map    -ddump-occur-anal
68              -ddump-opt-cmm   -ddump-parsed   -ddump-parsed-ast   -ddump-prep
69              -ddump-rn    -ddump-rn-ast    -ddump-rn-stats    -ddump-rn-trace
70              -ddump-rtti       -ddump-rule-firings       -ddump-rule-rewrites
71              -ddump-rules        -ddump-simpl         -ddump-simpl-iterations
72              -ddump-simpl-stats    -ddump-spec    -ddump-splices   -ddump-stg
73              -ddump-stg-final    -ddump-stg-unarised    -ddump-str-signatures
74              -ddump-stranal     -ddump-tc    -ddump-tc-ast    -ddump-tc-trace
75              -ddump-ticked   -ddump-timings    -ddump-to-file    -ddump-types
76              -ddump-worker-wrapper   -dfaststring-stats   -dhex-word-literals
77              -dinitial-unique=⟨s⟩   -dinline-check=⟨str⟩    -dno-debug-output
78              -ddebug-output       -dno-typeable-binds       -dppr-case-as-let
79              -dppr-cols=⟨n⟩ -dppr-debug -dppr-user-length  -drule-check=⟨str⟩
80              -dshow-passes   -dstg-lint  -dsuppress-all  -dsuppress-coercions
81              -dsuppress-idinfo       -dsuppress-module-prefixes        -dsup‐
82              press-stg-free-vars    -dsuppress-ticks    -dsuppress-timestamps
83              -dsuppress-type-applications  -dsuppress-type-signatures  -dsup‐
84              press-unfoldings     -dsuppress-uniques     -dsuppress-var-kinds
85              -dth-dec-file -dunique-increment=⟨i⟩ -dverbose-core2core  -dver‐
86              bose-stg2stg       -falignment-sanitisation      -fcatch-bottoms
87              -fllvm-fill-undef-with-garbage -fproc-alignment -g -g⟨n⟩
88
89       C pre-processor
90              -cpp -D⟨symbol⟩[=⟨value⟩] -U⟨symbol⟩ -I⟨dir⟩ -U⟨symbol⟩
91
92       Finding imports
93              -i -i⟨dir⟩[:⟨dir⟩]*
94
95       Interactive mode
96              -fbreak-on-error    -fno-break-on-error     -fbreak-on-exception
97              -fno-break-on-exception  -fghci-hist-size=⟨n⟩  -fghci-leak-check
98              -fno-ghci-leak-check  -flocal-ghci-history  -fno-local-ghci-his‐
99              tory  -fno-it -fno-no-it -fprint-bind-result -fno-print-bind-re‐
100              sult -fprint-evld-with-show  -fshow-loaded-modules  -ghci-script
101              -ignore-dot-ghci -interactive-print ⟨name⟩
102
103       Interface files
104              --show-iface ⟨file⟩ -ddump-hi -ddump-hi-diffs -ddump-minimal-im‐
105              ports
106
107       Keeping intermediate files
108              -keep-hc-file  -keep-hc-files  -keep-hi-files  -no-keep-hi-files
109              -keep-hscpp-file        -keep-hscpp-files        -keep-llvm-file
110              -keep-llvm-files  -keep-o-files  -no-keep-o-files   -keep-s-file
111              -keep-s-files -keep-tmp-files
112
113       Language options
114              -fno-safe-haskell                       -fsort-by-size-hole-fits
115              -fno-sort-by-size-hole-fits      -fsort-by-subsumption-hole-fits
116              -fno-sort-by-subsumption-hole-fits       -Winferred-safe-imports
117              -Wno-inferred-safe-imports           -Wmissing-safe-haskell-mode
118              -Wno-missing-safe-haskell-mode  -XAllowAmbiguousTypes -XApplica‐
119              tiveDo -XArrows -XBangPatterns -XBinaryLiterals -XBlockArguments
120              -XCApiFFI   -XConstrainedClassMethods   -XConstraintKinds  -XCPP
121              -XCUSKs   -XDataKinds   -XDatatypeContexts   -XDefaultSignatures
122              -XDeriveAnyClass -XDeriveDataTypeable -XDeriveFoldable -XDerive‐
123              Functor   -XDeriveGeneric    -XDeriveLift    -XDeriveTraversable
124              -XDerivingStrategies   -XDerivingVia  -XDisambiguateRecordFields
125              -XDuplicateRecordFields  -XEmptyCase  -XEmptyDataDecls  -XEmpty‐
126              DataDeriving  -XExistentialQuantification -XExplicitForAll -XEx‐
127              plicitNamespaces    -XExtendedDefaultRules    -XFlexibleContexts
128              -XFlexibleInstances  -XForeignFunctionInterface  -XFunctionalDe‐
129              pendencies  -XGADTs  -XGADTSyntax   -XGeneralisedNewtypeDeriving
130              -XGeneralizedNewtypeDeriving      -XHaskell2010      -XHaskell98
131              -XHexFloatLiterals -XImplicitParams -XImportQualifiedPost  -XIm‐
132              predicativeTypes  -XIncoherentInstances  -XInstanceSigs -XInter‐
133              ruptibleFFI -XKindSignatures -XLambdaCase  -XLiberalTypeSynonyms
134              -XMagicHash      -XMonadComprehensions     -XMonadFailDesugaring
135              -XMonoLocalBinds -XMultiParamTypeClasses  -XMultiWayIf  -XNamed‐
136              FieldPuns  -XNamedWildCards  -XNegativeLiterals -XNoImplicitPre‐
137              lude   -XNoMonomorphismRestriction    -XNondecreasingIndentation
138              -XNoPatternGuards  -XNoTraditionalRecordSyntax  -XNPlusKPatterns
139              -XNullaryTypeClasses -XNumDecimals -XNumericUnderscores  -XOver‐
140              lappingInstances  -XOverloadedLabels  -XOverloadedLists  -XOver‐
141              loadedStrings  -XPackageImports  -XParallelListComp   -XPartial‐
142              TypeSignatures  -XPatternSynonyms -XPolyKinds -XPostfixOperators
143              -XQuantifiedConstraints -XQuasiQuotes -XRank2Types  -XRankNTypes
144              -XRebindableSyntax -XRecordWildCards -XRecursiveDo -XRoleAnnota‐
145              tions -XSafe -XScopedTypeVariables -XStandaloneDeriving  -XStan‐
146              daloneKindSignatures   -XStarIsType   -XStaticPointers  -XStrict
147              -XStrictData -XTemplateHaskell -XTemplateHaskellQuotes  -XTrans‐
148              formListComp  -XTrustworthy  -XTupleSections  -XTypeApplications
149              -XTypeFamilies -XTypeFamilyDependencies -XTypeInType -XTypeOper‐
150              ators -XTypeSynonymInstances -XUnboxedSums -XUnboxedTuples -XUn‐
151              decidableInstances   -XUndecidableSuperClasses   -XUnicodeSyntax
152              -XUnliftedFFITypes -XUnliftedNewtypes -XUnsafe -XViewPatterns
153
154       Linking options
155              -c -debug -dylib-install-name ⟨path⟩ -dynamic -dynload -eventlog
156              -fno-embed-manifest -fno-gen-manifest -fno-shared-implib -frame‐
157              work   ⟨name⟩   -framework-path   ⟨dir⟩  -fwhole-archive-hs-libs
158              -keep-cafs  -L  ⟨dir⟩  -l  ⟨lib⟩  -main-is  ⟨thing⟩  -no-hs-main
159              -no-rtsopts-suggestions  -package  ⟨name⟩  -pie  -rdynamic  -rt‐
160              sopts[=⟨none|some|all|ignore|ignoreAll⟩] -shared -split-sections
161              -static -staticlib -threaded -with-rtsopts=⟨opts⟩
162
163       Miscellaneous options
164              -fexternal-interpreter -fglasgow-exts -fno-glasgow-exts -ghcver‐
165              sion-file ⟨path to ghcversion.h⟩ -H ⟨size⟩ -j[⟨n⟩]
166
167       Modes of operation
168              --frontend  ⟨module⟩  --help  -?  --info  --interactive   --make
169              --mk-dll  --numeric-version  --print-libdir  --show-iface ⟨file⟩
170              --show-options   --supported-extensions    --supported-languages
171              --version -V -e ⟨expr⟩ -M
172
173       Individual optimizations
174              -fasm-shortcutting  -fno-asm-shortcutting  -fbinary-blob-thresh‐
175              old=⟨n⟩  -fblock-layout-cfg  -fno-block-layout-cfg  -fblock-lay‐
176              out-weightless     -fno-block-layout-weightless     -fblock-lay‐
177              out-weights    -fcall-arity    -fno-call-arity    -fcase-folding
178              -fno-case-folding  -fcase-merge  -fno-case-merge -fcmm-elim-com‐
179              mon-blocks -fno-cmm-elim-common-blocks -fcmm-sink  -fno-cmm-sink
180              -fcpr-anal        -fno-cpr-anal        -fcross-module-specialise
181              -fno-cross-module-specialise   -fcse   -fno-cse    -fdicts-cheap
182              -fno-dicts-cheap         -fdicts-strict        -fno-dicts-strict
183              -fdmd-tx-dict-sel    -fno-dmd-tx-dict-sel     -fdo-eta-reduction
184              -fno-do-eta-reduction                  -fdo-lambda-eta-expansion
185              -fno-do-lambda-eta-expansion  -feager-blackholing   -fenable-re‐
186              write-rules     -fno-enable-rewrite-rules     -fexcess-precision
187              -fno-excess-precision -fexitification  -fno-exitification  -fex‐
188              pose-all-unfoldings     -fno-expose-all-unfoldings    -ffloat-in
189              -fno-float-in -ffull-laziness -fno-full-laziness  -ffun-to-thunk
190              -fno-fun-to-thunk   -fignore-asserts  -fno-ignore-asserts  -fig‐
191              nore-interface-pragmas             -fno-ignore-interface-pragmas
192              -flate-dmd-anal       -fno-late-dmd-anal       -flate-specialise
193              -fno-late-specialise -fliberate-case -fno-liberate-case -fliber‐
194              ate-case-threshold=⟨n⟩              -fno-liberate-case-threshold
195              -fllvm-pass-vectors-in-regs       -fno-llvm-pass-vectors-in-regs
196              -floopification  -fno-loopification  -fmax-inline-alloc-size=⟨n⟩
197              -fmax-inline-memcpy-insns=⟨n⟩      -fmax-inline-memset-insns=⟨n⟩
198              -fmax-simplifier-iterations=⟨n⟩     -fmax-uncovered-patterns=⟨n⟩
199              -fmax-worker-args=⟨n⟩    -fno-opt-coercion     -fno-pre-inlining
200              -fno-state-hack     -fomit-interface-pragmas    -fno-omit-inter‐
201              face-pragmas -fomit-yields  -fno-omit-yields  -foptimal-applica‐
202              tive-do      -fno-optimal-applicative-do      -fpedantic-bottoms
203              -fno-pedantic-bottoms -fregs-graph -fno-regs-graph -fregs-itera‐
204              tive   -fno-regs-iterative   -fsimpl-tick-factor=⟨n⟩   -fsimpli‐
205              fier-phases=⟨n⟩ -fsolve-constant-dicts -fno-solve-constant-dicts
206              -fspec-constr      -fno-spec-constr      -fspec-constr-count=⟨n⟩
207              -fno-spec-constr-count -fspec-constr-keen  -fno-spec-constr-keen
208              -fspec-constr-threshold=⟨n⟩   -fno-spec-constr-threshold  -fspe‐
209              cialise  -fno-specialise   -fspecialise-aggressively   -fno-spe‐
210              cialise-aggressively            -fstatic-argument-transformation
211              -fno-static-argument-transformation    -fstg-cse    -fno-stg-cse
212              -fstg-lift-lams     -fno-stg-lift-lams     -fstg-lift-lams-known
213              -fno-stg-lift-lams-known            -fstg-lift-lams-non-rec-args
214              -fno-stg-lift-lams-non-rec-args-any     -fstg-lift-lams-rec-args
215              -fno-stg-lift-lams-rec-args-any   -fstrictness   -fno-strictness
216              -fstrictness-before=⟨n⟩   -funbox-small-strict-fields   -fno-un‐
217              box-small-strict-fields      -funbox-strict-fields      -fno-un‐
218              box-strict-fields  -funfolding-creation-threshold=⟨n⟩  -funfold‐
219              ing-dict-discount=⟨n⟩   -funfolding-fun-discount=⟨n⟩   -funfold‐
220              ing-keeness-factor=⟨n⟩             -funfolding-use-threshold=⟨n⟩
221              -fworker-wrapper
222
223       Optimization levels
224              -O -O1 -O0 -O0 -O2 -O0 -O⟨n⟩ -O0
225
226       Package options
227              -clear-package-db -distrust ⟨pkg⟩ -distrust-all-packages -fpack‐
228              age-trust  -global-package-db  -hide-all-packages  -hide-package
229              ⟨pkg⟩     -ignore-package      ⟨pkg⟩      -no-auto-link-packages
230              -no-global-package-db  -no-user-package-db -package ⟨pkg⟩ -pack‐
231              age-db ⟨file⟩ -package-env ⟨file⟩|⟨name⟩  -package-id  ⟨unit-id⟩
232              -this-unit-id ⟨unit-id⟩ -trust ⟨pkg⟩ -user-package-db
233
234       Phases of compilation
235              -C -c -E -F -S -x ⟨suffix⟩
236
237       Overriding external programs
238              -pgma  ⟨cmd⟩  -pgmc  ⟨cmd⟩ -pgmdll ⟨cmd⟩ -pgmF ⟨cmd⟩ -pgmi ⟨cmd⟩
239              -pgminstall_name_tool ⟨cmd⟩ -pgmL ⟨cmd⟩ -pgml ⟨cmd⟩ -pgmlc ⟨cmd⟩
240              -pgmlibtool  ⟨cmd⟩  -pgmlm  ⟨cmd⟩  -pgmlo  ⟨cmd⟩ -pgmotool ⟨cmd⟩
241              -pgmP ⟨cmd⟩ -pgms ⟨cmd⟩ -pgmwindres ⟨cmd⟩
242
243       Phase-specific options
244              -opta ⟨option⟩ -optc ⟨option⟩ -optcxx ⟨option⟩ -optdll  ⟨option⟩
245              -optF  ⟨option⟩  -opti  ⟨option⟩  -optL  ⟨option⟩ -optl ⟨option⟩
246              -optlc ⟨option⟩ -optlm ⟨option⟩ -optlo ⟨option⟩  -optP  ⟨option⟩
247              -optwindres ⟨option⟩ -pgmc-supports-no-pie
248
249       Platform-specific options
250              -mbmi2 -msse2 -msse4.2
251
252       Compiler plugins
253              -fclear-plugins  -fplugin-opt=⟨module⟩:⟨args⟩ -fplugin-trustwor‐
254              thy -fplugin=⟨module⟩ -hide-all-plugin-packages  -plugin-package
255              ⟨pkg⟩ -plugin-package-id ⟨pkg-id⟩
256
257       Profiling
258              -fno-prof-auto     -fprof-auto     -fno-prof-cafs    -fprof-cafs
259              -fno-prof-count-entries     -fprof-count-entries     -fprof-auto
260              -fno-prof-auto       -fprof-auto-calls      -fno-prof-auto-calls
261              -fprof-auto-exported       -fno-prof-auto        -fprof-auto-top
262              -fno-prof-auto -fprof-cafs -fno-prof-cafs -prof -ticky
263
264       Program coverage
265              -fhpc
266
267       Recompilation checking
268              -fforce-recomp  -fno-force-recomp  -fignore-hpc-changes -fno-ig‐
269              nore-hpc-changes     -fignore-optim-changes      -fno-ignore-op‐
270              tim-changes
271
272       Redirecting output
273              --exclude-module=⟨file⟩  -ddump-mod-cycles  -dep-makefile ⟨file⟩
274              -dep-suffix ⟨suffix⟩ -dumpdir ⟨dir⟩ -hcsuf ⟨suffix⟩ -hidir ⟨dir⟩
275              -hiedir ⟨dir⟩ -hiesuf ⟨suffix⟩ -hisuf ⟨suffix⟩ -include-cpp-deps
276              -include-pkg-deps -o ⟨file⟩ -odir ⟨dir⟩ -ohi ⟨file⟩ -osuf  ⟨suf‐
277              fix⟩ -outputdir ⟨dir⟩ -stubdir ⟨dir⟩
278
279       Temporary files
280              -tmpdir ⟨dir⟩
281
282       Verbosity options
283              -fabstract-refinement-hole-fits            -fno-abstract-refine‐
284              ment-hole-fits   -fdefer-diagnostics    -fdiagnostics-color=⟨al‐
285              ways|auto|never⟩      -fdiagnostics-show-caret     -fno-diagnos‐
286              tics-show-caret -ferror-spans  -fhide-source-paths  -fkeep-going
287              -fmax-refinement-hole-fits=⟨n⟩     -fno-max-refinement-hole-fits
288              -fmax-relevant-binds=⟨n⟩                 -fno-max-relevant-binds
289              -fmax-valid-hole-fits=⟨n⟩               -fno-max-valid-hole-fits
290              -fno-show-valid-hole-fits              -fno-sort-valid-hole-fits
291              -fsort-valid-hole-fits    -fprint-axiom-incomps   -fno-print-ax‐
292              iom-incomps -fprint-equality-relations -fno-print-equality-rela‐
293              tions   -fprint-expanded-synonyms   -fno-print-expanded-synonyms
294              -fprint-explicit-coercions         -fno-print-explicit-coercions
295              -fprint-explicit-foralls -fno-print-explicit-foralls -fprint-ex‐
296              plicit-kinds   -fno-print-explicit-kinds   -fprint-explicit-run‐
297              time-reps -fno-print-explicit-runtime-reps -fprint-potential-in‐
298              stances -fno-print-potential-instances -fprint-typechecker-elab‐
299              oration  -fno-print-typechecker-elaboration -fprint-unicode-syn‐
300              tax  -fno-print-unicode-syntax  -frefinement-level-hole-fits=⟨n⟩
301              -fno-refinement-level-hole-fits     -freverse-errors    -fno-re‐
302              verse-errors                            -fshow-docs-of-hole-fits
303              -fno-show-docs-of-hole-fits              -fshow-hole-constraints
304              -fshow-hole-matches-of-hole-fits
305              -fno-show-hole-matches-of-hole-fits                -fshow-prove‐
306              nance-of-hole-fits             -fno-show-provenance-of-hole-fits
307              -fshow-type-app-of-hole-fits     -fno-show-type-app-of-hole-fits
308              -fshow-type-app-vars-of-hole-fits
309              -fno-show-type-app-vars-of-hole-fits    -fshow-type-of-hole-fits
310              -fno-type-of-hole-fits -funclutter-valid-hole-fits  -Rghc-timing
311              -v -v⟨n⟩
312
313       Warnings
314              -fdefer-out-of-scope-variables -fno-defer-out-of-scope-variables
315              -fdefer-type-errors  -fno-defer-type-errors  -fdefer-typed-holes
316              -fno-defer-typed-holes    -fenable-th-splice-warnings   -fno-en‐
317              able-th-splices -fhelpful-errors  -fno-helpful-errors  -fmax-pm‐
318              check-models=⟨n⟩  -fshow-warning-groups -fno-show-warning-groups
319              -fvia-C  -W  -w   -w   -Wall   -w   -Wall-missed-specialisations
320              -Wno-all-missed-specialisations   -Wcompat   -Wno-compat  -Wcom‐
321              pat-unqualified-imports          -Wno-compat-unqualified-imports
322              -Wcpp-undef      -Wdeferred-out-of-scope-variables      -Wno-de‐
323              ferred-out-of-scope-variables  -Wdeferred-type-errors   -Wno-de‐
324              ferred-type-errors    -Wdeprecated-flags   -Wno-deprecated-flags
325              -Wdeprecations -Wno-deprecations -Wderiving-defaults -Wno-deriv‐
326              ing-defaults   -Wdodgy-exports  -Wno-dodgy-exports  -Wdodgy-for‐
327              eign-imports      -Wno-dodgy-foreign-import      -Wdodgy-imports
328              -Wno-dodgy-imports  -Wduplicate-constraints  -Wno-duplicate-con‐
329              straints -Wduplicate-exports -Wno-duplicate-exports -Wempty-enu‐
330              merations  -Wno-empty-enumerations  -Werror  -Wwarn -Weverything
331              -Whi-shadowing  -Wno-hi-shadowing  -Widentities  -Wno-identities
332              -Wimplicit-kind-vars  -Wno-implicit-kind-vars -Wimplicit-prelude
333              -Wno-implicit-prelude -Winaccessible-code -Wno-inaccessible-code
334              -Wincomplete-patterns      -Wno-incomplete-patterns     -Wincom‐
335              plete-record-updates   -Wno-incomplete-record-updates   -Wincom‐
336              plete-uni-patterns       -Wno-incomplete-uni-patterns      -Win‐
337              line-rule-shadowing   -Wno-inline-rule-shadowing    -Wmissed-ex‐
338              tra-shared-lib -Wno-missed-extra-shared-lib -Wmissed-specialisa‐
339              tions -Wno-missed-specialisations  -Wmissing-deriving-strategies
340              -Wno-missing-deriving-strategies          -Wmissing-export-lists
341              -fnowarn-missing-export-lists      -Wmissing-exported-signatures
342              -Wno-missing-exported-signatures         -Wmissing-exported-sigs
343              -Wno-missing-exported-sigs -Wmissing-fields  -Wno-missing-fields
344              -Wmissing-home-modules  -Wno-missing-home-modules  -Wmissing-im‐
345              port-lists -fnowarn-missing-import-lists  -Wmissing-local-signa‐
346              tures     -Wno-missing-local-signatures     -Wmissing-local-sigs
347              -Wno-missing-local-sigs  -Wmissing-methods  -Wno-missing-methods
348              -Wmissing-monadfail-instances   -Wno-missing-monadfail-instances
349              -Wmissing-pattern-synonym-signatures   -Wno-missing-pattern-syn‐
350              onym-signatures   -Wmissing-signatures   -Wno-missing-signatures
351              -Wmonomorphism-restriction         -Wno-monomorphism-restriction
352              -Wname-shadowing -Wno-name-shadowing -Wno-compat -Wcompat -Wnon‐
353              canonical-monad-instances      -Wno-noncanonical-monad-instances
354              -Wnoncanonical-monadfail-instances      -Wno-noncanonical-monad‐
355              fail-instances  -Wnoncanonical-monoid-instances  -Wno-noncanoni‐
356              cal-monoid-instances  -Worphans -Wno-orphans -Woverflowed-liter‐
357              als -Wno-overflowed-literals  -Woverlapping-patterns  -Wno-over‐
358              lapping-patterns   -Wpartial-fields  -Wno-partial-fields  -Wpar‐
359              tial-type-signatures    -Wno-partial-type-signatures    -Wredun‐
360              dant-constraints       -Wno-redundant-constraints       -Wredun‐
361              dant-record-wildcards   -Wno-redundant-record-wildcards   -Wsafe
362              -Wno-safe  -Wsemigroup  -Wno-semigroup -Wsimplifiable-class-con‐
363              straints -Wno-simplifiable-class-constraints  -Wspace-after-bang
364              -Wno-missing-space-after-bang   -Wstar-binder   -Wno-star-binder
365              -Wstar-is-type -Wno-star-is-type  -Wtabs  -Wno-tabs  -Wtrustwor‐
366              thy-safe     -Wno-safe     -Wtype-defaults    -Wno-type-defaults
367              -Wtyped-holes    -Wno-typed-holes     -Wunbanged-strict-patterns
368              -Wno-unbanged-strict-patterns   -Wunrecognised-pragmas  -Wno-un‐
369              recognised-pragmas  -Wunrecognised-warning-flags   -Wno-unrecog‐
370              nised-warning-flags   -Wunsafe  -Wno-unsafe  -Wunsupported-call‐
371              ing-conventions  -Wno-unsupported-calling-conventions   -Wunsup‐
372              ported-llvm-version                -Wno-monomorphism-restriction
373              -Wunticked-promoted-constructors     -Wno-unticked-promoted-con‐
374              structors   -Wunused-binds   -Wno-unused-binds  -Wunused-do-bind
375              -Wno-unused-do-bind     -Wunused-foralls     -Wno-unused-foralls
376              -Wunused-imports     -Wno-unused-imports    -Wunused-local-binds
377              -Wno-unused-local-binds   -Wunused-matches   -Wno-unused-matches
378              -Wunused-packages   -Wno-unused-packages  -Wunused-pattern-binds
379              -Wno-unused-pattern-binds   -Wunused-record-wildcards   -Wno-un‐
380              used-record-wildcards  -Wunused-top-binds  -Wno-unused-top-binds
381              -Wunused-type-patterns -Wno-unused-type-patterns -Wwarn  -Werror
382              -Wwarnings-deprecations               -Wno-warnings-deprecations
383              -Wwrong-do-bind -Wno-wrong-do-bind
384
385   Code generation
386       -dynamic-too
387              Build dynamic object files as well as static object files during
388              compilation
389
390       -fasm  Use the native code generator
391
392       -fbyte-code
393              Generate byte-code
394
395       -fexternal-dynamic-refs
396              Generate code for linking against dynamic libraries
397
398       -fllvm Compile using the LLVM code generator
399
400       -fno-code
401              Omit code generation
402
403       -fobject-code
404              Generate object code
405
406       -fPIC  Generate position-independent code (where available)
407
408       -fPIE  Generate  code  for  a  position-independent  executable  (where
409              available)
410
411       -fwrite-interface
412              Always write interface files
413
414   Debugging the compiler
415       -dcmm-lint
416              C-\- pass sanity checking
417
418       -dcore-lint
419              Turn on internal sanity checking
420
421       -ddump-asm
422              Dump final assembly
423
424       -ddump-asm-expanded
425              Dump the result of the synthetic instruction expansion pass.
426
427       -ddump-asm-liveness
428              Dump assembly augmented with register liveness
429
430       -ddump-asm-native
431              Dump initial assembly
432
433       -ddump-asm-regalloc
434              Dump the result of register allocation
435
436       -ddump-asm-regalloc-stages
437              Dump the build/spill stages of the -fregs-graph register alloca‐
438              tor.
439
440       -ddump-asm-stats
441              Dump statistics from the register allocator.
442
443       -ddump-bcos
444              Dump interpreter byte code
445
446       -ddump-cfg-weights
447              Dump the assumed weights of the CFG.
448
449       -ddump-cmm
450              Dump the final C-\- output
451
452       -ddump-cmm-caf
453              Dump the results of the C-\- CAF analysis pass.
454
455       -ddump-cmm-cbe
456              Dump the results of common block elimination
457
458       -ddump-cmm-cfg
459              Dump the results of the C-\- control flow optimisation pass.
460
461       -ddump-cmm-cps
462              Dump the results of the CPS pass
463
464       -ddump-cmm-from-stg
465              Dump STG-to-C-\- output
466
467       -ddump-cmm-info
468              Dump the results of the C-\- info table augmentation pass.
469
470       -ddump-cmm-proc
471              Dump the results of proc-point analysis
472
473       -ddump-cmm-procmap
474              Dump the results of the C-\- proc-point map pass.
475
476       -ddump-cmm-raw
477              Dump raw C-\-
478
479       -ddump-cmm-sink
480              Dump the results of the C-\- sinking pass.
481
482       -ddump-cmm-sp
483              Dump the results of the C-\- stack layout pass.
484
485       -ddump-cmm-split
486              Dump the results of the C-\- proc-point splitting pass.
487
488       -ddump-cmm-switch
489              Dump the results of switch lowering passes
490
491       -ddump-cmm-verbose
492              Write output from main C-\- pipeline passes to files
493
494       -ddump-cmm-verbose-by-proc
495              Show output from main C-\- pipeline passes (grouped by proc)
496
497       -ddump-core-stats
498              Print  a one-line summary of the size of the Core program at the
499              end of the optimisation pipeline
500
501       -ddump-cse
502              Dump CSE output
503
504       -ddump-deriv
505              Dump deriving output
506
507       -ddump-ds
508              Dump desugarer output.
509
510       -ddump-ec-trace
511              Trace exhaustiveness checker
512
513       -ddump-file-prefix=⟨str⟩
514              Set the prefix of the filenames used for debugging output.
515
516       -ddump-foreign
517              Dump foreign export stubs
518
519       -ddump-hpc
520              An alias for -ddump-ticked.
521
522       -ddump-if-trace
523              Trace interface files
524
525       -ddump-inlinings
526              Dump inlining info
527
528       -ddump-json
529              Dump error messages as JSON documents
530
531       -ddump-llvm
532              Dump LLVM intermediate code.
533
534       -ddump-mod-map
535              Dump the state of the module mapping database.
536
537       -ddump-occur-anal
538              Dump occurrence analysis output
539
540       -ddump-opt-cmm
541              Dump the results of C-\- to C-\- optimising passes
542
543       -ddump-parsed
544              Dump parse tree
545
546       -ddump-parsed-ast
547              Dump parser output as a syntax tree
548
549       -ddump-prep
550              Dump prepared core
551
552       -ddump-rn
553              Dump renamer output
554
555       -ddump-rn-ast
556              Dump renamer output as a syntax tree
557
558       -ddump-rn-stats
559              Renamer stats
560
561       -ddump-rn-trace
562              Trace renamer
563
564       -ddump-rtti
565              Trace runtime type inference
566
567       -ddump-rule-firings
568              Dump rule firing info
569
570       -ddump-rule-rewrites
571              Dump detailed rule firing info
572
573       -ddump-rules
574              Dump rewrite rules
575
576       -ddump-simpl
577              Dump final simplifier output
578
579       -ddump-simpl-iterations
580              Dump output from each simplifier iteration
581
582       -ddump-simpl-stats
583              Dump simplifier stats
584
585       -ddump-spec
586              Dump specialiser output
587
588       -ddump-splices
589              Dump TH spliced expressions, and what they evaluate to
590
591       -ddump-stg
592              Show CoreToStg output
593
594       -ddump-stg-final
595              Show output of last STG pass.
596
597       -ddump-stg-unarised
598              Show unarised STG
599
600       -ddump-str-signatures
601              Dump strictness signatures
602
603       -ddump-stranal
604              Dump strictness analyser output
605
606       -ddump-tc
607              Dump typechecker output
608
609       -ddump-tc-ast
610              Dump typechecker output as a syntax tree
611
612       -ddump-tc-trace
613              Trace typechecker
614
615       -ddump-ticked
616              Dump the code instrumented by HPC (hpc).
617
618       -ddump-timings
619              Dump per-pass timing and allocation statistics
620
621       -ddump-to-file
622              Dump to files instead of stdout
623
624       -ddump-types
625              Dump type signatures
626
627       -ddump-worker-wrapper
628              Dump worker-wrapper output
629
630       -dfaststring-stats
631              Show statistics for fast string usage when finished
632
633       -dhex-word-literals
634              Print values of type Word# in hexadecimal.
635
636       -dinitial-unique=⟨s⟩
637              Start UniqSupply allocation from ⟨s⟩.
638
639       -dinline-check=⟨str⟩
640              Dump information about inlining decisions
641
642       -dno-debug-output
643              Suppress unsolicited debugging output
644
645       -dno-typeable-binds
646              Don't generate bindings for Typeable methods
647
648       -dppr-case-as-let
649              Print single alternative case expressions as strict lets.
650
651       -dppr-cols=⟨n⟩
652              Set the width of debugging output. For example -dppr-cols200
653
654       -dppr-debug
655              Turn on debug printing (more verbose)
656
657       -dppr-user-length
658              Set the depth for printing expressions in error msgs
659
660       -drule-check=⟨str⟩
661              Dump information about potential rule application
662
663       -dshow-passes
664              Print out each pass name as it happens
665
666       -dstg-lint
667              STG pass sanity checking
668
669       -dsuppress-all
670              In dumps, suppress everything (except for uniques) that is  sup‐
671              pressible.
672
673       -dsuppress-coercions
674              Suppress  the  printing  of coercions in Core dumps to make them
675              shorter
676
677       -dsuppress-idinfo
678              Suppress extended information about identifiers where  they  are
679              bound
680
681       -dsuppress-module-prefixes
682              Suppress the printing of module qualification prefixes
683
684       -dsuppress-stg-free-vars
685              Suppress the printing of closure free variable lists in STG out‐
686              put
687
688       -dsuppress-ticks
689              Suppress "ticks" in the pretty-printer output.
690
691       -dsuppress-timestamps
692              Suppress timestamps in dumps
693
694       -dsuppress-type-applications
695              Suppress type applications
696
697       -dsuppress-type-signatures
698              Suppress type signatures
699
700       -dsuppress-unfoldings
701              Suppress the printing of the stable unfolding of a  variable  at
702              its binding site
703
704       -dsuppress-uniques
705              Suppress  the printing of uniques in debug output (easier to use
706              diff)
707
708       -dsuppress-var-kinds
709              Suppress the printing of variable kinds
710
711       -dth-dec-file
712              Dump evaluated TH declarations into *.th.hs files
713
714       -dunique-increment=⟨i⟩
715              Set the increment for the generated Unique's to ⟨i⟩.
716
717       -dverbose-core2core
718              Show output from each core-to-core pass
719
720       -dverbose-stg2stg
721              Show output from each STG-to-STG pass
722
723       -falignment-sanitisation
724              Compile with alignment checks for all info table dereferences.
725
726       -fcatch-bottoms
727              Insert error expressions  after  bottoming  expressions;  useful
728              when debugging the compiler.
729
730       -fllvm-fill-undef-with-garbage
731              Intruct LLVM to fill dead STG registers with garbage
732
733       -fproc-alignment
734              Align functions at given boundary.
735
736       -g     Produce  DWARF  debug information in compiled object files.  ⟨n⟩
737              can be 0, 1, or 2, with higher numbers producing richer  output.
738              If ⟨n⟩ is omitted, level 2 is assumed.
739
740   C pre-processor
741       -cpp   Run the C pre-processor on Haskell source files
742
743       -D⟨symbol⟩[=⟨value⟩]
744              Define a symbol in the C pre-processor
745
746       -I⟨dir⟩
747              Add ⟨dir⟩ to the directory search list for #include files
748
749       -U⟨symbol⟩
750              Undefine a symbol in the C pre-processor
751
752   Finding imports
753       -i     Empty the import directory list
754
755       -i⟨dir⟩[:⟨dir⟩]*
756              add ⟨dir⟩, ⟨dir2⟩, etc. to import path
757
758   Interactive mode
759       -fbreak-on-error
760              Break on uncaught exceptions and errors
761
762       -fbreak-on-exception
763              Break on any exception thrown
764
765       -fghci-hist-size=⟨n⟩
766              Set the number of entries GHCi keeps for :history.  See ghci-de‐
767              bugger.
768
769       -fghci-leak-check
770              (Debugging only) check for space leaks when loading new  modules
771              in GHCi.
772
773       -flocal-ghci-history
774              Use   current  directory  for  the  GHCi  command  history  file
775              .ghci-history.
776
777       -fno-it
778              No longer set the special variable it.
779
780       -fprint-bind-result
781              Turn on printing of binding results in GHCi
782
783       -fprint-evld-with-show
784              Instruct :print to use Show instances where possible.
785
786       -fshow-loaded-modules
787              Show the names of modules that GHCi loaded after  a  :load  com‐
788              mand.
789
790       -ghci-script
791              Read additional .ghci files
792
793       -ignore-dot-ghci
794              Disable reading of .ghci files
795
796       -interactive-print ⟨name⟩
797              Select the function to use for printing evaluated expressions in
798              GHCi
799
800   Interface files
801       --show-iface ⟨file⟩
802              See modes.
803
804       -ddump-hi
805              Dump the new interface to stdout
806
807       -ddump-hi-diffs
808              Show the differences vs. the old interface
809
810       -ddump-minimal-imports
811              Dump a minimal set of imports
812
813   Keeping intermediate files
814       -keep-hc-file
815              Retain intermediate .hc files.
816
817       -keep-hi-files
818              Retain intermediate .hi files (the default).
819
820       -keep-hscpp-file
821              Retain intermediate .hscpp files.
822
823       -keep-llvm-file
824              Retain intermediate LLVM .ll files.  Implies -fllvm.
825
826       -keep-o-files
827              Retain intermediate .o files (the default).
828
829       -keep-s-file
830              Retain intermediate .s files.
831
832       -keep-tmp-files
833              Retain all intermediate temporary files.
834
835   Language options
836       -fno-safe-haskell
837              Disable Safe Haskell
838
839       -fsort-by-size-hole-fits
840              Sort valid hole fits by size.
841
842       -fsort-by-subsumption-hole-fits
843              Sort valid hole fits by subsumption.
844
845       -Winferred-safe-imports
846              warn when an explicitly Safe Haskell module imports  a  Safe-In‐
847              ferred one
848
849       -Wmissing-safe-haskell-mode
850              warn when the Safe Haskell mode is not explicitly specified.
851
852       -XAllowAmbiguousTypes
853              Allow  the user to write ambiguous types, and the type inference
854              engine to infer them.
855
856       -XApplicativeDo
857              Enable Applicative do-notation desugaring
858
859       -XArrows
860              Enable arrow notation extension
861
862       -XBangPatterns
863              Enable bang patterns.
864
865       -XBinaryLiterals
866              Enable support for binary literals.
867
868       -XBlockArguments
869              Allow do blocks and other constructs as function arguments.
870
871       -XCApiFFI
872              Enable the CAPI calling convention.
873
874       -XConstrainedClassMethods
875              Enable constrained class methods.
876
877       -XConstraintKinds
878              Enable a kind of constraints.
879
880       -XCPP  Enable the C preprocessor.
881
882       -XCUSKs
883              Enable detection of complete user-supplied kind signatures.
884
885       -XDataKinds
886              Enable datatype promotion.
887
888       -XDatatypeContexts
889              Allow contexts on data types.
890
891       -XDefaultSignatures
892              Enable default signatures.
893
894       -XDeriveAnyClass
895              Enable deriving for any class.
896
897       -XDeriveDataTypeable
898              Enable deriving for the Data class.  Implied by (deprecated) Au‐
899              toDeriveTypeable.
900
901       -XDeriveFoldable
902              Enable  deriving  for  the  Foldable  class.  Implied by Derive‐
903              Traversable.
904
905       -XDeriveFunctor
906              Enable deriving for  the  Functor  class.   Implied  by  Derive‐
907              Traversable.
908
909       -XDeriveGeneric
910              Enable deriving for the Generic class.
911
912       -XDeriveLift
913              Enable deriving for the Lift class
914
915       -XDeriveTraversable
916              Enable  deriving for the Traversable class.  Implies DeriveFunc‐
917              tor and DeriveFoldable.
918
919       -XDerivingStrategies
920              Enables deriving strategies.
921
922       -XDerivingVia
923              Enable deriving instances via types of the same  runtime  repre‐
924              sentation.  Implies DerivingStrategies.
925
926       -XDisambiguateRecordFields
927              Enable record field disambiguation.  Implied by RecordWildCards.
928
929       -XDuplicateRecordFields
930              Allow definition of record types with identically-named fields.
931
932       -XEmptyCase
933              Allow empty case alternatives.
934
935       -XEmptyDataDecls
936              Allow definition of empty data types.
937
938       -XEmptyDataDeriving
939              Allow deriving instances of standard type classes for empty data
940              types.
941
942       -XExistentialQuantification
943              Enable liberalised type synonyms.
944
945       -XExplicitForAll
946              Enable explicit universal quantification.   Implied  by  Scoped‐
947              TypeVariables,   LiberalTypeSynonyms,  RankNTypes  and  Existen‐
948              tialQuantification.
949
950       -XExplicitNamespaces
951              Enable using the keyword type to specify the  namespace  of  en‐
952              tries  in imports and exports (explicit-namespaces).  Implied by
953              TypeOperators and TypeFamilies.
954
955       -XExtendedDefaultRules
956              Use GHCi's extended default rules in a normal module.
957
958       -XFlexibleContexts
959              Enable flexible contexts.
960
961       -XFlexibleInstances
962              Enable flexible instances.  Implies TypeSynonymInstances.
963
964       -XForeignFunctionInterface
965              Enable foreign function interface.
966
967       -XFunctionalDependencies
968              Enable functional dependencies.  Implies MultiParamTypeClasses.
969
970       -XGADTs
971              Enable generalised algebraic data types.  Implies GADTSyntax and
972              MonoLocalBinds.
973
974       -XGADTSyntax
975              Enable generalised algebraic data type syntax.
976
977       -XGeneralisedNewtypeDeriving
978              Enable newtype deriving.
979
980       -XGeneralizedNewtypeDeriving
981              Enable newtype deriving.
982
983       -XHaskell2010
984              Use the Haskell 2010 language variant.
985
986       -XHaskell98
987              Use the Haskell 2010 language variant.
988
989       -XHexFloatLiterals
990              Enable support for hexadecimal floating point literals.
991
992       -XImplicitParams
993              Enable Implicit Parameters.
994
995       -XImportQualifiedPost
996              ImportQualifiedPost allows the syntax import M qualified
997
998       -XImpredicativeTypes
999              Enable impredicative types.  Implies RankNTypes.
1000
1001       -XIncoherentInstances
1002              Enable incoherent instances.  Implies OverlappingInstances.
1003
1004       -XInstanceSigs
1005              Enable instance signatures.
1006
1007       -XInterruptibleFFI
1008              Enable interruptible FFI.
1009
1010       -XKindSignatures
1011              Enable kind signatures.  Implied by TypeFamilies and PolyKinds.
1012
1013       -XLambdaCase
1014              Enable lambda-case expressions.
1015
1016       -XLiberalTypeSynonyms
1017              Enable liberalised type synonyms.
1018
1019       -XMagicHash
1020              Allow # as a postfix modifier on identifiers.
1021
1022       -XMonadComprehensions
1023              Enable monad comprehensions.
1024
1025       -XMonadFailDesugaring
1026              Enable monadfail desugaring.
1027
1028       -XMonoLocalBinds
1029              Enable  do  not generalise local bindings.  Implied by TypeFami‐
1030              lies and GADTs.
1031
1032       -XMultiParamTypeClasses
1033              Enable multi parameter type classes.  Implied  by  FunctionalDe‐
1034              pendencies.
1035
1036       -XMultiWayIf
1037              Enable multi-way if-expressions.
1038
1039       -XNamedFieldPuns
1040              Enable record puns.
1041
1042       -XNamedWildCards
1043              Enable named wildcards.
1044
1045       -XNegativeLiterals
1046              Enable support for negative literals.
1047
1048       -XNoImplicitPrelude
1049              Don't implicitly import Prelude.  Implied by RebindableSyntax.
1050
1051       -XNoMonomorphismRestriction
1052              Disable the monomorphism restriction.
1053
1054       -XNondecreasingIndentation
1055              Allow nested contexts to be at the same indentation level as its
1056              enclosing context.
1057
1058       -XNoPatternGuards
1059              Disable pattern guards.  Implied by Haskell98.
1060
1061       -XNoTraditionalRecordSyntax
1062              Disable support for traditional record syntax (as  supported  by
1063              Haskell 98) C {f = x}
1064
1065       -XNPlusKPatterns
1066              Enable support for n+k patterns.  Implied by Haskell98.
1067
1068       -XNullaryTypeClasses
1069              Deprecated,  does  nothing.  nullary (no parameter) type classes
1070              are now enabled using MultiParamTypeClasses.
1071
1072       -XNumDecimals
1073              Enable support for 'fractional' integer literals.
1074
1075       -XNumericUnderscores
1076              Enable support for numeric underscores.
1077
1078       -XOverlappingInstances
1079              Enable overlapping instances.
1080
1081       -XOverloadedLabels
1082              Enable overloaded labels.
1083
1084       -XOverloadedLists
1085              Enable overloaded lists.
1086
1087       -XOverloadedStrings
1088              Enable overloaded string literals.
1089
1090       -XPackageImports
1091              Enable package-qualified imports.
1092
1093       -XParallelListComp
1094              Enable parallel list comprehensions.
1095
1096       -XPartialTypeSignatures
1097              Enable partial type signatures.
1098
1099       -XPatternSynonyms
1100              Enable pattern synonyms.
1101
1102       -XPolyKinds
1103              Enable kind polymorphism.  Implies KindSignatures.
1104
1105       -XPostfixOperators
1106              Enable postfix operators.
1107
1108       -XQuantifiedConstraints
1109              Allow forall quantifiers in constraints.
1110
1111       -XQuasiQuotes
1112              Enable quasiquotation.
1113
1114       -XRank2Types
1115              Enable rank-2 types.  Synonym for RankNTypes.
1116
1117       -XRankNTypes
1118              Enable rank-N types.  Implied by ImpredicativeTypes.
1119
1120       -XRebindableSyntax
1121              Employ rebindable syntax.  Implies NoImplicitPrelude.
1122
1123       -XRecordWildCards
1124              Enable record wildcards.  Implies DisambiguateRecordFields.
1125
1126       -XRecursiveDo
1127              Enable recursive do (mdo) notation.
1128
1129       -XRoleAnnotations
1130              Enable role annotations.
1131
1132       -XSafe Enable the Safe Haskell Safe mode.
1133
1134       -XScopedTypeVariables
1135              Enable lexically-scoped type variables.
1136
1137       -XStandaloneDeriving
1138              Enable standalone deriving.
1139
1140       -XStandaloneKindSignatures
1141              Allow the use of standalone kind signatures.
1142
1143       -XStarIsType
1144              Treat * as Data.Kind.Type.
1145
1146       -XStaticPointers
1147              Enable static pointers.
1148
1149       -XStrict
1150              Make bindings in the current module strict by default.
1151
1152       -XStrictData
1153              Enable default strict datatype fields.
1154
1155       -XTemplateHaskell
1156              Enable Template Haskell.
1157
1158       -XTemplateHaskellQuotes
1159              Enable quotation subset of Template Haskell.
1160
1161       -XTransformListComp
1162              Enable generalised list comprehensions.
1163
1164       -XTrustworthy
1165              Enable the Safe Haskell Trustworthy mode.
1166
1167       -XTupleSections
1168              Enable tuple sections.
1169
1170       -XTypeApplications
1171              Enable type application syntax in terms and types.
1172
1173       -XTypeFamilies
1174              Enable type families.   Implies  ExplicitNamespaces,  KindSigna‐
1175              tures, and MonoLocalBinds.
1176
1177       -XTypeFamilyDependencies
1178              Enable injective type families.  Implies TypeFamilies.
1179
1180       -XTypeInType
1181              Deprecated. Enable kind polymorphism and datatype promotion.
1182
1183       -XTypeOperators
1184              Enable type operators.  Implies ExplicitNamespaces.
1185
1186       -XTypeSynonymInstances
1187              Enable  type synonyms in instance heads.  Implied by FlexibleIn‐
1188              stances.
1189
1190       -XUnboxedSums
1191              Enable unboxed sums.
1192
1193       -XUnboxedTuples
1194              Enable the use of unboxed tuple syntax.
1195
1196       -XUndecidableInstances
1197              Enable undecidable instances.
1198
1199       -XUndecidableSuperClasses
1200              Allow all superclass constraints, including those that  may  re‐
1201              sult in non-termination of the typechecker.
1202
1203       -XUnicodeSyntax
1204              Enable unicode syntax.
1205
1206       -XUnliftedFFITypes
1207              Enable unlifted FFI types
1208
1209       -XUnliftedNewtypes
1210              Enable unlifted newtypes.
1211
1212       -XUnsafe
1213              Enable Safe Haskell Unsafe mode.
1214
1215       -XViewPatterns
1216              Enable view patterns.
1217
1218   Linking options
1219       -c     Stop after generating object (.o) file
1220
1221       -debug Use the debugging runtime
1222
1223       -dylib-install-name ⟨path⟩
1224              Set  the  install  name  (via  -install_name  passed  to Apple's
1225              linker), specifying the full install path of the  library  file.
1226              Any  libraries  or executables that link with it later will pick
1227              up that path as their runtime search  location  for  it.   (Dar‐
1228              win/OS X only)
1229
1230       -dynamic
1231              Build dynamically-linked object files and executables
1232
1233       -dynload
1234              Selects one of a number of modes for finding shared libraries at
1235              runtime.
1236
1237       -eventlog
1238              Enable runtime event tracing
1239
1240       -fno-embed-manifest
1241              Do not embed the manifest in the executable (Windows only)
1242
1243       -fno-gen-manifest
1244              Do not generate a manifest file (Windows only)
1245
1246       -fno-shared-implib
1247              Don't generate an import library for a DLL (Windows only)
1248
1249       -framework ⟨name⟩
1250              On Darwin/OS X/iOS only, link in the framework ⟨name⟩. This  op‐
1251              tion corresponds to the -framework option for Apple's Linker.
1252
1253       -framework-path ⟨dir⟩
1254              On  Darwin/OS  X/iOS  only, add ⟨dir⟩ to the list of directories
1255              searched for frameworks. This option corresponds to the  -F  op‐
1256              tion for Apple's Linker.
1257
1258       -fwhole-archive-hs-libs
1259              When   linking  a  binary  executable,  this  inserts  the  flag
1260              -Wl,--whole-archive before any -l flags for  Haskell  libraries,
1261              and -Wl,--no-whole-archive afterwards
1262
1263       -keep-cafs
1264              Do not garbage-collect CAFs (top-level expressions) at runtime
1265
1266       -L ⟨dir⟩
1267              Add ⟨dir⟩ to the list of directories searched for libraries
1268
1269       -l ⟨lib⟩
1270              Link in library ⟨lib⟩
1271
1272       -main-is ⟨thing⟩
1273              Set main module and function
1274
1275       -no-hs-main
1276              Don't assume this program contains main
1277
1278       -no-rtsopts-suggestions
1279              Don't   print   RTS   suggestions   about   linking   with  -rt‐
1280              sopts[=⟨none|some|all|ignore|ignoreAll⟩].
1281
1282       -package ⟨name⟩
1283              Expose package ⟨pkg⟩
1284
1285       -pie   Instruct the  linker  to  produce  a  position-independent  exe‐
1286              cutable.
1287
1288       -rdynamic
1289              This  instructs  the  linker  to  add all symbols, not only used
1290              ones, to the dynamic symbol  table.  Currently  Linux  and  Win‐
1291              dows/MinGW32  only.  This is equivalent to using -optl -rdynamic
1292              on Linux, and -optl -export-all-symbols on Windows.
1293
1294       -rtsopts[=⟨none|some|all|ignore|ignoreAll⟩]
1295              Control whether the  RTS  behaviour  can  be  tweaked  via  com‐
1296              mand-line  flags and the GHCRTS environment variable. Using none
1297              means no RTS flags can be given; some means only  a  minimum  of
1298              safe  options can be given (the default); all (or no argument at
1299              all) means that all RTS flags are permitted;  ignore  means  RTS
1300              flags  can  be  given,  but are treated as regular arguments and
1301              passed to the Haskell program as  arguments;  ignoreAll  is  the
1302              same  as  ignore,  but GHCRTS is also ignored. -rtsopts does not
1303              affect -with-rtsopts behavior; flags  passed  via  -with-rtsopts
1304              are used regardless of -rtsopts.
1305
1306       -shared
1307              Generate a shared library (as opposed to an executable)
1308
1309       -split-sections
1310              Split sections for link-time dead-code stripping
1311
1312       -static
1313              Use static Haskell libraries
1314
1315       -staticlib
1316              Generate  a  standalone  static  library  (as opposed to an exe‐
1317              cutable). This is useful when cross compiling. The  library  to‐
1318              gether  with  all its dependencies ends up in in a single static
1319              library that can be linked against.
1320
1321       -threaded
1322              Use the threaded runtime
1323
1324       -with-rtsopts=⟨opts⟩
1325              Set the default RTS options to ⟨opts⟩.
1326
1327   Miscellaneous options
1328       -fexternal-interpreter
1329              Run interpreted code in a separate process
1330
1331       -fglasgow-exts
1332              Deprecated. Enable most language  extensions;  see  options-lan‐
1333              guage for exactly which ones.
1334
1335       -ghcversion-file ⟨path to ghcversion.h⟩
1336              (GHC as a C compiler only) Use this ghcversion.h file
1337
1338       -H ⟨size⟩
1339              Set the minimum size of the heap to ⟨size⟩
1340
1341       -j[⟨n⟩]
1342              When compiling with --make, compile ⟨n⟩ modules in parallel.
1343
1344   Modes of operation
1345       --frontend ⟨module⟩
1346              run GHC with the given frontend plugin; see frontend_plugins for
1347              details.
1348
1349       --help Display help
1350
1351       --info display information about the compiler
1352
1353       --interactive
1354              Interactive mode - normally used by just running ghci; see  ghci
1355              for details.
1356
1357       --make Build a multi-module Haskell program, automatically figuring out
1358              dependencies. Likely to be much easier, and faster,  than  using
1359              make; see make-mode for details.
1360
1361       --mk-dll
1362              DLL-creation mode (Windows only)
1363
1364       --numeric-version
1365              display GHC version (numeric only)
1366
1367       --print-libdir
1368              display GHC library directory
1369
1370       --show-iface ⟨file⟩
1371              display the contents of an interface file.
1372
1373       --show-options
1374              display the supported command line options
1375
1376       --supported-extensions
1377              display the supported language extensions
1378
1379       --version
1380              display GHC version
1381
1382       -e ⟨expr⟩
1383              Evaluate expr; see eval-mode for details.
1384
1385       -M     generate  dependency information suitable for use in a Makefile;
1386              see makefile-dependencies for details.
1387
1388   Individual optimizations
1389       -fasm-shortcutting
1390              Enable shortcutting on assembly. Implied by -O2.
1391
1392       -fbinary-blob-threshold=⟨n⟩
1393              default: 500K. Tweak assembly generator for binary blobs.
1394
1395       -fblock-layout-cfg
1396              Use the new cfg based block layout algorithm.
1397
1398       -fblock-layout-weightless
1399              Ignore cfg weights for code layout.
1400
1401       -fblock-layout-weights
1402              Sets edge weights used by the new code layout algorithm.
1403
1404       -fcall-arity
1405              Enable call-arity optimisation. Implied by -O.
1406
1407       -fcase-folding
1408              Enable constant folding in case expressions. Implied by -O.
1409
1410       -fcase-merge
1411              Enable case-merging. Implied by -O.
1412
1413       -fcmm-elim-common-blocks
1414              Enable Cmm common block elimination. Implied by -O.
1415
1416       -fcmm-sink
1417              Enable Cmm sinking. Implied by -O.
1418
1419       -fcpr-anal
1420              Turn on CPR analysis in the demand analyser. Implied by -O.
1421
1422       -fcross-module-specialise
1423              Turn on specialisation of  overloaded  functions  imported  from
1424              other modules.
1425
1426       -fcse  Enable common sub-expression elimination. Implied by -O.
1427
1428       -fdicts-cheap
1429              Make dictionary-valued expressions seem cheap to the optimiser.
1430
1431       -fdicts-strict
1432              Make dictionaries strict
1433
1434       -fdmd-tx-dict-sel
1435              Use  a special demand transformer for dictionary selectors.  Al‐
1436              ways enabled by default.
1437
1438       -fdo-eta-reduction
1439              Enable eta-reduction. Implied by -O.
1440
1441       -fdo-lambda-eta-expansion
1442              Enable lambda eta-expansion. Always enabled by default.
1443
1444       -feager-blackholing
1445              Turn on eager blackholing
1446
1447       -fenable-rewrite-rules
1448              Switch on all rewrite rules (including rules generated by  auto‐
1449              matic specialisation of overloaded functions). Implied by -O.
1450
1451       -fexcess-precision
1452              Enable excess intermediate precision
1453
1454       -fexitification
1455              Enables exitification optimisation. Implied by -O.
1456
1457       -fexpose-all-unfoldings
1458              Expose  all  unfoldings,  even for very large or recursive func‐
1459              tions.
1460
1461       -ffloat-in
1462              Turn on the float-in transformation. Implied by -O.
1463
1464       -ffull-laziness
1465              Turn on full laziness (floating bindings outwards).  Implied  by
1466              -O.
1467
1468       -ffun-to-thunk
1469              Allow  worker-wrapper to convert a function closure into a thunk
1470              if the function does not use any of its arguments.  Off  by  de‐
1471              fault.
1472
1473       -fignore-asserts
1474              Ignore assertions in the source. Implied by -O.
1475
1476       -fignore-interface-pragmas
1477              Ignore pragmas in interface files. Implied by -O0 only.
1478
1479       -flate-dmd-anal
1480              Run  demand  analysis  again,  at  the end of the simplification
1481              pipeline
1482
1483       -flate-specialise
1484              Run a late specialisation pass
1485
1486       -fliberate-case
1487              Turn on the liberate-case transformation. Implied by -O2.
1488
1489       -fliberate-case-threshold=⟨n⟩
1490              default: 2000. Set the  size  threshold  for  the  liberate-case
1491              transformation to ⟨n⟩
1492
1493       -fllvm-pass-vectors-in-regs
1494              Pass vector value in vector registers for function calls
1495
1496       -floopification
1497              Turn saturated self-recursive tail-calls into local jumps in the
1498              generated assembly. Implied by -O.
1499
1500       -fmax-inline-alloc-size=⟨n⟩
1501              default: 128. Set the maximum size of inline  array  allocations
1502              to ⟨n⟩ bytes (default: 128).
1503
1504       -fmax-inline-memcpy-insns=⟨n⟩
1505              default:  32. Inline memcpy calls if they would generate no more
1506              than ⟨n⟩ pseudo instructions.
1507
1508       -fmax-inline-memset-insns=⟨n⟩
1509              default: 32. Inline memset calls if they would generate no  more
1510              than ⟨n⟩ pseudo instructions
1511
1512       -fmax-simplifier-iterations=⟨n⟩
1513              default: 4. Set the max iterations for the simplifier.
1514
1515       -fmax-uncovered-patterns=⟨n⟩
1516              default:  4.  Set  the  maximum number of patterns to display in
1517              warnings about non-exhaustive ones.
1518
1519       -fmax-worker-args=⟨n⟩
1520              default: 10. If a worker has that many arguments, none  will  be
1521              unpacked anymore.
1522
1523       -fno-opt-coercion
1524              Turn off the coercion optimiser
1525
1526       -fno-pre-inlining
1527              Turn off pre-inlining
1528
1529       -fno-state-hack
1530              Turn  off  the  state  hackwhereby  any lambda with a real-world
1531              state token as argument is considered to be single-entry.  Hence
1532              OK to inline things inside it.
1533
1534       -fomit-interface-pragmas
1535              Don't generate interface pragmas. Implied by -O0 only.
1536
1537       -fomit-yields
1538              Omit heap checks when no allocation is being performed.
1539
1540       -foptimal-applicative-do
1541              Use a slower but better algorithm for ApplicativeDo
1542
1543       -fpedantic-bottoms
1544              Make  GHC be more precise about its treatment of bottom (but see
1545              also -fno-state-hack). In particular, GHC  will  not  eta-expand
1546              through a case expression.
1547
1548       -fregs-graph
1549              Use  the graph colouring register allocator for register alloca‐
1550              tion in the native code generator. Implied by -O2.
1551
1552       -fregs-iterative
1553              Use the iterative coalescing graph colouring register  allocator
1554              in the native code generator.
1555
1556       -fsimpl-tick-factor=⟨n⟩
1557              default: 100. Set the percentage factor for simplifier ticks.
1558
1559       -fsimplifier-phases=⟨n⟩
1560              default:  2.  Set  the number of phases for the simplifier.  Ig‐
1561              nored with -O0.
1562
1563       -fsolve-constant-dicts
1564              When solving constraints, try to eagerly solve super classes us‐
1565              ing available dictionaries.
1566
1567       -fspec-constr
1568              Turn on the SpecConstr transformation. Implied by -O2.
1569
1570       -fspec-constr-count=⟨n⟩
1571              default:  3.*  Set  to ⟨n⟩ the maximum number of specialisations
1572              that will be created for any  one  function  by  the  SpecConstr
1573              transformation.
1574
1575       -fspec-constr-keen
1576              Specialize a call with an explicit constructor argument, even if
1577              the argument is not scrutinised in the body of the function
1578
1579       -fspec-constr-threshold=⟨n⟩
1580              default: 2000. Set the size threshold for the SpecConstr  trans‐
1581              formation to ⟨n⟩.
1582
1583       -fspecialise
1584              Turn on specialisation of overloaded functions. Implied by -O.
1585
1586       -fspecialise-aggressively
1587              Turn  on  specialisation  of  overloaded functions regardless of
1588              size, if unfolding is available
1589
1590       -fstatic-argument-transformation
1591              Turn on the static argument transformation.
1592
1593       -fstg-cse
1594              Enable common sub-expression elimination on the STG intermediate
1595              language
1596
1597       -fstg-lift-lams
1598              Enable late lambda lifting on the STG intermediate language. Im‐
1599              plied by -O2.
1600
1601       -fstg-lift-lams-known
1602              Allow turning known into unknown  calls  while  performing  late
1603              lambda lifting.
1604
1605       -fstg-lift-lams-non-rec-args
1606              Create top-level non-recursive functions with at most <n> param‐
1607              eters while performing late lambda lifting.
1608
1609       -fstg-lift-lams-rec-args
1610              Create top-level recursive functions with at most <n> parameters
1611              while performing late lambda lifting.
1612
1613       -fstrictness
1614              Turn   on   strictness   analysis.    Implied   by  -O.  Implies
1615              -fworker-wrapper
1616
1617       -fstrictness-before=⟨n⟩
1618              Run an additional strictness analysis  before  simplifier  phase
1619              ⟨n⟩
1620
1621       -funbox-small-strict-fields
1622              Flatten strict constructor fields with a pointer-sized represen‐
1623              tation. Implied by -O.
1624
1625       -funbox-strict-fields
1626              Flatten strict constructor fields
1627
1628       -funfolding-creation-threshold=⟨n⟩
1629              default: 750. Tweak unfolding settings.
1630
1631       -funfolding-dict-discount=⟨n⟩
1632              default: 30. Tweak unfolding settings.
1633
1634       -funfolding-fun-discount=⟨n⟩
1635              default: 60. Tweak unfolding settings.
1636
1637       -funfolding-keeness-factor=⟨n⟩
1638              default: 1.5. Tweak unfolding settings.
1639
1640       -funfolding-use-threshold=⟨n⟩
1641              default: 60. Tweak unfolding settings.
1642
1643       -fworker-wrapper
1644              Enable the worker-wrapper transformation.
1645
1646   Optimization levels
1647       -O     Enable level 1 optimisations
1648
1649       -O0    Disable optimisations (default)
1650
1651       -O2    Enable level 2 optimisations
1652
1653       -O⟨n⟩  Any -On where n > 2 is the same as -O2.
1654
1655   Package options
1656       -clear-package-db
1657              Clear the package db stack.
1658
1659       -distrust ⟨pkg⟩
1660              Expose  package  ⟨pkg⟩  and  set  it  to  be   distrusted.   See
1661              safe-haskell.
1662
1663       -distrust-all-packages
1664              Distrust all packages by default. See safe-haskell.
1665
1666       -fpackage-trust
1667              Enable  Safe Haskell trusted package requirement for trustworthy
1668              modules.
1669
1670       -global-package-db
1671              Add the global package db to the stack.
1672
1673       -hide-all-packages
1674              Hide all packages by default
1675
1676       -hide-package ⟨pkg⟩
1677              Hide package ⟨pkg⟩
1678
1679       -ignore-package ⟨pkg⟩
1680              Ignore package ⟨pkg⟩
1681
1682       -no-auto-link-packages
1683              Don't automatically link in the base and rts packages.
1684
1685       -no-global-package-db
1686              Remove the global package db from the stack.
1687
1688       -no-user-package-db
1689              Remove the user's package db from the stack.
1690
1691       -package ⟨pkg⟩
1692              Expose package ⟨pkg⟩
1693
1694       -package-db ⟨file⟩
1695              Add ⟨file⟩ to the package db stack.
1696
1697       -package-env ⟨file⟩|⟨name⟩
1698              Use the specified package environment.
1699
1700       -package-id ⟨unit-id⟩
1701              Expose package by id ⟨unit-id⟩
1702
1703       -this-unit-id ⟨unit-id⟩
1704              Compile to be part of unit (i.e. package) ⟨unit-id⟩
1705
1706       -trust ⟨pkg⟩
1707              Expose package ⟨pkg⟩ and set it to be trusted. See safe-haskell.
1708
1709       -user-package-db
1710              Add the user's package db to the stack.
1711
1712   Phases of compilation
1713       -C     Stop after generating C (.hc file)
1714
1715       -c     Stop after generating object (.o) file
1716
1717       -E     Stop after preprocessing (.hspp file)
1718
1719       -F     Enable the use of a pre-processor (set with -pgmF ⟨cmd⟩)
1720
1721       -S     Stop after generating assembly (.s file)
1722
1723       -x ⟨suffix⟩
1724              Override default behaviour for source files
1725
1726   Overriding external programs
1727       -pgma ⟨cmd⟩
1728              Use ⟨cmd⟩ as the assembler
1729
1730       -pgmc ⟨cmd⟩
1731              Use ⟨cmd⟩ as the C compiler
1732
1733       -pgmdll ⟨cmd⟩
1734              Use ⟨cmd⟩ as the DLL generator
1735
1736       -pgmF ⟨cmd⟩
1737              Use ⟨cmd⟩ as the pre-processor (with -F only)
1738
1739       -pgmi ⟨cmd⟩
1740              Use ⟨cmd⟩ as the external interpreter command.
1741
1742       -pgminstall_name_tool ⟨cmd⟩
1743              Use ⟨cmd⟩ as the program to inject runpath into mach-o dylibs on
1744              macOS
1745
1746       -pgmL ⟨cmd⟩
1747              Use ⟨cmd⟩ as the literate pre-processor
1748
1749       -pgml ⟨cmd⟩
1750              Use ⟨cmd⟩ as the linker
1751
1752       -pgmlc ⟨cmd⟩
1753              Use ⟨cmd⟩ as the LLVM compiler
1754
1755       -pgmlibtool ⟨cmd⟩
1756              Use ⟨cmd⟩ as the command for libtool (with -staticlib only).
1757
1758       -pgmlm ⟨cmd⟩
1759              Use ⟨cmd⟩ as the linker when merging object files
1760
1761       -pgmlo ⟨cmd⟩
1762              Use ⟨cmd⟩ as the LLVM optimiser
1763
1764       -pgmotool ⟨cmd⟩
1765              Use ⟨cmd⟩ as the program to inspect mach-o dylibs on macOS
1766
1767       -pgmP ⟨cmd⟩
1768              Use ⟨cmd⟩ as the C pre-processor (with -cpp only)
1769
1770       -pgms ⟨cmd⟩
1771              Use ⟨cmd⟩ as the splitter
1772
1773       -pgmwindres ⟨cmd⟩
1774              Use ⟨cmd⟩ as the program for embedding manifests on Windows.
1775
1776   Phase-specific options
1777       -opta ⟨option⟩
1778              pass ⟨option⟩ to the assembler
1779
1780       -optc ⟨option⟩
1781              pass ⟨option⟩ to the C compiler
1782
1783       -optcxx ⟨option⟩
1784              pass ⟨option⟩ to the C++ compiler
1785
1786       -optdll ⟨option⟩
1787              pass ⟨option⟩ to the DLL generator
1788
1789       -optF ⟨option⟩
1790              pass ⟨option⟩ to the custom pre-processor
1791
1792       -opti ⟨option⟩
1793              pass ⟨option⟩ to the interpreter sub-process.
1794
1795       -optL ⟨option⟩
1796              pass ⟨option⟩ to the literate pre-processor
1797
1798       -optl ⟨option⟩
1799              pass ⟨option⟩ to the linker
1800
1801       -optlc ⟨option⟩
1802              pass ⟨option⟩ to the LLVM compiler
1803
1804       -optlm ⟨option⟩
1805              pass ⟨option⟩ to the linker when merging object files.
1806
1807       -optlo ⟨option⟩
1808              pass ⟨option⟩ to the LLVM optimiser
1809
1810       -optP ⟨option⟩
1811              pass ⟨option⟩ to cpp (with -cpp only)
1812
1813       -optwindres ⟨option⟩
1814              pass ⟨option⟩ to windres.
1815
1816       -pgmc-supports-no-pie
1817              Indicate that the C compiler supports -no-pie
1818
1819   Platform-specific options
1820       -mbmi2 (x86 only) Use BMI2 for bit manipulation operations
1821
1822       -msse2 (x86 only) Use SSE2 for floating-point operations
1823
1824       -msse4.2
1825              (x86 only) Use SSE4.2 for floating-point operations
1826
1827   Compiler plugins
1828       -fclear-plugins
1829              Clear the list of active plugins
1830
1831       -fplugin-opt=⟨module⟩:⟨args⟩
1832              Give arguments to a plugin module; module must be specified with
1833              -fplugin=⟨module⟩
1834
1835       -fplugin-trustworthy
1836              Trust the used plugins and no longer mark the compiled module as
1837              unsafe
1838
1839       -fplugin=⟨module⟩
1840              Load a plugin exported by a given module
1841
1842       -hide-all-plugin-packages
1843              Hide all packages for plugins by default
1844
1845       -plugin-package ⟨pkg⟩
1846              Expose ⟨pkg⟩ for plugins
1847
1848       -plugin-package-id ⟨pkg-id⟩
1849              Expose ⟨pkg-id⟩ for plugins
1850
1851   Profiling
1852       -fno-prof-auto
1853              Disables   any   previous   -fprof-auto,   -fprof-auto-top,   or
1854              -fprof-auto-exported options.
1855
1856       -fno-prof-cafs
1857              Disables any previous -fprof-cafs option.
1858
1859       -fno-prof-count-entries
1860              Do not collect entry counts
1861
1862       -fprof-auto
1863              Auto-add SCC\ s to all bindings not marked INLINE
1864
1865       -fprof-auto-calls
1866              Auto-add SCC\ s to all call sites
1867
1868       -fprof-auto-exported
1869              Auto-add SCC\ s to all exported bindings not marked INLINE
1870
1871       -fprof-auto-top
1872              Auto-add SCC\ s to all top-level bindings not marked INLINE
1873
1874       -fprof-cafs
1875              Auto-add SCC\ s to all CAFs
1876
1877       -prof  Turn on profiling
1878
1879       -ticky Turn on ticky-ticky profiling
1880
1881   Program coverage
1882       -fhpc  Turn on Haskell program coverage instrumentation
1883
1884   Recompilation checking
1885       -fforce-recomp
1886              Turn off recompilation checking. This is implied by any -ddump-X
1887              option when compiling a single file (i.e. when using -c).
1888
1889       -fignore-hpc-changes
1890              Do  not  recompile  modules  just to match changes to HPC flags.
1891              This is especially useful for avoiding recompilation when  using
1892              GHCi, and is enabled by default for GHCi.
1893
1894       -fignore-optim-changes
1895              Do  not  recompile modules just to match changes to optimisation
1896              flags. This is especially useful for avoiding recompilation when
1897              using GHCi, and is enabled by default for GHCi.
1898
1899   Redirecting output
1900       --exclude-module=⟨file⟩
1901              Regard  ⟨file⟩  as "stable"; i.e., exclude it from having depen‐
1902              dencies on it.
1903
1904       -ddump-mod-cycles
1905              Dump module cycles
1906
1907       -dep-makefile ⟨file⟩
1908              Use ⟨file⟩ as the makefile
1909
1910       -dep-suffix ⟨suffix⟩
1911              Make  dependencies  that  declare   that   files   with   suffix
1912              .⟨suf⟩⟨osuf⟩ depend on interface files with suffix .⟨suf⟩hi
1913
1914       -dumpdir ⟨dir⟩
1915              redirect dump files
1916
1917       -hcsuf ⟨suffix⟩
1918              set the suffix to use for intermediate C files
1919
1920       -hidir ⟨dir⟩
1921              set directory for interface files
1922
1923       -hiedir ⟨dir⟩
1924              set directory for extended interface files
1925
1926       -hiesuf ⟨suffix⟩
1927              set the suffix to use for extended interface files
1928
1929       -hisuf ⟨suffix⟩
1930              set the suffix to use for interface files
1931
1932       -include-cpp-deps
1933              Include preprocessor dependencies
1934
1935       -include-pkg-deps
1936              Regard modules imported from packages as unstable
1937
1938       -o ⟨file⟩
1939              set output filename
1940
1941       -odir ⟨dir⟩
1942              set directory for object files
1943
1944       -ohi ⟨file⟩
1945              set the filename in which to put the interface
1946
1947       -osuf ⟨suffix⟩
1948              set the output file suffix
1949
1950       -outputdir ⟨dir⟩
1951              set output directory
1952
1953       -stubdir ⟨dir⟩
1954              redirect FFI stub files
1955
1956   Temporary files
1957       -tmpdir ⟨dir⟩
1958              set the directory for temporary files
1959
1960   Verbosity options
1961       -fabstract-refinement-hole-fits
1962              default:  off.  Toggles whether refinements where one or more of
1963              the holes are abstract are reported.
1964
1965       -fdefer-diagnostics
1966              Defer and group diagnostic messages by severity
1967
1968       -fdiagnostics-color=⟨always|auto|never⟩
1969              Use colors in error messages
1970
1971       -fdiagnostics-show-caret
1972              Whether to show snippets of original source code
1973
1974       -ferror-spans
1975              Output full span in error messages
1976
1977       -fhide-source-paths
1978              hide module source and object paths
1979
1980       -fkeep-going
1981              Continue compilation as far as possible on errors
1982
1983       -fmax-refinement-hole-fits=⟨n⟩
1984              default: 6. Set the maximum number of refinement hole  fits  for
1985              typed holes to display in type error messages.
1986
1987       -fmax-relevant-binds=⟨n⟩
1988              default:  6.  Set  the  maximum number of bindings to display in
1989              type error messages.
1990
1991       -fmax-valid-hole-fits=⟨n⟩
1992              default: 6. Set the maximum number of valid hole fits for  typed
1993              holes to display in type error messages.
1994
1995       -fno-show-valid-hole-fits
1996              Disables  showing  a  list of valid hole fits for typed holes in
1997              type error messages.
1998
1999       -fno-sort-valid-hole-fits
2000              Disables the sorting of the list of valid hole  fits  for  typed
2001              holes in type error messages.
2002
2003       -fprint-axiom-incomps
2004              Display equation incompatibilities in closed type families
2005
2006       -fprint-equality-relations
2007              Distinguish between equality relations when printing
2008
2009       -fprint-expanded-synonyms
2010              In type errors, also print type-synonym-expanded types.
2011
2012       -fprint-explicit-coercions
2013              Print coercions in types
2014
2015       -fprint-explicit-foralls
2016              Print explicit forall quantification in types.  See also Explic‐
2017              itForAll
2018
2019       -fprint-explicit-kinds
2020              Print explicit kind foralls and kind arguments  in  types.   See
2021              also KindSignatures
2022
2023       -fprint-explicit-runtime-reps
2024              Print  RuntimeRep variables in types which are runtime-represen‐
2025              tation polymorphic.
2026
2027       -fprint-potential-instances
2028              display all available instances in type error messages
2029
2030       -fprint-typechecker-elaboration
2031              Print extra information from typechecker.
2032
2033       -fprint-unicode-syntax
2034              Use unicode syntax when printing expressions, types  and  kinds.
2035              See also UnicodeSyntax
2036
2037       -frefinement-level-hole-fits=⟨n⟩
2038              default:  off.  Sets  the  level of refinement of the refinement
2039              hole fits, where level n means that hole fits of up to  n  holes
2040              will be considered.
2041
2042       -freverse-errors
2043              Output errors in reverse order
2044
2045       -fshow-docs-of-hole-fits
2046              Toggles whether to show the documentation of the valid hole fits
2047              in the output.
2048
2049       -fshow-hole-constraints
2050              Show constraints when reporting typed holes.
2051
2052       -fshow-hole-matches-of-hole-fits
2053              Toggles whether to show the type of the additional holes in  re‐
2054              finement hole fits.
2055
2056       -fshow-provenance-of-hole-fits
2057              Toggles whether to show the provenance of the valid hole fits in
2058              the output.
2059
2060       -fshow-type-app-of-hole-fits
2061              Toggles whether to show the type application of the  valid  hole
2062              fits in the output.
2063
2064       -fshow-type-app-vars-of-hole-fits
2065              Toggles whether to show what type each quantified variable takes
2066              in a valid hole fit.
2067
2068       -fshow-type-of-hole-fits
2069              Toggles whether to show the type of the valid hole fits  in  the
2070              output.
2071
2072       -funclutter-valid-hole-fits
2073              Unclutter  the list of valid hole fits by not showing provenance
2074              nor type applications of suggestions.
2075
2076       -Rghc-timing
2077              Summarise timing stats for GHC (same as +RTS -tstderr).
2078
2079       -v     verbose mode (equivalent to -v3)
2080
2081       -v⟨n⟩  set verbosity level
2082
2083   Warnings
2084       -fdefer-out-of-scope-variables
2085              Convert variable out of scope variables  errors  into  warnings.
2086              Implied     by     -fdefer-type-errors.     See    also    -Wde‐
2087              ferred-out-of-scope-variables.
2088
2089       -fdefer-type-errors
2090              Turn type errors into warnings, deferring the error  until  run‐
2091              time. Implies -fdefer-typed-holes and -fdefer-out-of-scope-vari‐
2092              ables.  See also -Wdeferred-type-errors
2093
2094       -fdefer-typed-holes
2095              Convert typed hole errors into warnings, deferring the error un‐
2096              til   runtime.    Implied   by  -fdefer-type-errors.   See  also
2097              -Wtyped-holes.
2098
2099       -fenable-th-splice-warnings
2100              Generate warnings for Template Haskell splices
2101
2102       -fhelpful-errors
2103              Make suggestions for mis-spelled names.
2104
2105       -fmax-pmcheck-models=⟨n⟩
2106              soft limit on the number of parallel models  the  pattern  match
2107              checker should check a pattern match clause against
2108
2109       -fshow-warning-groups
2110              show which group an emitted warning belongs to.
2111
2112       -fvia-C
2113              use the C code generator
2114
2115       -W     enable normal warnings
2116
2117       -w     disable all warnings
2118
2119       -Wall  enable almost all warnings (details in options-sanity)
2120
2121       -Wall-missed-specialisations
2122              warn when specialisation of any overloaded function fails.
2123
2124       -Wcompat
2125              enable future compatibility warnings (details in options-sanity)
2126
2127       -Wcompat-unqualified-imports
2128              Report  unqualified imports of core libraries which are expected
2129              to cause compatibility problems in future releases.
2130
2131       -Wcpp-undef
2132              warn on uses of the #if directive on undefined identifiers
2133
2134       -Wdeferred-out-of-scope-variables
2135              Report warnings when variable out-of-scope errors  are  deferred
2136              until runtime.  See -fdefer-out-of-scope-variables.
2137
2138       -Wdeferred-type-errors
2139              Report  warnings when deferred type errors are enabled. This op‐
2140              tion is enabled by default. See -fdefer-type-errors.
2141
2142       -Wdeprecated-flags
2143              warn about uses of commandline flags that are deprecated
2144
2145       -Wdeprecations
2146              warn about uses of functions & types that have warnings or  dep‐
2147              recated pragmas. Alias for -Wwarnings-deprecations
2148
2149       -Wderiving-defaults
2150              warn  about  default deriving when using both DeriveAnyClass and
2151              GeneralizedNewtypeDeriving
2152
2153       -Wdodgy-exports
2154              warn about dodgy exports
2155
2156       -Wdodgy-foreign-imports
2157              warn about dodgy foreign imports
2158
2159       -Wdodgy-imports
2160              warn about dodgy imports
2161
2162       -Wduplicate-constraints
2163              warn when a constraint appears duplicated in a type signature
2164
2165       -Wduplicate-exports
2166              warn when an entity is exported multiple times
2167
2168       -Wempty-enumerations
2169              warn about enumerations that are empty
2170
2171       -Werror
2172              make warnings fatal
2173
2174       -Weverything
2175              enable all warnings supported by GHC
2176
2177       -Whi-shadowing
2178              (deprecated) warn when a .hi file in the current directory shad‐
2179              ows a library
2180
2181       -Widentities
2182              warn about uses of Prelude numeric conversions that are probably
2183              the identity (and hence could be omitted)
2184
2185       -Wimplicit-kind-vars
2186              warn when kind variables are implicitly quantified over.
2187
2188       -Wimplicit-prelude
2189              warn when the Prelude is implicitly imported
2190
2191       -Winaccessible-code
2192              warn about inaccessible code
2193
2194       -Wincomplete-patterns
2195              warn when a pattern match could fail
2196
2197       -Wincomplete-record-updates
2198              warn when a record update could fail
2199
2200       -Wincomplete-uni-patterns
2201              warn when a pattern match in  a  lambda  expression  or  pattern
2202              binding could fail
2203
2204       -Winline-rule-shadowing
2205              Warn  if  a rewrite RULE might fail to fire because the function
2206              might be inlined before the rule has  a  chance  to  fire.   See
2207              rules-inline.
2208
2209       -Wmissed-extra-shared-lib
2210              Warn when GHCi can't load a shared lib.
2211
2212       -Wmissed-specialisations
2213              warn  when  specialisation  of  an imported, overloaded function
2214              fails.
2215
2216       -Wmissing-deriving-strategies
2217              warn when a deriving clause is missing a deriving strategy
2218
2219       -Wmissing-export-lists
2220              warn when a module declaration does not explicitly list all  ex‐
2221              ports
2222
2223       -Wmissing-exported-signatures
2224              warn  about top-level functions without signatures, only if they
2225              are exported. takes precedence over -Wmissing-signatures
2226
2227       -Wmissing-exported-sigs
2228              (deprecated) warn about top-level functions without  signatures,
2229              only  if they are exported. takes precedence over -Wmissing-sig‐
2230              natures
2231
2232       -Wmissing-fields
2233              warn when fields of a record are uninitialised
2234
2235       -Wmissing-home-modules
2236              warn when encountering a home module imported, but not listed on
2237              the  command  line. Useful for cabal to ensure GHC won't pick up
2238              modules,  not  listed  neither  in   exposed-modules,   nor   in
2239              other-modules.
2240
2241       -Wmissing-import-lists
2242              warn when an import declaration does not explicitly list all the
2243              names brought into scope
2244
2245       -Wmissing-local-signatures
2246              warn about polymorphic local bindings without signatures
2247
2248       -Wmissing-local-sigs
2249              (deprecated) warn about polymorphic local bindings without  sig‐
2250              natures
2251
2252       -Wmissing-methods
2253              warn when class methods are undefined
2254
2255       -Wmissing-monadfail-instances
2256              Warn when a failable pattern is used in a do-block that does not
2257              have a MonadFail instance.
2258
2259       -Wmissing-pattern-synonym-signatures
2260              warn when pattern synonyms do not have type signatures
2261
2262       -Wmissing-signatures
2263              warn about top-level functions without signatures
2264
2265       -Wmonomorphism-restriction
2266              warn when the Monomorphism Restriction is applied
2267
2268       -Wname-shadowing
2269              warn when names are shadowed
2270
2271       -Wno-compat
2272              Disables all warnings enabled by -Wcompat.
2273
2274       -Wnoncanonical-monad-instances
2275              warn when Applicative or Monad instances have noncanonical defi‐
2276              nitions of return, pure, (>>), or (*>).  See flag description in
2277              options-sanity for more details.
2278
2279       -Wnoncanonical-monadfail-instances
2280              warn when Monad or MonadFail instances have noncanonical defini‐
2281              tions  of fail.  See flag description in options-sanity for more
2282              details.
2283
2284       -Wnoncanonical-monoid-instances
2285              warn when Semigroup or Monoid instances have noncanonical  defi‐
2286              nitions  of  (<>)  or  mappend.   See  flag  description  in op‐
2287              tions-sanity for more details.
2288
2289       -Worphans
2290              warn when the module contains orphan  instance  declarations  or
2291              rewrite rules
2292
2293       -Woverflowed-literals
2294              warn about literals that will overflow their type
2295
2296       -Woverlapping-patterns
2297              warn about overlapping patterns
2298
2299       -Wpartial-fields
2300              warn when defining a partial record field.
2301
2302       -Wpartial-type-signatures
2303              warn about holes in partial type signatures when PartialTypeSig‐
2304              natures is enabled. Not applicable when PartialTypeSignatures is
2305              not enabled, in which case errors are generated for such holes.
2306
2307       -Wredundant-constraints
2308              Have  the compiler warn about redundant constraints in type sig‐
2309              natures.
2310
2311       -Wredundant-record-wildcards
2312              Warn about record wildcard matches when the  wildcard  binds  no
2313              patterns.
2314
2315       -Wsafe warn if the module being compiled is regarded to be safe.
2316
2317       -Wsemigroup
2318              warn when a Monoid is not Semigroup, and on non- Semigroup defi‐
2319              nitions of (<>)?
2320
2321       -Wsimplifiable-class-constraints
2322              Warn about class constraints in a type  signature  that  can  be
2323              simplified using a top-level instance declaration.
2324
2325       -Wspace-after-bang
2326              warn  for  missing  space before the second argument of an infix
2327              definition of (!) when BangPatterns are not enabled
2328
2329       -Wstar-binder
2330              warn about binding the (*) type operator despite StarIsType
2331
2332       -Wstar-is-type
2333              warn when * is used to mean Data.Kind.Type
2334
2335       -Wtabs warn if there are tabs in the source file
2336
2337       -Wtrustworthy-safe
2338              warn if the module being compiled is marked as  Trustworthy  but
2339              it could instead be marked as Safe, a more informative bound.
2340
2341       -Wtype-defaults
2342              warn when defaulting happens
2343
2344       -Wtyped-holes
2345              Report  warnings  when typed hole errors are deferred until run‐
2346              time. See -fdefer-typed-holes.
2347
2348       -Wunbanged-strict-patterns
2349              warn on pattern bind of unlifted variable that is  neither  bare
2350              nor banged
2351
2352       -Wunrecognised-pragmas
2353              warn about uses of pragmas that GHC doesn't recognise
2354
2355       -Wunrecognised-warning-flags
2356              throw  a  warning when an unrecognised -W... flag is encountered
2357              on the command line.
2358
2359       -Wunsafe
2360              warn if the module being compiled is regarded to be unsafe.  See
2361              safe-haskell
2362
2363       -Wunsupported-calling-conventions
2364              warn about use of an unsupported calling convention
2365
2366       -Wunsupported-llvm-version
2367              Warn when using -fllvm with an unsupported version of LLVM.
2368
2369       -Wunticked-promoted-constructors
2370              warn if promoted constructors are not ticked
2371
2372       -Wunused-binds
2373              warn    about    bindings    that    are   unused.   Alias   for
2374              -Wunused-top-binds,   -Wunused-local-binds   and   -Wunused-pat‐
2375              tern-binds
2376
2377       -Wunused-do-bind
2378              warn about do bindings that appear to throw away values of types
2379              other than ()
2380
2381       -Wunused-foralls
2382              warn about type variables in user-written forall\s that are  un‐
2383              used
2384
2385       -Wunused-imports
2386              warn about unnecessary imports
2387
2388       -Wunused-local-binds
2389              warn about local bindings that are unused
2390
2391       -Wunused-matches
2392              warn about variables in patterns that aren't used
2393
2394       -Wunused-packages
2395              warn  when  package  is requested on command line, but was never
2396              loaded.
2397
2398       -Wunused-pattern-binds
2399              warn about pattern match bindings that are unused
2400
2401       -Wunused-record-wildcards
2402              Warn about record wildcard matches when none of the bound  vari‐
2403              ables are used.
2404
2405       -Wunused-top-binds
2406              warn about top-level bindings that are unused
2407
2408       -Wunused-type-patterns
2409              warn about unused type variables which arise from patterns in in
2410              type family and data family instances
2411
2412       -Wwarn make warnings non-fatal
2413
2414       -Wwarnings-deprecations
2415              warn about uses of functions & types that have warnings or  dep‐
2416              recated pragmas
2417
2418       -Wwrong-do-bind
2419              warn  about do bindings that appear to throw away monadic values
2420              that you should have bound instead
2421
2423       Copyright 2015. The University Court of the University of Glasgow.  All
2424       rights reserved.
2425

AUTHOR

2427       The GHC Team
2428
2430       2022, GHC Team
2431
2432
2433
2434
24358.10.5                           Jan 20, 2022                           GHC(1)
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