1GHC(1) Glasgow Haskell Compiler GHC(1)
2
6 ghc - the Glasgow Haskell Compiler
7
9 ghc [option|filename]
10 ghci [option|filename]
11
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 <https://down‐
16 loads.haskell.org/ghc/latest/docs/users_guide.pdf> and HTML
17 <https://downloads.haskell.org/ghc/latest/docs/html/>.
18 Each of GHC's command line options is classified as either static or
20 dynamic. A static flag may only be specified on the command line,
21 whereas a dynamic flag may also be given in an OPTIONS pragma in a
22 source file or set from the GHCi command-line with :set .
23 As a rule of thumb, all the language options are dynamic, as are the
25 warning options and the debugging options.
26 The rest are static, with the notable exceptions of -v, -cpp, -fasm,
28 -fvia-C, -fllvm, and -#include. The OPTIONS sections lists the status
29 of each flag.
30 Common suffixes of file names for Haskell are:
32 .hs Haskell source code; preprocess, compile
34 .lhs literate Haskell source; unlit, preprocess, compile
36 .hi Interface file; contains information about exported symbols
38 .hc intermediate C files
40 .⟨way⟩_o
42 object files for "way" ⟨way⟩; common ways are:
43 dyn dynamically-linked
45 p built with profiling
47 .⟨way⟩_hi
49 interface files for "way" ⟨way⟩; common ways are:
50
52 Code generation
53 -dynamic-too -fasm -fllvm -fbyte-code -fexpose-internal-symbols
54 -fexternal-dynamic-refs -fllvm -fasm -fno-code -fobject-code
55 -fPIC -fPIE -fwrite-interface -split-objs
56 Debugging the compiler
58 -dasm-lint -dcmm-lint -dcore-lint -ddump-asm -ddump-asm-con‐
59 flicts -ddump-asm-liveness -ddump-asm-native -ddump-asm-regalloc
60 -ddump-asm-regalloc-stages -ddump-asm-stats -ddump-bcos
61 -ddump-c-backend -ddump-call-arity -ddump-cfg-weights -ddump-cmm
62 -ddump-cmm-caf -ddump-cmm-cbe -ddump-cmm-cfg -ddump-cmm-cps
63 -ddump-cmm-from-stg -ddump-cmm-info -ddump-cmm-opt
64 -ddump-cmm-proc -ddump-cmm-procmap -ddump-cmm-raw
65 -ddump-cmm-sink -ddump-cmm-sp -ddump-cmm-split -ddump-cmm-switch
66 -ddump-cmm-verbose -ddump-cmm-verbose-by-proc -ddump-core-stats
67 -ddump-cpr-signatures -ddump-cpranal -ddump-cs-trace -ddump-cse
68 -ddump-debug -ddump-deriv -ddump-ds -ddump-ds-preopt
69 -ddump-ec-trace -ddump-exitify -ddump-faststrings
70 -ddump-file-prefix=⟨str⟩ -ddump-foreign -ddump-hie -ddump-hpc
71 -ddump-if-trace -ddump-inlinings -ddump-json -ddump-late-cc
72 -ddump-llvm -ddump-mod-map -ddump-occur-anal -ddump-opt-cmm
73 -ddump-parsed -ddump-parsed-ast -ddump-prep -ddump-rn
74 -ddump-rn-ast -ddump-rn-stats -ddump-rn-trace -ddump-rtti
75 -ddump-rule-firings -ddump-rule-rewrites -ddump-rules
76 -ddump-simpl -ddump-simpl-iterations -ddump-simpl-stats
77 -ddump-simpl-trace -ddump-spec -ddump-splices -ddump-stg
78 -ddump-stg-cg -ddump-stg-final -ddump-stg-from-core
79 -ddump-stg-tags -ddump-stg-unarised -ddump-str-signatures
80 -ddump-stranal -ddump-tc -ddump-tc-ast -ddump-tc-trace
81 -ddump-ticked -ddump-timings -ddump-to-file -ddump-types
82 -ddump-verbose-inlinings -ddump-view-pattern-commoning
83 -ddump-worker-wrapper -dfaststring-stats -dhex-word-literals
84 -dinitial-unique=⟨s⟩ -dinline-check=⟨str⟩ -dkeep-comments -dlin‐
85 ear-core-lint -dlint -dno-debug-output -ddebug-output -dno-ty‐
86 peable-binds -dppr-case-as-let -dppr-cols=⟨n⟩ -dppr-debug
87 -dppr-user-length -drule-check=⟨str⟩ -dshow-passes -dstg-lint
88 -dsuppress-all -dsuppress-coercion-types -dsuppress-coercions
89 -dsuppress-core-sizes -dsuppress-idinfo -dsuppress-module-pre‐
90 fixes -dsuppress-stg-free-vars -dsuppress-stg-reps -dsup‐
91 press-ticks -dsuppress-timestamps -dsuppress-type-applications
92 -dsuppress-type-signatures -dsuppress-unfoldings -dsup‐
93 press-uniques -dsuppress-var-kinds -dtag-inference-checks
94 -dth-dec-file -dunique-increment=⟨i⟩ -dverbose-core2core -dver‐
95 bose-stg2stg -falignment-sanitisation -fcatch-nonexhaus‐
96 tive-cases -fcheck-prim-bounds -fdistinct-constructor-tables
97 -finfo-table-map -fllvm-fill-undef-with-garbage -fproc-alignment
98 -g -g⟨n⟩
99 C pre-processor
101 -cpp -D⟨symbol⟩[=⟨value⟩] -U⟨symbol⟩ -I⟨dir⟩ -U⟨symbol⟩
102 Finding imports
104 -i -i⟨dir⟩[:⟨dir⟩]*
105 Interactive mode
107 -fbreak-on-error -fno-break-on-error -fbreak-on-exception
108 -fno-break-on-exception -fghci-hist-size=⟨n⟩ -fghci-leak-check
109 -fno-ghci-leak-check -fimplicit-import-qualified -fno-im‐
110 plicit-import-qualified -flocal-ghci-history -fno-lo‐
111 cal-ghci-history -fno-it -fno-no-it -fprint-bind-result
112 -fno-print-bind-result -fprint-evld-with-show -fshow-loaded-mod‐
113 ules -ghci-script -ignore-dot-ghci -no-ignore-dot-ghci -interac‐
114 tive-print ⟨name⟩
115 Interface files
117 --show-iface ⟨file⟩ -ddump-hi -ddump-hi-diffs -ddump-minimal-im‐
118 ports
119 Keeping intermediate files
121 -keep-hc-file -keep-hc-files -keep-hi-files -no-keep-hi-files
122 -keep-hscpp-file -keep-hscpp-files -keep-llvm-file
123 -keep-llvm-files -keep-o-files -no-keep-o-files -keep-s-file
124 -keep-s-files -keep-tmp-files
125 Language options
127 -XAllowAmbiguousTypes -XApplicativeDo -XArrows -XBangPatterns
128 -XBinaryLiterals -XBlockArguments -XCApiFFI -XConstrainedClass‐
129 Methods -XConstraintKinds -XCPP -XCUSKs -XDataKinds -XDatatype‐
130 Contexts -XDeepSubsumption -XDefaultSignatures -XDeriveAnyClass
131 -XDeriveDataTypeable -XDeriveFoldable -XDeriveFunctor -XDeriveG‐
132 eneric -XDeriveLift -XDeriveTraversable -XDerivingStrategies
133 -XDerivingVia -XDisambiguateRecordFields -XDuplicateRecordFields
134 -XEmptyCase -XEmptyDataDecls -XEmptyDataDeriving -XExisten‐
135 tialQuantification -XExplicitForAll -XExplicitNamespaces -XEx‐
136 tendedDefaultRules -XFieldSelectors -XFlexibleContexts -XFlexi‐
137 bleInstances -XForeignFunctionInterface -XFunctionalDependencies
138 -XGADTs -XGADTSyntax -XGeneralisedNewtypeDeriving -XGeneralized‐
139 NewtypeDeriving -XGHC2021 -XGHCForeignImportPrim -XHaskell2010
140 -XHaskell98 -XHexFloatLiterals -XImplicitParams -XImportQuali‐
141 fiedPost -XImpredicativeTypes -XIncoherentInstances -XInstance‐
142 Sigs -XInterruptibleFFI -XKindSignatures -XLambdaCase -XLexical‐
143 Negation -XLiberalTypeSynonyms -XLinearTypes -XMagicHash -XMon‐
144 adComprehensions -XMonoLocalBinds -XMultiParamTypeClasses -XMul‐
145 tiWayIf -XNamedFieldPuns -XNamedWildCards -XNegativeLiterals
146 -XNoImplicitPrelude -XNoMonomorphismRestriction -XNonde‐
147 creasingIndentation -XNoPatternGuards -XNoTraditionalRecordSyn‐
148 tax -XNPlusKPatterns -XNullaryTypeClasses -XNumDecimals -XNumer‐
149 icUnderscores -XOverlappingInstances -XOverloadedLabels -XOver‐
150 loadedLists -XOverloadedRecordDot -XOverloadedRecordUpdate
151 -XOverloadedStrings -XPackageImports -XParallelListComp -XPar‐
152 tialTypeSignatures -XPatternSynonyms -XPolyKinds -XPostfixOpera‐
153 tors -XQualifiedDo -XQuantifiedConstraints -XQuasiQuotes
154 -XRank2Types -XRankNTypes -XRebindableSyntax -XRecordWildCards
155 -XRecursiveDo -XRoleAnnotations -XSafe -XScopedTypeVariables
156 -XStandaloneDeriving -XStandaloneKindSignatures -XStarIsType
157 -XStaticPointers -XStrict -XStrictData -XTemplateHaskell -XTem‐
158 plateHaskellQuotes -XTransformListComp -XTrustworthy -XTupleSec‐
159 tions -XTypeApplications -XTypeFamilies -XTypeFamilyDependencies
160 -XTypeInType -XTypeOperators -XTypeSynonymInstances -XUnboxed‐
161 Sums -XUnboxedTuples -XUndecidableInstances -XUndecidableSuper‐
162 Classes -XUnicodeSyntax -XUnliftedDatatypes -XUnliftedFFITypes
163 -XUnliftedNewtypes -XUnsafe -XViewPatterns
164 Linking options
166 -c -debug -dylib-install-name ⟨path⟩ -dynamic -dynload -eventlog
167 -fcompact-unwind -fkeep-cafs -flink-rts -fno-embed-manifest
168 -fno-gen-manifest -fno-shared-implib -framework ⟨name⟩ -frame‐
169 work-path ⟨dir⟩ -fuse-rpaths -fwhole-archive-hs-libs -L ⟨dir⟩ -l
170 ⟨lib⟩ -main-is ⟨thing⟩ -no-hs-main -no-link -no-pie -pie -no-rt‐
171 sopts-suggestions -package ⟨name⟩ -pie -no-pie -rdynamic -rt‐
172 sopts[=⟨none|some|all|ignore|ignoreAll⟩] -shared -split-sections
173 -static -staticlib -threaded -with-rtsopts=⟨opts⟩
174 Miscellaneous options
176 -fexternal-interpreter -ffamily-application-cache -fno-fam‐
177 ily-application-cache -fglasgow-exts -fno-glasgow-exts
178 -fno-safe-haskell -ghcversion-file ⟨path to ghcversion.h⟩ -H
179 ⟨size⟩ -hidden-module ⟨module name⟩ -j[⟨n⟩] -reexported-module
180 ⟨module name⟩ -this-package-name ⟨unit-id⟩ -unit @⟨filename⟩
181 -working-dir ⟨dir⟩
182 Modes of operation
184 --frontend ⟨module⟩ --help -? --info --interactive --make --nu‐
185 meric-version --print-booter-version --print-build-platform
186 --print-c-compiler-flags --print-c-compiler-link-flags
187 --print-debug-on --print-global-package-db --print-have-inter‐
188 preter --print-have-native-code-generator --print-host-platform
189 --print-ld-flags --print-leading-underscore --print-libdir
190 --print-object-splitting-supported --print-project-git-commit-id
191 --print-project-version --print-rts-ways --print-stage
192 --print-support-smp --print-tables-next-to-code --print-tar‐
193 get-platform --print-unregisterised --run ⟨file⟩ --show-iface
194 ⟨file⟩ --show-options --supported-extensions --supported-lan‐
195 guages --version -V -e ⟨expr⟩ -M -shared
196 Individual optimizations
198 -fasm-shortcutting -fno-asm-shortcutting -fbinary-blob-thresh‐
199 old=⟨n⟩ -fblock-layout-cfg -fno-block-layout-cfg -fblock-lay‐
200 out-weightless -fno-block-layout-weightless -fblock-lay‐
201 out-weights -fcall-arity -fno-call-arity -fcase-folding
202 -fno-case-folding -fcase-merge -fno-case-merge -fcmm-con‐
203 trol-flow -fno-cmm-control-flow -fcmm-elim-common-blocks
204 -fno-cmm-elim-common-blocks -fcmm-sink -fno-cmm-sink
205 -fcmm-static-pred -fno-cmm-static-pred -fcore-constant-folding
206 -fno-core-constant-folding -fcpr-anal -fno-cpr-anal -fcross-mod‐
207 ule-specialise -fno-cross-module-specialise -fcse -fno-cse
208 -fdicts-cheap -fno-dicts-cheap -fdicts-strict -fno-dicts-strict
209 -fdmd-tx-dict-sel -fno-dmd-tx-dict-sel -fdmd-unbox-width=⟨n⟩
210 -fdo-eta-reduction -fno-do-eta-reduction -fdo-lambda-eta-expan‐
211 sion -fno-do-lambda-eta-expansion -feager-blackholing -fen‐
212 able-rewrite-rules -fno-enable-rewrite-rules -fexcess-precision
213 -fno-excess-precision -fexitification -fno-exitification -fex‐
214 pose-all-unfoldings -fno-expose-all-unfoldings -ffloat-in
215 -fno-float-in -ffull-laziness -fno-full-laziness -ffun-to-thunk
216 -fno-fun-to-thunk -fignore-asserts -fno-ignore-asserts -fig‐
217 nore-interface-pragmas -fno-ignore-interface-pragmas -fin‐
218 line-generics -fno-inline-generics -finline-generics-aggres‐
219 sively -fno-inline-generics-aggressively -flate-dmd-anal
220 -fno-late-dmd-anal -flate-specialise -fno-late-specialise -flib‐
221 erate-case -fno-liberate-case -fliberate-case-threshold=⟨n⟩
222 -fno-liberate-case-threshold -fllvm-pass-vectors-in-regs -floop‐
223 ification -fno-loopification -fmax-inline-alloc-size=⟨n⟩
224 -fmax-inline-memcpy-insns=⟨n⟩ -fmax-inline-memset-insns=⟨n⟩
225 -fmax-simplifier-iterations=⟨n⟩ -fmax-uncovered-patterns=⟨n⟩
226 -fmax-worker-args=⟨n⟩ -fno-opt-coercion -fno-pre-inlining
227 -fno-state-hack -fomit-interface-pragmas -fno-omit-inter‐
228 face-pragmas -fomit-yields -fno-omit-yields -foptimal-applica‐
229 tive-do -fno-optimal-applicative-do -fpedantic-bottoms
230 -fno-pedantic-bottoms -fregs-graph -fno-regs-graph -fregs-itera‐
231 tive -fno-regs-iterative -fsimpl-tick-factor=⟨n⟩ -fsimpli‐
232 fier-phases=⟨n⟩ -fsolve-constant-dicts -fno-solve-constant-dicts
233 -fspec-constr -fno-spec-constr -fspec-constr-count=⟨n⟩
234 -fno-spec-constr-count -fspec-constr-keen -fno-spec-constr-keen
235 -fspec-constr-threshold=⟨n⟩ -fno-spec-constr-threshold -fspe‐
236 cialise -fno-specialise -fspecialise-aggressively -fno-spe‐
237 cialise-aggressively -fstatic-argument-transformation
238 -fno-static-argument-transformation -fstg-cse -fno-stg-cse
239 -fstg-lift-lams -fno-stg-lift-lams -fstg-lift-lams-known
240 -fno-stg-lift-lams-known -fstg-lift-lams-non-rec-args
241 -fstg-lift-lams-non-rec-args-any -fstg-lift-lams-rec-args
242 -fstg-lift-lams-rec-args-any -fstrictness -fno-strictness
243 -fstrictness-before=⟨n⟩ -funbox-small-strict-fields -fno-un‐
244 box-small-strict-fields -funbox-strict-fields -fno-un‐
245 box-strict-fields -funfolding-case-scaling=⟨n⟩ -funfold‐
246 ing-case-threshold=⟨n⟩ -funfolding-creation-threshold=⟨n⟩ -fun‐
247 folding-dict-discount=⟨n⟩ -funfolding-fun-discount=⟨n⟩ -funfold‐
248 ing-keeness-factor=⟨n⟩ -funfolding-use-threshold=⟨n⟩
249 -fworker-wrapper -fworker-wrapper-cbv
250 Optimization levels
252 -O -O1 -O0 -O0 -O2 -O0 -O⟨n⟩ -O0
253 Package options
255 -clear-package-db -distrust ⟨pkg⟩ -distrust-all-packages -fpack‐
256 age-trust -global-package-db -hide-all-packages -hide-package
257 ⟨pkg⟩ -ignore-package ⟨pkg⟩ -no-auto-link-packages
258 -no-global-package-db -no-user-package-db -package ⟨pkg⟩ -pack‐
259 age-db ⟨file⟩ -package-env ⟨file⟩|⟨name⟩ -package-id ⟨unit-id⟩
260 -this-unit-id ⟨unit-id⟩ -trust ⟨pkg⟩ -user-package-db
261 Phases of compilation
263 --merge-objs -C -c -E -F -S -x ⟨suffix⟩
264 Overriding external programs
266 -pgma ⟨cmd⟩ -pgmc ⟨cmd⟩ -pgmcxx ⟨cmd⟩ -pgmdll ⟨cmd⟩ -pgmF ⟨cmd⟩
267 -pgmi ⟨cmd⟩ -pgminstall_name_tool ⟨cmd⟩ -pgmL ⟨cmd⟩ -pgml ⟨cmd⟩
268 -pgmlc ⟨cmd⟩ -pgmlibtool ⟨cmd⟩ -pgmlm ⟨cmd⟩ -pgmlo ⟨cmd⟩ -pgmo‐
269 tool ⟨cmd⟩ -pgmP ⟨cmd⟩ -pgms ⟨cmd⟩ -pgmwindres ⟨cmd⟩
270 Phase-specific options
272 -opta ⟨option⟩ -optc ⟨option⟩ -optcxx ⟨option⟩ -optdll ⟨option⟩
273 -optF ⟨option⟩ -opti ⟨option⟩ -optL ⟨option⟩ -optl ⟨option⟩
274 -optlc ⟨option⟩ -optlm ⟨option⟩ -optlo ⟨option⟩ -optP ⟨option⟩
275 -optwindres ⟨option⟩ -pgmc-supports-no-pie -pgml-supports-no-pie
276 Platform-specific options
278 -mavx -mavx2 -mavx512cd -mavx512er -mavx512f -mavx512pf -mbmi
279 -mbmi2 -msse -msse2 -msse3 -msse4 -msse4.2
280 Compiler plugins
282 -fclear-plugins -fplugin-opt=⟨module⟩:⟨args⟩ -fplugin-trustwor‐
283 thy -fplugin=⟨module⟩ -hide-all-plugin-packages -plugin-package
284 ⟨pkg⟩ -plugin-package-id ⟨pkg-id⟩
285 Profiling
287 -auto -auto-all -caf-all -fno-prof-count-entries
288 -fprof-count-entries -fprof-auto -fno-prof-auto
289 -fprof-auto-calls -fno-prof-auto -fprof-auto-exported
290 -fno-prof-auto -fprof-auto-top -fno-prof-auto -fprof-cafs
291 -fno-prof-cafs -fprof-callers=⟨name⟩ -fprof-late -fno-prof-late
292 -fprof-late-inline -fno-prof-late-inline -fprof-manual
293 -fno-prof-manual -no-auto -no-auto-all -no-caf-all -prof -ticky
294 -ticky-allocd -ticky-ap-thunk -ticky-dyn-thunk -ticky-LNE
295 -ticky-tag-checks
296 Program coverage
298 -fhpc -hpcdir⟨dir⟩
299 Recompilation checking
301 -fforce-recomp -fno-force-recomp -fignore-hpc-changes -fno-ig‐
302 nore-hpc-changes -fignore-optim-changes -fno-ignore-op‐
303 tim-changes
304 Redirecting output
306 --exclude-module=⟨file⟩ -ddump-mod-cycles -dep-makefile ⟨file⟩
307 -dep-suffix ⟨suffix⟩ -dumpdir ⟨dir⟩ -dynhisuf ⟨suffix⟩ -dyno
308 ⟨file⟩ -dynohi ⟨file⟩ -dynosuf ⟨suffix⟩ -hcsuf ⟨suffix⟩ -hidir
309 ⟨dir⟩ -hiedir ⟨dir⟩ -hiesuf ⟨suffix⟩ -hisuf ⟨suffix⟩ -in‐
310 clude-cpp-deps -include-pkg-deps -o ⟨file⟩ -odir ⟨dir⟩ -ohi
311 ⟨file⟩ -osuf ⟨suffix⟩ -outputdir ⟨dir⟩ -stubdir ⟨dir⟩
312 Temporary files
314 -tmpdir ⟨dir⟩
315 Verbosity options
317 -fabstract-refinement-hole-fits -fno-abstract-refine‐
318 ment-hole-fits -fdefer-diagnostics -fdiagnostics-color=⟨al‐
319 ways|auto|never⟩ -fdiagnostics-show-caret -fno-diagnos‐
320 tics-show-caret -ferror-spans -fhide-source-paths -fkeep-going
321 -fmax-refinement-hole-fits=⟨n⟩ -fno-max-refinement-hole-fits
322 -fmax-relevant-binds=⟨n⟩ -fno-max-relevant-binds
323 -fmax-valid-hole-fits=⟨n⟩ -fno-max-valid-hole-fits
324 -fno-show-valid-hole-fits -fno-sort-valid-hole-fits
325 -fsort-valid-hole-fits -fprint-axiom-incomps -fno-print-ax‐
326 iom-incomps -fprint-equality-relations -fno-print-equality-rela‐
327 tions -fprint-expanded-synonyms -fno-print-expanded-synonyms
328 -fprint-explicit-coercions -fno-print-explicit-coercions
329 -fprint-explicit-foralls -fno-print-explicit-foralls -fprint-ex‐
330 plicit-kinds -fno-print-explicit-kinds -fprint-explicit-run‐
331 time-reps -fno-print-explicit-runtime-reps -fprint-potential-in‐
332 stances -fno-print-potential-instances -fprint-typechecker-elab‐
333 oration -fno-print-typechecker-elaboration -fprint-unicode-syn‐
334 tax -fno-print-unicode-syntax -frefinement-level-hole-fits=⟨n⟩
335 -fno-refinement-level-hole-fits -freverse-errors -fno-re‐
336 verse-errors -fshow-docs-of-hole-fits
337 -fno-show-docs-of-hole-fits -fshow-hole-constraints
338 -fshow-hole-matches-of-hole-fits
339 -fno-show-hole-matches-of-hole-fits -fshow-prove‐
340 nance-of-hole-fits -fno-show-provenance-of-hole-fits
341 -fshow-type-app-of-hole-fits -fno-show-type-app-of-hole-fits
342 -fshow-type-app-vars-of-hole-fits
343 -fno-show-type-app-vars-of-hole-fits -fshow-type-of-hole-fits
344 -fno-show-type-of-hole-fits -fsort-by-size-hole-fits
345 -fno-sort-by-size-hole-fits -fsort-by-subsumption-hole-fits
346 -fno-sort-by-subsumption-hole-fits -funclutter-valid-hole-fits
347 -Rghc-timing -v -v⟨n⟩
348 Warnings
350 -fdefer-out-of-scope-variables -fno-defer-out-of-scope-variables
351 -fdefer-type-errors -fno-defer-type-errors -fdefer-typed-holes
352 -fno-defer-typed-holes -fenable-th-splice-warnings -fno-en‐
353 able-th-splice-warnings -fhelpful-errors -fno-helpful-errors
354 -fmax-pmcheck-models=⟨n⟩ -fshow-warning-groups -fno-show-warn‐
355 ing-groups -fvia-C -W -w -w -Wall -w -Wall-missed-specialisa‐
356 tions -Wno-all-missed-specialisations -Wall-missed-specializa‐
357 tions -Wno-all-missed-specializations -Wambiguous-fields
358 -Wauto-orphans -Wcompat -Wno-compat -Wcompat-unqualified-imports
359 -Wno-compat-unqualified-imports -Wcpp-undef -Wdefault -Wde‐
360 ferred-out-of-scope-variables -Wno-deferred-out-of-scope-vari‐
361 ables -Wdeferred-type-errors -Wno-deferred-type-errors -Wdepre‐
362 cated-flags -Wno-deprecated-flags -Wdeprecations -Wno-depreca‐
363 tions -Wderiving-defaults -Wno-deriving-defaults -Wderiving-ty‐
364 peable -Wno-deriving-typeable -Wdodgy-exports -Wno-dodgy-exports
365 -Wdodgy-foreign-imports -Wno-dodgy-foreign-imports -Wdodgy-im‐
366 ports -Wno-dodgy-imports -Wduplicate-constraints -Wno-dupli‐
367 cate-constraints -Wduplicate-exports -Wno-duplicate-exports
368 -Wempty-enumerations -Wno-empty-enumerations -Werror -Wwarn
369 -Weverything -Wextra -w -Wforall-identifier -Wno-forall-identi‐
370 fier -Wgadt-mono-local-binds -Wno-gadt-mono-local-binds
371 -Whi-shadowing -Wno-hi-shadowing -Widentities -Wno-identities
372 -Wimplicit-kind-vars -Wno-implicit-kind-vars -Wimplicit-lift
373 -Wno-implicit-lift -Wimplicit-prelude -Wno-implicit-prelude
374 -Winaccessible-code -Wno-inaccessible-code -Wincomplete-patterns
375 -Wno-incomplete-patterns -Wincomplete-record-updates -Wno-incom‐
376 plete-record-updates -Wincomplete-uni-patterns -Wno-incom‐
377 plete-uni-patterns -Winferred-safe-imports -Wno-in‐
378 ferred-safe-imports -Winline-rule-shadowing -Wno-in‐
379 line-rule-shadowing -Winvalid-haddock -Wno-invalid-haddock
380 -Wmisplaced-pragmas -Wno-misplaced-pragmas -Wmissed-ex‐
381 tra-shared-lib -Wno-missed-extra-shared-lib -Wmissed-specialisa‐
382 tions -Wno-missed-specialisations -Wmissed-specializations
383 -Wno-missed-specializations -Wmissing-deriving-strategies
384 -Wno-missing-deriving-strategies -Wmissing-export-lists
385 -Wno-missing-export-lists -Wmissing-exported-pattern-syn‐
386 onym-signatures -Wno-missing-exported-pattern-synonym-signatures
387 -Wmissing-exported-signatures -Wno-missing-exported-signatures
388 -Wmissing-exported-sigs -Wno-missing-exported-sigs -Wmiss‐
389 ing-fields -Wno-missing-fields -Wmissing-home-modules -Wno-miss‐
390 ing-home-modules -Wmissing-import-lists -Wno-missing-im‐
391 port-lists -Wmissing-kind-signatures -Wno-missing-kind-signa‐
392 tures -Wmissing-local-signatures -Wno-missing-local-signatures
393 -Wmissing-local-sigs -Wno-missing-local-sigs -Wmissing-methods
394 -Wno-missing-methods -Wmissing-monadfail-instances -Wno-miss‐
395 ing-monadfail-instances -Wmissing-pattern-synonym-signatures
396 -Wno-missing-pattern-synonym-signatures -Wmiss‐
397 ing-safe-haskell-mode -Wno-missing-safe-haskell-mode -Wmiss‐
398 ing-signatures -Wno-missing-signatures -Wmissing-space-af‐
399 ter-bang -Wmonomorphism-restriction -Wno-monomorphism-restric‐
400 tion -Wname-shadowing -Wno-name-shadowing -Wno-compat -Wcompat
401 -Wnoncanonical-monad-instances -Wno-noncanonical-monad-instances
402 -Wnoncanonical-monadfail-instances -Wno-noncanonical-monad‐
403 fail-instances -Wnoncanonical-monoid-instances -Wno-noncanoni‐
404 cal-monoid-instances -Wnot -Woperator-whitespace -Wno-opera‐
405 tor-whitespace -Woperator-whitespace-ext-conflict -Wno-opera‐
406 tor-whitespace-ext-conflict -Worphans -Wno-orphans -Wover‐
407 flowed-literals -Wno-overflowed-literals -Woverlapping-patterns
408 -Wno-overlapping-patterns -Wpartial-fields -Wno-partial-fields
409 -Wpartial-type-signatures -Wno-partial-type-signatures -Wprepos‐
410 itive-qualified-module -Wno-prepositive-qualified-module -Wre‐
411 dundant-bang-patterns -Wno-redundant-bang-patterns -Wredun‐
412 dant-constraints -Wno-redundant-constraints -Wredun‐
413 dant-record-wildcards -Wno-redundant-record-wildcards -Wredun‐
414 dant-strictness-flags -Wno-redundant-strictness-flags -Wsafe
415 -Wno-safe -Wsemigroup -Wno-semigroup -Wsimplifiable-class-con‐
416 straints -Wno-simplifiable-class-constraints -Wstar-binder
417 -Wno-star-binder -Wstar-is-type -Wno-star-is-type -Wtabs
418 -Wno-tabs -Wtrustworthy-safe -Wno-safe -Wtype-defaults
419 -Wno-type-defaults -Wtype-equality-out-of-scope -Wno-type-equal‐
420 ity-out-of-scope -Wtype-equality-requires-operators
421 -Wno-type-equality-requires-operators -Wtyped-holes
422 -Wno-typed-holes -Wunbanged-strict-patterns -Wno-un‐
423 banged-strict-patterns -Wunicode-bidirectional-format-characters
424 -Wunrecognised-pragmas -Wno-unrecognised-pragmas -Wunrecog‐
425 nised-warning-flags -Wno-unrecognised-warning-flags -Wunsafe
426 -Wno-unsafe -Wunsupported-calling-conventions -Wno-unsup‐
427 ported-calling-conventions -Wunsupported-llvm-version
428 -Wno-monomorphism-restriction -Wunticked-promoted-constructors
429 -Wno-unticked-promoted-constructors -Wunused-binds -Wno-un‐
430 used-binds -Wunused-do-bind -Wno-unused-do-bind -Wunused-foralls
431 -Wno-unused-foralls -Wunused-imports -Wno-unused-imports
432 -Wunused-local-binds -Wno-unused-local-binds -Wunused-matches
433 -Wno-unused-matches -Wunused-packages -Wno-unused-packages
434 -Wunused-pattern-binds -Wno-unused-pattern-binds
435 -Wunused-record-wildcards -Wno-unused-record-wildcards
436 -Wunused-top-binds -Wno-unused-top-binds -Wunused-type-patterns
437 -Wno-unused-type-patterns -Wwarn -Werror -Wwarnings-deprecations
438 -Wno-warnings-deprecations -Wwrong-do-bind -Wno-wrong-do-bind
439 Code generation
441 -dynamic-too
442 Build dynamic object files as well as static object files during
443 compilation
444 -fasm Use the native code generator
446 -fbyte-code
448 Generate byte-code
449 -fexpose-internal-symbols
451 Produce symbols for all functions, including internal functions.
452 -fexternal-dynamic-refs
454 Generate code for linking against dynamic libraries
455 -fllvm Compile using the LLVM code generator
457 -fno-code
459 Omit code generation
460 -fobject-code
462 Generate object code
463 -fPIC Generate position-independent code (where available)
465 -fPIE Generate code for a position-independent executable (where
467 available)
468 -fwrite-interface
470 Always write interface files
471 -split-objs
473 Split generated object files into smaller files
474 Debugging the compiler
476 -dasm-lint
477 ASM pass sanity checking
478 -dcmm-lint
480 C-\- pass sanity checking
481 -dcore-lint
483 Turn on internal sanity checking
484 -ddump-asm
486 Dump final assembly
487 -ddump-asm-conflicts
489 Dump register conflicts from the register allocator.
490 -ddump-asm-liveness
492 Dump assembly augmented with register liveness
493 -ddump-asm-native
495 Dump initial assembly
496 -ddump-asm-regalloc
498 Dump the result of register allocation
499 -ddump-asm-regalloc-stages
501 Dump the build/spill stages of the -fregs-graph register alloca‐
502 tor.
503 -ddump-asm-stats
505 Dump statistics from the register allocator.
506 -ddump-bcos
508 Dump interpreter byte code
509 -ddump-c-backend
511 Dump C code produced by the C (unregisterised) backend.
512 -ddump-call-arity
514 Dump output of the call arity analysis pass.
515 -ddump-cfg-weights
517 Dump the assumed weights of the CFG.
518 -ddump-cmm
520 Dump the final C-\- output
521 -ddump-cmm-caf
523 Dump the results of the C-\- CAF analysis pass.
524 -ddump-cmm-cbe
526 Dump the results of common block elimination
527 -ddump-cmm-cfg
529 Dump the results of the C-\- control flow optimisation pass.
530 -ddump-cmm-cps
532 Dump the results of the CPS pass
533 -ddump-cmm-from-stg
535 Dump STG-to-C-\- output
536 -ddump-cmm-info
538 Dump the results of the C-\- info table augmentation pass.
539 -ddump-cmm-opt
541 Dump the results of C-\- to C-\- optimising passes
542 -ddump-cmm-proc
544 Dump the results of proc-point analysis
545 -ddump-cmm-procmap
547 Dump the results of the C-\- proc-point map pass.
548 -ddump-cmm-raw
550 Dump raw C-\-
551 -ddump-cmm-sink
553 Dump the results of the C-\- sinking pass.
554 -ddump-cmm-sp
556 Dump the results of the C-\- stack layout pass.
557 -ddump-cmm-split
559 Dump the results of the C-\- proc-point splitting pass.
560 -ddump-cmm-switch
562 Dump the results of switch lowering passes
563 -ddump-cmm-verbose
565 Write output from main C-\- pipeline passes to files
566 -ddump-cmm-verbose-by-proc
568 Show output from main C-\- pipeline passes (grouped by proc)
569 -ddump-core-stats
571 Print a one-line summary of the size of the Core program at the
572 end of the optimisation pipeline
573 -ddump-cpr-signatures
575 Dump CPR signatures
576 -ddump-cpranal
578 Dump CPR analysis output
579 -ddump-cs-trace
581 Trace constraint solver
582 -ddump-cse
584 Dump CSE output
585 -ddump-debug
587 Dump generated DWARF debug information
588 -ddump-deriv
590 Dump deriving output
591 -ddump-ds
593 Dump desugarer output.
594 -ddump-ec-trace
596 Trace exhaustiveness checker
597 -ddump-exitify
599 Dump output of the exitification pass.
600 -ddump-faststrings
602 Dump the whole FastString table when finished
603 -ddump-file-prefix=⟨str⟩
605 Set the prefix of the filenames used for debugging output.
606 -ddump-foreign
608 Dump foreign export stubs
609 -ddump-hie
611 Dump the hie file syntax tree
612 -ddump-hpc
614 An alias for -ddump-ticked.
615 -ddump-if-trace
617 Trace interface files
618 -ddump-inlinings
620 Dump inlinings performed by the simplifier.
621 -ddump-json
623 Dump error messages as JSON documents
624 -ddump-late-cc
626 Dump core with late cost centres added
627 -ddump-llvm
629 Dump LLVM intermediate code.
630 -ddump-mod-map
632 Dump the state of the module mapping database.
633 -ddump-occur-anal
635 Dump occurrence analysis output
636 -ddump-opt-cmm
638 Dump the results of C-\- to C-\- optimising passes
639 -ddump-parsed
641 Dump parse tree
642 -ddump-parsed-ast
644 Dump parser output as a syntax tree
645 -ddump-prep
647 Dump prepared core
648 -ddump-rn
650 Dump renamer output
651 -ddump-rn-ast
653 Dump renamer output as a syntax tree
654 -ddump-rn-stats
656 Renamer stats
657 -ddump-rn-trace
659 Trace renamer
660 -ddump-rtti
662 Trace runtime type inference
663 -ddump-rule-firings
665 Dump rule firing info
666 -ddump-rule-rewrites
668 Dump detailed rule firing info
669 -ddump-rules
671 Dump rewrite rules
672 -ddump-simpl
674 Dump final simplifier output
675 -ddump-simpl-iterations
677 Dump output from each simplifier iteration
678 -ddump-simpl-stats
680 Dump simplifier stats
681 -ddump-simpl-trace
683 Dump trace messages in simplifier
684 -ddump-spec
686 Dump specialiser output
687 -ddump-splices
689 Dump TH spliced expressions, and what they evaluate to
690 -ddump-stg
692 (deprecated) Alias for -ddump-stg-from-core
693 -ddump-stg-cg
695 Show output after Stg2Stg
696 -ddump-stg-final
698 Show output of last STG pass.
699 -ddump-stg-from-core
701 Show CoreToStg output
702 -ddump-stg-tags
704 Show output of the tag inference pass.
705 -ddump-stg-unarised
707 Show unarised STG
708 -ddump-str-signatures
710 Dump top-level demand signatures
711 -ddump-stranal
713 Dump demand analysis output
714 -ddump-tc
716 Dump typechecker output
717 -ddump-tc-ast
719 Dump typechecker output as a syntax tree
720 -ddump-tc-trace
722 Trace typechecker
723 -ddump-ticked
725 Dump the code instrumented by HPC (Observing Code Coverage).
726 -ddump-timings
728 Dump per-pass timing and allocation statistics
729 -ddump-to-file
731 Dump to files instead of stdout
732 -ddump-types
734 Dump type signatures
735 -ddump-verbose-inlinings
737 Dump all considered inlinings
738 -ddump-view-pattern-commoning
740 Dump commoned view patterns
741 -ddump-worker-wrapper
743 Dump worker-wrapper output
744 -dfaststring-stats
746 Show statistics for fast string usage when finished
747 -dhex-word-literals
749 Print values of type Word# in hexadecimal.
750 -dinitial-unique=⟨s⟩
752 Start UniqSupply allocation from ⟨s⟩.
753 -dinline-check=⟨str⟩
755 Dump information about inlining decisions
756 -dkeep-comments
758 Include comments in the parser. Useful in combination with
759 -ddump-parsed-ast.
760 -dlinear-core-lint
762 Turn on internal sanity checking
763 -dlint Enable several common internal sanity checkers
765 -dno-debug-output
767 Suppress unsolicited debugging output
768 -dno-typeable-binds
770 Don't generate bindings for Typeable methods
771 -dppr-case-as-let
773 Print single alternative case expressions as strict lets.
774 -dppr-cols=⟨n⟩
776 Set the width of debugging output. For example -dppr-cols200
777 -dppr-debug
779 Turn on debug printing (more verbose)
780 -dppr-user-length
782 Set the depth for printing expressions in error msgs
783 -drule-check=⟨str⟩
785 Dump information about potential rule application
786 -dshow-passes
788 Print out each pass name as it happens
789 -dstg-lint
791 STG pass sanity checking
792 -dsuppress-all
794 In dumps, suppress everything (except for uniques) that is sup‐
795 pressible.
796 -dsuppress-coercion-types
798 Suppress the printing of coercion types in Core dumps to make
799 them shorter
800 -dsuppress-coercions
802 Suppress the printing of coercions in Core dumps to make them
803 shorter
804 -dsuppress-core-sizes
806 Suppress the printing of core size stats per binding (since 9.4)
807 -dsuppress-idinfo
809 Suppress extended information about identifiers where they are
810 bound
811 -dsuppress-module-prefixes
813 Suppress the printing of module qualification prefixes
814 -dsuppress-stg-free-vars
816 Suppress the printing of closure free variable lists in STG out‐
817 put
818 -dsuppress-stg-reps
820 Suppress rep annotations on STG args.
821 -dsuppress-ticks
823 Suppress "ticks" in the pretty-printer output.
824 -dsuppress-timestamps
826 Suppress timestamps in dumps
827 -dsuppress-type-applications
829 Suppress type applications
830 -dsuppress-type-signatures
832 Suppress type signatures
833 -dsuppress-unfoldings
835 Suppress the printing of the stable unfolding of a variable at
836 its binding site
837 -dsuppress-uniques
839 Suppress the printing of uniques in debug output (easier to use
840 diff)
841 -dsuppress-var-kinds
843 Suppress the printing of variable kinds
844 -dtag-inference-checks
846 Affirm tag inference results are correct at runtime.
847 -dth-dec-file
849 Dump evaluated TH declarations into *.th.hs files
850 -dunique-increment=⟨i⟩
852 Set the increment for the generated Unique's to ⟨i⟩.
853 -dverbose-core2core
855 Show output from each core-to-core pass
856 -dverbose-stg2stg
858 Show output from each STG-to-STG pass
859 -falignment-sanitisation
861 Compile with alignment checks for all info table dereferences.
862 -fcatch-nonexhaustive-cases
864 Add a default error alternative to case expressions without a
865 default alternative.
866 -fcheck-prim-bounds
868 Instrument array primops with bounds checks.
869 -fdistinct-constructor-tables
871 Generate a fresh info table for each usage of a data construc‐
872 tor.
873 -finfo-table-map
875 Embed a lookup table in the generated binary which maps the ad‐
876 dress of an info table to the source position the closure origi‐
877 nated from.
878 -fllvm-fill-undef-with-garbage
880 Intruct LLVM to fill dead STG registers with garbage
881 -fproc-alignment
883 Align functions at given boundary.
884 -g Produce DWARF debug information in compiled object files. ⟨n⟩
886 can be 0, 1, or 2, with higher numbers producing richer output.
887 If ⟨n⟩ is omitted, level 2 is assumed.
888 C pre-processor
890 -cpp Run the C pre-processor on Haskell source files
891 -D⟨symbol⟩[=⟨value⟩]
893 Define a symbol in the C pre-processor
894 -I⟨dir⟩
896 Add ⟨dir⟩ to the directory search list for #include files
897 -U⟨symbol⟩
899 Undefine a symbol in the C pre-processor
900 Finding imports
902 -i Empty the import directory list
903 -i⟨dir⟩[:⟨dir⟩]*
905 add ⟨dir⟩, ⟨dir2⟩, etc. to import path
906 Interactive mode
908 -fbreak-on-error
909 Break on uncaught exceptions and errors
910 -fbreak-on-exception
912 Break on any exception thrown
913 -fghci-hist-size=⟨n⟩
915 Set the number of entries GHCi keeps for :history. See The GHCi
916 Debugger.
917 -fghci-leak-check
919 (Debugging only) check for space leaks when loading new modules
920 in GHCi.
921 -fimplicit-import-qualified
923 Put in scope qualified identifiers for every loaded module
924 -flocal-ghci-history
926 Use current directory for the GHCi command history file
927 .ghci-history.
928 -fno-it
930 No longer set the special variable it.
931 -fprint-bind-result
933 Turn on printing of binding results in GHCi
934 -fprint-evld-with-show
936 Instruct :print to use Show instances where possible.
937 -fshow-loaded-modules
939 Show the names of modules that GHCi loaded after a :load com‐
940 mand.
941 -ghci-script
943 Read additional .ghci files
944 -ignore-dot-ghci
946 Disable reading of .ghci files
947 -interactive-print ⟨name⟩
949 Select the function to use for printing evaluated expressions in
950 GHCi
951 Interface files
953 --show-iface ⟨file⟩
954 See Modes of operation.
955 -ddump-hi
957 Dump the new interface to stdout
958 -ddump-hi-diffs
960 Show the differences vs. the old interface
961 -ddump-minimal-imports
963 Dump a minimal set of imports
964 Keeping intermediate files
966 -keep-hc-file
967 Retain intermediate .hc files.
968 -keep-hi-files
970 Retain intermediate .hi files (the default).
971 -keep-hscpp-file
973 Retain intermediate .hscpp files.
974 -keep-llvm-file
976 Retain intermediate LLVM .ll files. Implies -fllvm.
977 -keep-o-files
979 Retain intermediate .o files (the default).
980 -keep-s-file
982 Retain intermediate .s files.
983 -keep-tmp-files
985 Retain all intermediate temporary files.
986 Language options
988 -XAllowAmbiguousTypes
989 Allow the user to write ambiguous types, and the type inference
990 engine to infer them.
991 -XApplicativeDo
993 Enable Applicative do-notation desugaring
994 -XArrows
996 Enable arrow notation extension
997 -XBangPatterns
999 Enable bang patterns.
1000 -XBinaryLiterals
1002 Enable support for binary literals.
1003 -XBlockArguments
1005 Allow do blocks and other constructs as function arguments.
1006 -XCApiFFI
1008 Enable the CAPI calling convention.
1009 -XConstrainedClassMethods
1011 Enable constrained class methods.
1012 -XConstraintKinds
1014 Enable a kind of constraints.
1015 -XCPP Enable the C preprocessor.
1017 -XCUSKs
1019 Enable detection of complete user-supplied kind signatures.
1020 -XDataKinds
1022 Enable datatype promotion.
1023 -XDatatypeContexts
1025 Allow contexts on data types.
1026 -XDeepSubsumption
1028 Enable deep subsumption
1029 -XDefaultSignatures
1031 Enable default signatures.
1032 -XDeriveAnyClass
1034 Enable deriving for any class.
1035 -XDeriveDataTypeable
1037 Enable deriving for the Data class. Implied by (deprecated) Au‐
1038 toDeriveTypeable.
1039 -XDeriveFoldable
1041 Enable deriving for the Foldable class. Implied by
1042 DeriveTraversable.
1043 -XDeriveFunctor
1045 Enable deriving for the Functor class. Implied by
1046 DeriveTraversable.
1047 -XDeriveGeneric
1049 Enable deriving for the Generic class.
1050 -XDeriveLift
1052 Enable deriving for the Lift class
1053 -XDeriveTraversable
1055 Enable deriving for the Traversable class. Implies
1056 DeriveFunctor and DeriveFoldable.
1057 -XDerivingStrategies
1059 Enables deriving strategies.
1060 -XDerivingVia
1062 Enable deriving instances via types of the same runtime repre‐
1063 sentation. Implies DerivingStrategies.
1064 -XDisambiguateRecordFields
1066 Enable record field disambiguation. Implied by RecordWildCards.
1067 -XDuplicateRecordFields
1069 Allow definition of record types with identically-named fields.
1070 -XEmptyCase
1072 Allow empty case alternatives.
1073 -XEmptyDataDecls
1075 Allow definition of empty data types.
1076 -XEmptyDataDeriving
1078 Allow deriving instances of standard type classes for empty data
1079 types.
1080 -XExistentialQuantification
1082 Enable liberalised type synonyms.
1083 -XExplicitForAll
1085 Enable explicit universal quantification. Implied by
1086 ScopedTypeVariables, LiberalTypeSynonyms, RankNTypes and
1087 ExistentialQuantification.
1088 -XExplicitNamespaces
1090 Enable using the keyword type to specify the namespace of en‐
1091 tries in imports and exports (Explicit namespaces in import/ex‐
1092 port). Implied by TypeOperators and TypeFamilies.
1093 -XExtendedDefaultRules
1095 Use GHCi's extended default rules in a normal module.
1096 -XFieldSelectors
1098 Control visibility of field selector functions.
1099 -XFlexibleContexts
1101 Remove some restrictions on class contexts
1102 -XFlexibleInstances
1104 Enable flexible instances. Implies TypeSynonymInstances.
1105 -XForeignFunctionInterface
1107 Enable foreign function interface.
1108 -XFunctionalDependencies
1110 Enable functional dependencies. Implies MultiParamTypeClasses.
1111 -XGADTs
1113 Enable generalised algebraic data types. Implies GADTSyntax and
1114 MonoLocalBinds.
1115 -XGADTSyntax
1117 Enable generalised algebraic data type syntax.
1118 -XGeneralisedNewtypeDeriving
1120 Enable newtype deriving.
1121 -XGeneralizedNewtypeDeriving
1123 Enable newtype deriving.
1124 -XGHC2021
1126 Use GHC’s set of default language extensions from 2021
1127 -XGHCForeignImportPrim
1129 Enable prim calling convention. Intended for internal use only.
1130 -XHaskell2010
1132 Use the Haskell 2010 language variant.
1133 -XHaskell98
1135 Use the Haskell 98 language variant.
1136 -XHexFloatLiterals
1138 Enable support for hexadecimal floating point literals.
1139 -XImplicitParams
1141 Enable Implicit Parameters.
1142 -XImportQualifiedPost
1144 ImportQualifiedPost allows the syntax import M qualified
1145 -XImpredicativeTypes
1147 Enable impredicative types. Implies RankNTypes.
1148 -XIncoherentInstances
1150 Enable incoherent instances. Implies OverlappingInstances.
1151 -XInstanceSigs
1153 Enable instance signatures.
1154 -XInterruptibleFFI
1156 Enable interruptible FFI.
1157 -XKindSignatures
1159 Enable kind signatures. Implied by TypeFamilies and PolyKinds.
1160 -XLambdaCase
1162 Enable lambda-case expressions.
1163 -XLexicalNegation
1165 Use whitespace to determine whether the minus sign stands for
1166 negation or subtraction.
1167 -XLiberalTypeSynonyms
1169 Enable liberalised type synonyms.
1170 -XLinearTypes
1172 Enable linear types.
1173 -XMagicHash
1175 Allow # as a postfix modifier on identifiers.
1176 -XMonadComprehensions
1178 Enable monad comprehensions.
1179 -XMonoLocalBinds
1181 Enable do not generalise local bindings. Implied by
1182 TypeFamilies and GADTs.
1183 -XMultiParamTypeClasses
1185 Enable multi parameter type classes. Implied by
1186 FunctionalDependencies.
1187 -XMultiWayIf
1189 Enable multi-way if-expressions.
1190 -XNamedFieldPuns
1192 Enable record puns.
1193 -XNamedWildCards
1195 Enable named wildcards.
1196 -XNegativeLiterals
1198 Enable support for negative literals.
1199 -XNoImplicitPrelude
1201 Don't implicitly import Prelude. Implied by RebindableSyntax.
1202 -XNoMonomorphismRestriction
1204 Disable the monomorphism restriction.
1205 -XNondecreasingIndentation
1207 Allow nested contexts to be at the same indentation level as its
1208 enclosing context.
1209 -XNoPatternGuards
1211 Disable pattern guards. Implied by Haskell98.
1212 -XNoTraditionalRecordSyntax
1214 Disable support for traditional record syntax (as supported by
1215 Haskell 98) C {f = x}
1216 -XNPlusKPatterns
1218 Enable support for n+k patterns. Implied by Haskell98.
1219 -XNullaryTypeClasses
1221 Deprecated, does nothing. nullary (no parameter) type classes
1222 are now enabled using MultiParamTypeClasses.
1223 -XNumDecimals
1225 Enable support for 'fractional' integer literals.
1226 -XNumericUnderscores
1228 Enable support for numeric underscores.
1229 -XOverlappingInstances
1231 Enable overlapping instances.
1232 -XOverloadedLabels
1234 Enable overloaded labels.
1235 -XOverloadedLists
1237 Enable overloaded lists.
1238 -XOverloadedRecordDot
1240 Record '.' syntax
1241 -XOverloadedRecordUpdate
1243 Record '.' syntax record updates
1244 -XOverloadedStrings
1246 Enable overloaded string literals.
1247 -XPackageImports
1249 Enable package-qualified imports.
1250 -XParallelListComp
1252 Enable parallel list comprehensions.
1253 -XPartialTypeSignatures
1255 Enable partial type signatures.
1256 -XPatternSynonyms
1258 Enable pattern synonyms.
1259 -XPolyKinds
1261 Enable kind polymorphism. Implies KindSignatures.
1262 -XPostfixOperators
1264 Enable postfix operators.
1265 -XQualifiedDo
1267 Enable qualified do-notation desugaring.
1268 -XQuantifiedConstraints
1270 Allow forall quantifiers in constraints.
1271 -XQuasiQuotes
1273 Enable quasiquotation.
1274 -XRank2Types
1276 Enable rank-2 types. Synonym for RankNTypes.
1277 -XRankNTypes
1279 Enable rank-N types. Implied by ImpredicativeTypes.
1280 -XRebindableSyntax
1282 Employ rebindable syntax. Implies NoImplicitPrelude.
1283 -XRecordWildCards
1285 Enable record wildcards. Implies DisambiguateRecordFields.
1286 -XRecursiveDo
1288 Enable recursive do (mdo) notation.
1289 -XRoleAnnotations
1291 Enable role annotations.
1292 -XSafe Enable the Safe Haskell Safe mode.
1294 -XScopedTypeVariables
1296 Enable lexically-scoped type variables.
1297 -XStandaloneDeriving
1299 Enable standalone deriving.
1300 -XStandaloneKindSignatures
1302 Allow the use of standalone kind signatures.
1303 -XStarIsType
1305 Treat * as Data.Kind.Type.
1306 -XStaticPointers
1308 Enable static pointers.
1309 -XStrict
1311 Make bindings in the current module strict by default.
1312 -XStrictData
1314 Enable default strict datatype fields.
1315 -XTemplateHaskell
1317 Enable Template Haskell.
1318 -XTemplateHaskellQuotes
1320 Enable quotation subset of Template Haskell.
1321 -XTransformListComp
1323 Enable generalised list comprehensions.
1324 -XTrustworthy
1326 Enable the Safe Haskell Trustworthy mode.
1327 -XTupleSections
1329 Enable tuple sections.
1330 -XTypeApplications
1332 Enable type application syntax in terms, patterns and types.
1333 -XTypeFamilies
1335 Enable type families. Implies ExplicitNamespaces,
1336 KindSignatures, and MonoLocalBinds.
1337 -XTypeFamilyDependencies
1339 Enable injective type families. Implies TypeFamilies.
1340 -XTypeInType
1342 Deprecated. Enable kind polymorphism and datatype promotion.
1343 -XTypeOperators
1345 Enable type operators. Implies ExplicitNamespaces.
1346 -XTypeSynonymInstances
1348 Enable type synonyms in instance heads. Implied by
1349 FlexibleInstances.
1350 -XUnboxedSums
1352 Enable unboxed sums.
1353 -XUnboxedTuples
1355 Enable the use of unboxed tuple syntax.
1356 -XUndecidableInstances
1358 Enable undecidable instances.
1359 -XUndecidableSuperClasses
1361 Allow all superclass constraints, including those that may re‐
1362 sult in non-termination of the typechecker.
1363 -XUnicodeSyntax
1365 Enable unicode syntax.
1366 -XUnliftedDatatypes
1368 Enable unlifted data types.
1369 -XUnliftedFFITypes
1371 Enable unlifted FFI types
1372 -XUnliftedNewtypes
1374 Enable unlifted newtypes.
1375 -XUnsafe
1377 Enable Safe Haskell Unsafe mode.
1378 -XViewPatterns
1380 Enable view patterns.
1381 Linking options
1383 -c Stop after generating object (.o) file
1384 -debug Use the debugging runtime
1386 -dylib-install-name ⟨path⟩
1388 Set the install name (via -install_name passed to Apple's
1389 linker), specifying the full install path of the library file.
1390 Any libraries or executables that link with it later will pick
1391 up that path as their runtime search location for it. (Dar‐
1392 win/OS X only)
1393 -dynamic
1395 Build dynamically-linked object files and executables
1396 -dynload
1398 Selects one of a number of modes for finding shared libraries at
1399 runtime.
1400 -eventlog
1402 Enable runtime event tracing
1403 -fcompact-unwind
1405 Instruct the linker to produce a __compact_unwind section.
1406 -fkeep-cafs
1408 Do not garbage-collect CAFs (top-level expressions) at runtime
1409 -flink-rts
1411 Link the runtime when generating a shared or static library
1412 -fno-embed-manifest
1414 Do not embed the manifest in the executable (Windows only)
1415 -fno-gen-manifest
1417 Do not generate a manifest file (Windows only)
1418 -fno-shared-implib
1420 Don't generate an import library for a DLL (Windows only)
1421 -framework ⟨name⟩
1423 On Darwin/OS X/iOS only, link in the framework ⟨name⟩. This op‐
1424 tion corresponds to the -framework option for Apple's Linker.
1425 -framework-path ⟨dir⟩
1427 On Darwin/OS X/iOS only, add ⟨dir⟩ to the list of directories
1428 searched for frameworks. This option corresponds to the -F op‐
1429 tion for Apple's Linker.
1430 -fuse-rpaths
1432 Set the rpath based on -L flags
1433 -fwhole-archive-hs-libs
1435 When linking a binary executable, this inserts the flag
1436 -Wl,--whole-archive before any -l flags for Haskell libraries,
1437 and -Wl,--no-whole-archive afterwards
1438 -L ⟨dir⟩
1440 Add ⟨dir⟩ to the list of directories searched for libraries
1441 -l ⟨lib⟩
1443 Link in library ⟨lib⟩
1444 -main-is ⟨thing⟩
1446 Set main module and function
1447 -no-hs-main
1449 Don't assume this program contains main
1450 -no-link
1452 Stop after generating object (.o) file
1453 -no-pie
1455 Don't instruct the linker to produce a position-independent exe‐
1456 cutable.
1457 -no-rtsopts-suggestions
1459 Don't print RTS suggestions about linking with
1460 -rtsopts[=⟨none|some|all|ignore|ignoreAll⟩].
1461 -package ⟨name⟩
1463 Expose package ⟨pkg⟩
1464 -pie Instruct the linker to produce a position-independent exe‐
1466 cutable.
1467 -rdynamic
1469 This instructs the linker to add all symbols, not only used
1470 ones, to the dynamic symbol table. Currently Linux and Win‐
1471 dows/MinGW32 only. This is equivalent to using -optl -rdynamic
1472 on Linux, and -optl -export-all-symbols on Windows.
1473 -rtsopts[=⟨none|some|all|ignore|ignoreAll⟩]
1475 Control whether the RTS behaviour can be tweaked via com‐
1476 mand-line flags and the GHCRTS environment variable. Using none
1477 means no RTS flags can be given; some means only a minimum of
1478 safe options can be given (the default); all (or no argument at
1479 all) means that all RTS flags are permitted; ignore means RTS
1480 flags can be given, but are treated as regular arguments and
1481 passed to the Haskell program as arguments; ignoreAll is the
1482 same as ignore, but GHCRTS is also ignored. -rtsopts does not
1483 affect -with-rtsopts behavior; flags passed via -with-rtsopts
1484 are used regardless of -rtsopts.
1485 -shared
1487 Generate a shared library (as opposed to an executable)
1488 -split-sections
1490 Split sections for link-time dead-code stripping
1491 -static
1493 Use static Haskell libraries
1494 -staticlib
1496 Generate a standalone static library (as opposed to an exe‐
1497 cutable). This is useful when cross compiling. The library to‐
1498 gether with all its dependencies ends up in in a single static
1499 library that can be linked against.
1500 -threaded
1502 Use the threaded runtime
1503 -with-rtsopts=⟨opts⟩
1505 Set the default RTS options to ⟨opts⟩.
1506 Miscellaneous options
1508 -fexternal-interpreter
1509 Run interpreted code in a separate process
1510 -ffamily-application-cache
1512 Use a cache when reducing type family applications
1513 -fglasgow-exts
1515 Deprecated. Enable most language extensions; see Controlling ex‐
1516 tensions for exactly which ones.
1517 -fno-safe-haskell
1519 Disable Safe Haskell
1520 -ghcversion-file ⟨path to ghcversion.h⟩
1522 (GHC as a C compiler only) Use this ghcversion.h file
1523 -H ⟨size⟩
1525 Set the minimum size of the heap to ⟨size⟩
1526 -hidden-module ⟨module name⟩
1528 A module which should not be visible outside its unit.
1529 -j[⟨n⟩]
1531 When compiling with --make, compile ⟨n⟩ modules in parallel.
1532 -reexported-module ⟨module name⟩
1534 A module which should be reexported from this unit.
1535 -this-package-name ⟨unit-id⟩
1537 The name of the package which this module would be part of when
1538 installed.
1539 -unit @⟨filename⟩
1541 Specify the options to build a specific unit.
1542 -working-dir ⟨dir⟩
1544 Specify the directory a unit is expected to be compiled in.
1545 Modes of operation
1547 --frontend ⟨module⟩
1548 run GHC with the given frontend plugin; see Frontend plugins for
1549 details.
1550 --help Display help
1552 --info display information about the compiler
1554 --interactive
1556 Interactive mode - normally used by just running ghci; see Using
1557 GHCi for details.
1558 --make Build a multi-module Haskell program, automatically figuring out
1560 dependencies. Likely to be much easier, and faster, than using
1561 make; see Using ghc --make for details.
1562 --numeric-version
1564 display GHC version (numeric only)
1565 --print-booter-version
1567 display bootstrap compiler version
1568 --print-build-platform
1570 display platform on which GHC was built
1571 --print-c-compiler-flags
1573 C compiler flags used to build GHC
1574 --print-c-compiler-link-flags
1576 C linker flags used to build GHC
1577 --print-debug-on
1579 print whether GHC was built with -DDEBUG
1580 --print-global-package-db
1582 display GHC's global package database directory
1583 --print-have-interpreter
1585 display whether GHC was built with interactive support
1586 --print-have-native-code-generator
1588 display whether target platform has NCG support
1589 --print-host-platform
1591 display host platform of GHC
1592 --print-ld-flags
1594 display linker flags used to compile GHC
1595 --print-leading-underscore
1597 display use of leading underscores on symbol names
1598 --print-libdir
1600 display GHC library directory
1601 --print-object-splitting-supported
1603 display whether GHC supports object splitting
1604 --print-project-git-commit-id
1606 display Git commit id GHC is built from
1607 --print-project-version
1609 display GHC version
1610 --print-rts-ways
1612 display which way RTS was built
1613 --print-stage
1615 display stage number of GHC
1616 --print-support-smp
1618 display whether GHC was compiled with SMP support
1619 --print-tables-next-to-code
1621 display whether GHC was compiled with --enable-ta‐
1622 bles-next-to-code
1623 --print-target-platform
1625 display target platform of GHC
1626 --print-unregisterised
1628 display whether this GHC was built in unregisterised mode
1629 --run ⟨file⟩
1631 Run a Haskell program.
1632 --show-iface ⟨file⟩
1634 display the contents of an interface file.
1635 --show-options
1637 display the supported command line options
1638 --supported-extensions
1640 display the supported language extensions
1641 --version
1643 display GHC version
1644 -e ⟨expr⟩
1646 Evaluate expr; see Expression evaluation mode for details.
1647 -M generate dependency information suitable for use in a Makefile;
1649 see Dependency generation for details.
1650 -shared
1652 Create a shared object.
1653 Individual optimizations
1655 -fasm-shortcutting
1656 Enable shortcutting on assembly. Implied by -O2.
1657 -fbinary-blob-threshold=⟨n⟩
1659 default: 500K. Tweak assembly generator for binary blobs.
1660 -fblock-layout-cfg
1662 Use the new cfg based block layout algorithm.
1663 -fblock-layout-weightless
1665 Ignore cfg weights for code layout.
1666 -fblock-layout-weights
1668 Sets edge weights used by the new code layout algorithm.
1669 -fcall-arity
1671 Enable call-arity optimisation. Implied by -O.
1672 -fcase-folding
1674 Enable constant folding in case expressions. Implied by -O.
1675 -fcase-merge
1677 Enable case-merging. Implied by -O.
1678 -fcmm-control-flow
1680 Enable control flow optimisation in the Cmm backend. Implied by
1681 -O.
1682 -fcmm-elim-common-blocks
1684 Enable Cmm common block elimination. Implied by -O.
1685 -fcmm-sink
1687 Enable Cmm sinking. Implied by -O.
1688 -fcmm-static-pred
1690 Enable static control flow prediction. Implied by -O.
1691 -fcore-constant-folding
1693 Enable constant folding in Core. Implied by -O.
1694 -fcpr-anal
1696 Turn on Constructed Product Result analysis. Implied by -O.
1697 -fcross-module-specialise
1699 Turn on specialisation of overloaded functions imported from
1700 other modules.
1701 -fcse Enable common sub-expression elimination. Implied by -O.
1703 -fdicts-cheap
1705 Make dictionary-valued expressions seem cheap to the optimiser.
1706 -fdicts-strict
1708 Make dictionaries strict. Implied by -O2.
1709 -fdmd-tx-dict-sel
1711 (deprecated) Use a special demand transformer for dictionary se‐
1712 lectors.
1713 -fdmd-unbox-width=⟨n⟩
1715 default: 3. Boxity analysis pretends that returned records with
1716 this many fields can be unboxed.
1717 -fdo-eta-reduction
1719 Enable eta-reduction. Implied by -O.
1720 -fdo-lambda-eta-expansion
1722 Enable lambda eta-expansion. Always enabled by default.
1723 -feager-blackholing
1725 Turn on eager blackholing
1726 -fenable-rewrite-rules
1728 Switch on all rewrite rules (including rules generated by auto‐
1729 matic specialisation of overloaded functions). Implied by -O.
1730 -fexcess-precision
1732 Enable excess intermediate precision
1733 -fexitification
1735 Enables exitification optimisation. Implied by -O.
1736 -fexpose-all-unfoldings
1738 Expose all unfoldings, even for very large or recursive func‐
1739 tions.
1740 -ffloat-in
1742 Turn on the float-in transformation. Implied by -O.
1743 -ffull-laziness
1745 Turn on full laziness (floating bindings outwards). Implied by
1746 -O.
1747 -ffun-to-thunk
1749 (deprecated) superseded by -ffull-laziness.
1750 -fignore-asserts
1752 Ignore assertions in the source. Implied by -O.
1753 -fignore-interface-pragmas
1755 Ignore pragmas in interface files. Implied by -O0 only.
1756 -finline-generics
1758 Annotate methods of derived Generic and Generic1 instances with
1759 INLINE[1] pragmas based on heuristics. Implied by -O.
1760 -finline-generics-aggressively
1762 Annotate methods of all derived Generic and Generic1 instances
1763 with INLINE[1] pragmas.
1764 -flate-dmd-anal
1766 Run demand analysis again, at the end of the simplification
1767 pipeline
1768 -flate-specialise
1770 Run a late specialisation pass
1771 -fliberate-case
1773 Turn on the liberate-case transformation. Implied by -O2.
1774 -fliberate-case-threshold=⟨n⟩
1776 default: 2000. Set the size threshold for the liberate-case
1777 transformation to ⟨n⟩
1778 -fllvm-pass-vectors-in-regs
1780 (deprecated) Does nothing
1781 -floopification
1783 Turn saturated self-recursive tail-calls into local jumps in the
1784 generated assembly. Implied by -O.
1785 -fmax-inline-alloc-size=⟨n⟩
1787 default: 128. Set the maximum size of inline array allocations
1788 to ⟨n⟩ bytes (default: 128).
1789 -fmax-inline-memcpy-insns=⟨n⟩
1791 default: 32. Inline memcpy calls if they would generate no more
1792 than ⟨n⟩ pseudo instructions.
1793 -fmax-inline-memset-insns=⟨n⟩
1795 default: 32. Inline memset calls if they would generate no more
1796 than ⟨n⟩ pseudo instructions
1797 -fmax-simplifier-iterations=⟨n⟩
1799 default: 4. Set the max iterations for the simplifier.
1800 -fmax-uncovered-patterns=⟨n⟩
1802 default: 4. Set the maximum number of patterns to display in
1803 warnings about non-exhaustive ones.
1804 -fmax-worker-args=⟨n⟩
1806 default: 10. Maximum number of value arguments for a worker.
1807 -fno-opt-coercion
1809 Turn off the coercion optimiser
1810 -fno-pre-inlining
1812 Turn off pre-inlining
1813 -fno-state-hack
1815 Turn off the state hackwhereby any lambda with a real-world
1816 state token as argument is considered to be single-entry. Hence
1817 OK to inline things inside it.
1818 -fomit-interface-pragmas
1820 Don't generate interface pragmas. Implied by -O0 only.
1821 -fomit-yields
1823 Omit heap checks when no allocation is being performed.
1824 -foptimal-applicative-do
1826 Use a slower but better algorithm for ApplicativeDo
1827 -fpedantic-bottoms
1829 Make GHC be more precise about its treatment of bottom (but see
1830 also -fno-state-hack). In particular, GHC will not eta-expand
1831 through a case expression.
1832 -fregs-graph
1834 Use the graph colouring register allocator for register alloca‐
1835 tion in the native code generator.
1836 -fregs-iterative
1838 Use the iterative coalescing graph colouring register allocator
1839 in the native code generator.
1840 -fsimpl-tick-factor=⟨n⟩
1842 default: 100. Set the percentage factor for simplifier ticks.
1843 -fsimplifier-phases=⟨n⟩
1845 default: 2. Set the number of phases for the simplifier. Ig‐
1846 nored with -O0.
1847 -fsolve-constant-dicts
1849 When solving constraints, try to eagerly solve super classes us‐
1850 ing available dictionaries.
1851 -fspec-constr
1853 Turn on the SpecConstr transformation. Implied by -O2.
1854 -fspec-constr-count=⟨n⟩
1856 default: 3.* Set to ⟨n⟩ the maximum number of specialisations
1857 that will be created for any one function by the SpecConstr
1858 transformation.
1859 -fspec-constr-keen
1861 Specialize a call with an explicit constructor argument, even if
1862 the argument is not scrutinised in the body of the function
1863 -fspec-constr-threshold=⟨n⟩
1865 default: 2000. Set the size threshold for the SpecConstr trans‐
1866 formation to ⟨n⟩.
1867 -fspecialise
1869 Turn on specialisation of overloaded functions. Implied by -O.
1870 -fspecialise-aggressively
1872 Turn on specialisation of overloaded functions regardless of
1873 size, if unfolding is available
1874 -fstatic-argument-transformation
1876 Turn on the static argument transformation.
1877 -fstg-cse
1879 Enable common sub-expression elimination on the STG intermediate
1880 language
1881 -fstg-lift-lams
1883 Enable late lambda lifting on the STG intermediate language. Im‐
1884 plied by -O2.
1885 -fstg-lift-lams-known
1887 Allow turning known into unknown calls while performing late
1888 lambda lifting.
1889 -fstg-lift-lams-non-rec-args
1891 Create top-level non-recursive functions with at most <n> param‐
1892 eters while performing late lambda lifting.
1893 -fstg-lift-lams-rec-args
1895 Create top-level recursive functions with at most <n> parameters
1896 while performing late lambda lifting.
1897 -fstrictness
1899 Turn on demand analysis. Implied by -O. Implies
1900 -fworker-wrapper
1901 -fstrictness-before=⟨n⟩
1903 Run an additional demand analysis before simplifier phase ⟨n⟩
1904 -funbox-small-strict-fields
1906 Flatten strict constructor fields with a pointer-sized represen‐
1907 tation. Implied by -O.
1908 -funbox-strict-fields
1910 Flatten strict constructor fields
1911 -funfolding-case-scaling=⟨n⟩
1913 default: 30. Apply a penalty of (inlining_cost * 1/n) for each
1914 level of case nesting.
1915 -funfolding-case-threshold=⟨n⟩
1917 default: 2. Reduce inlining for cases nested deeper than n.
1918 -funfolding-creation-threshold=⟨n⟩
1920 default: 750. Tweak unfolding settings.
1921 -funfolding-dict-discount=⟨n⟩
1923 default: 30. Tweak unfolding settings.
1924 -funfolding-fun-discount=⟨n⟩
1926 default: 60. Tweak unfolding settings.
1927 -funfolding-keeness-factor=⟨n⟩
1929 This has been deprecated in GHC 9.0.1.
1930 -funfolding-use-threshold=⟨n⟩
1932 default: 80. Tweak unfolding settings.
1933 -fworker-wrapper
1935 Enable the worker/wrapper transformation.
1936 -fworker-wrapper-cbv
1938 Enable w/w splits for wrappers whos sole purpose is evaluating
1939 arguments.
1940 Optimization levels
1942 -O Enable level 1 optimisations
1943 -O0 Disable optimisations (default)
1945 -O2 Enable level 2 optimisations
1947 -O⟨n⟩ Any -On where n > 2 is the same as -O2.
1949 Package options
1951 -clear-package-db
1952 Clear the package db stack.
1953 -distrust ⟨pkg⟩
1955 Expose package ⟨pkg⟩ and set it to be distrusted. See Safe
1956 Haskell.
1957 -distrust-all-packages
1959 Distrust all packages by default. See Safe Haskell.
1960 -fpackage-trust
1962 Enable Safe Haskell trusted package requirement for trustworthy
1963 modules.
1964 -global-package-db
1966 Add the global package db to the stack.
1967 -hide-all-packages
1969 Hide all packages by default
1970 -hide-package ⟨pkg⟩
1972 Hide package ⟨pkg⟩
1973 -ignore-package ⟨pkg⟩
1975 Ignore package ⟨pkg⟩
1976 -no-auto-link-packages
1978 Don't automatically link in the base and rts packages.
1979 -no-global-package-db
1981 Remove the global package db from the stack.
1982 -no-user-package-db
1984 Remove the user's package db from the stack.
1985 -package ⟨pkg⟩
1987 Expose package ⟨pkg⟩
1988 -package-db ⟨file⟩
1990 Add ⟨file⟩ to the package db stack.
1991 -package-env ⟨file⟩|⟨name⟩
1993 Use the specified package environment.
1994 -package-id ⟨unit-id⟩
1996 Expose package by id ⟨unit-id⟩
1997 -this-unit-id ⟨unit-id⟩
1999 Compile to be part of unit (i.e. package) ⟨unit-id⟩
2000 -trust ⟨pkg⟩
2002 Expose package ⟨pkg⟩ and set it to be trusted. See Safe Haskell.
2003 -user-package-db
2005 Add the user's package db to the stack.
2006 Phases of compilation
2008 --merge-objs
2009 Merge a set of objects into a GHCi library.
2010 -C Stop after generating C (.hc file)
2012 -c Stop after generating object (.o) file
2014 -E Stop after preprocessing (.hspp file)
2016 -F Enable the use of a pre-processor (set with -pgmF ⟨cmd⟩)
2018 -S Stop after generating assembly (.s file)
2020 -x ⟨suffix⟩
2022 Override default behaviour for source files
2023 Overriding external programs
2025 -pgma ⟨cmd⟩
2026 Use ⟨cmd⟩ as the assembler
2027 -pgmc ⟨cmd⟩
2029 Use ⟨cmd⟩ as the C compiler
2030 -pgmcxx ⟨cmd⟩
2032 Use ⟨cmd⟩ as the C++ compiler
2033 -pgmdll ⟨cmd⟩
2035 Use ⟨cmd⟩ as the DLL generator
2036 -pgmF ⟨cmd⟩
2038 Use ⟨cmd⟩ as the pre-processor (with -F only)
2039 -pgmi ⟨cmd⟩
2041 Use ⟨cmd⟩ as the external interpreter command.
2042 -pgminstall_name_tool ⟨cmd⟩
2044 Use ⟨cmd⟩ as the program to inject runpath into mach-o dylibs on
2045 macOS
2046 -pgmL ⟨cmd⟩
2048 Use ⟨cmd⟩ as the literate pre-processor
2049 -pgml ⟨cmd⟩
2051 Use ⟨cmd⟩ as the linker
2052 -pgmlc ⟨cmd⟩
2054 Use ⟨cmd⟩ as the LLVM compiler
2055 -pgmlibtool ⟨cmd⟩
2057 Use ⟨cmd⟩ as the command for libtool (with -staticlib only).
2058 -pgmlm ⟨cmd⟩
2060 Use ⟨cmd⟩ as the linker when merging object files
2061 -pgmlo ⟨cmd⟩
2063 Use ⟨cmd⟩ as the LLVM optimiser
2064 -pgmotool ⟨cmd⟩
2066 Use ⟨cmd⟩ as the program to inspect mach-o dylibs on macOS
2067 -pgmP ⟨cmd⟩
2069 Use ⟨cmd⟩ as the C pre-processor (with -cpp only)
2070 -pgms ⟨cmd⟩
2072 Use ⟨cmd⟩ as the splitter
2073 -pgmwindres ⟨cmd⟩
2075 Use ⟨cmd⟩ as the program for embedding manifests on Windows.
2076 Phase-specific options
2078 -opta ⟨option⟩
2079 pass ⟨option⟩ to the assembler
2080 -optc ⟨option⟩
2082 pass ⟨option⟩ to the C compiler
2083 -optcxx ⟨option⟩
2085 pass ⟨option⟩ to the C++ compiler
2086 -optdll ⟨option⟩
2088 pass ⟨option⟩ to the DLL generator
2089 -optF ⟨option⟩
2091 pass ⟨option⟩ to the custom pre-processor
2092 -opti ⟨option⟩
2094 pass ⟨option⟩ to the interpreter sub-process.
2095 -optL ⟨option⟩
2097 pass ⟨option⟩ to the literate pre-processor
2098 -optl ⟨option⟩
2100 pass ⟨option⟩ to the linker
2101 -optlc ⟨option⟩
2103 pass ⟨option⟩ to the LLVM compiler
2104 -optlm ⟨option⟩
2106 pass ⟨option⟩ to the linker when merging object files.
2107 -optlo ⟨option⟩
2109 pass ⟨option⟩ to the LLVM optimiser
2110 -optP ⟨option⟩
2112 pass ⟨option⟩ to cpp (with -cpp only)
2113 -optwindres ⟨option⟩
2115 pass ⟨option⟩ to windres.
2116 -pgmc-supports-no-pie
2118 (deprecated) Indicate that the linker supports -no-pie
2119 -pgml-supports-no-pie
2121 Indicate that the linker supports -no-pie
2122 Platform-specific options
2124 -mavx (x86 only) Enable support for AVX SIMD extensions
2125 -mavx2 (x86 only) Enable support for AVX2 SIMD extensions
2127 -mavx512cd
2129 (x86 only) Enable support for AVX512-CD SIMD extensions
2130 -mavx512er
2132 (x86 only) Enable support for AVX512-ER SIMD extensions
2133 -mavx512f
2135 (x86 only) Enable support for AVX512-F SIMD extensions
2136 -mavx512pf
2138 (x86 only) Enable support for AVX512-PF SIMD extensions
2139 -mbmi (x86 only) Use BMI1 for bit manipulation operations
2141 -mbmi2 (x86 only) Use BMI2 for bit manipulation operations
2143 -msse (x86 only) Use SSE for floating-point operations
2145 -msse2 (x86 only) Use SSE2 for floating-point operations
2147 -msse3 (x86 only) Use SSE3 for floating-point operations
2149 -msse4 (x86 only) Use SSE4 for floating-point operations
2151 -msse4.2
2153 (x86 only) Use SSE4.2 for floating-point operations
2154 Compiler plugins
2156 -fclear-plugins
2157 Clear the list of active plugins
2158 -fplugin-opt=⟨module⟩:⟨args⟩
2160 Give arguments to a plugin module; module must be specified with
2161 -fplugin=⟨module⟩
2162 -fplugin-trustworthy
2164 Trust the used plugins and no longer mark the compiled module as
2165 unsafe
2166 -fplugin=⟨module⟩
2168 Load a plugin exported by a given module
2169 -hide-all-plugin-packages
2171 Hide all packages for plugins by default
2172 -plugin-package ⟨pkg⟩
2174 Expose ⟨pkg⟩ for plugins
2175 -plugin-package-id ⟨pkg-id⟩
2177 Expose ⟨pkg-id⟩ for plugins
2178 Profiling
2180 -auto (deprecated) Alias for -fprof-auto-exported
2181 -auto-all
2183 (deprecated) Alias for -fprof-auto
2184 -caf-all
2186 (deprecated) Alias for -fprof-cafs
2187 -fno-prof-count-entries
2189 Do not collect entry counts
2190 -fprof-auto
2192 Auto-add SCC\ s to all bindings not marked INLINE
2193 -fprof-auto-calls
2195 Auto-add SCC\ s to all call sites
2196 -fprof-auto-exported
2198 Auto-add SCC\ s to all exported bindings not marked INLINE
2199 -fprof-auto-top
2201 Auto-add SCC\ s to all top-level bindings not marked INLINE
2202 -fprof-cafs
2204 Auto-add SCC\ s to all CAFs
2205 -fprof-callers=⟨name⟩
2207 Auto-add SCC\ s to all call-sites of the named function.
2208 -fprof-late
2210 Auto-add SCC\ s to all top level bindings after the core pipe‐
2211 line has run.
2212 -fprof-late-inline
2214 Auto-add SCC\ s to all top level bindings after the optimizer
2215 has run and retain them when inlining.
2216 -fprof-manual
2218 Process manual SCC annotations.
2219 -no-auto
2221 (deprecated) Alias for -fno-prof-auto
2222 -no-auto-all
2224 (deprecated) Alias for -fno-prof-auto
2225 -no-caf-all
2227 (deprecated) Alias for -fno-prof-cafs
2228 -prof Turn on profiling
2230 -ticky Turn on ticky-ticky profiling
2232 -ticky-allocd
2234 Track the number of times each closure type is allocated.
2235 -ticky-ap-thunk
2237 Don't use standard AP thunks on order to get more reliable entry
2238 counters.
2239 -ticky-dyn-thunk
2241 Track allocations of dynamic thunks
2242 -ticky-LNE
2244 Treat join point binders similar to thunks/functions.
2245 -ticky-tag-checks
2247 Emit dummy ticky counters to record how many tag-inference
2248 checks tag inference avoided.
2249 Program coverage
2251 -fhpc Turn on Haskell program coverage instrumentation
2252 -hpcdir⟨dir⟩
2254 Set the directory where GHC places .mix files.
2255 Recompilation checking
2257 -fforce-recomp
2258 Turn off recompilation checking. This is implied by any -ddump-X
2259 option when compiling a single file (i.e. when using -c).
2260 -fignore-hpc-changes
2262 Do not recompile modules just to match changes to HPC flags.
2263 This is especially useful for avoiding recompilation when using
2264 GHCi, and is enabled by default for GHCi.
2265 -fignore-optim-changes
2267 Do not recompile modules just to match changes to optimisation
2268 flags. This is especially useful for avoiding recompilation when
2269 using GHCi, and is enabled by default for GHCi.
2270 Redirecting output
2272 --exclude-module=⟨file⟩
2273 Regard ⟨file⟩ as "stable"; i.e., exclude it from having depen‐
2274 dencies on it.
2275 -ddump-mod-cycles
2277 Dump module cycles
2278 -dep-makefile ⟨file⟩
2280 Use ⟨file⟩ as the makefile
2281 -dep-suffix ⟨suffix⟩
2283 Make dependencies that declare that files with suffix
2284 .⟨suf⟩⟨osuf⟩ depend on interface files with suffix .⟨suf⟩hi
2285 -dumpdir ⟨dir⟩
2287 redirect dump files
2288 -dynhisuf ⟨suffix⟩
2290 set the suffix to use for dynamic interface files
2291 -dyno ⟨file⟩
2293 set dynamic output filename
2294 -dynohi ⟨file⟩
2296 set the filename in which to put the dynamic interface
2297 -dynosuf ⟨suffix⟩
2299 set the dynamic output file suffix
2300 -hcsuf ⟨suffix⟩
2302 set the suffix to use for intermediate C files
2303 -hidir ⟨dir⟩
2305 set directory for interface files
2306 -hiedir ⟨dir⟩
2308 set directory for extended interface files
2309 -hiesuf ⟨suffix⟩
2311 set the suffix to use for extended interface files
2312 -hisuf ⟨suffix⟩
2314 set the suffix to use for interface files
2315 -include-cpp-deps
2317 Include preprocessor dependencies
2318 -include-pkg-deps
2320 Regard modules imported from packages as unstable
2321 -o ⟨file⟩
2323 set output filename
2324 -odir ⟨dir⟩
2326 set directory for object files
2327 -ohi ⟨file⟩
2329 set the filename in which to put the interface
2330 -osuf ⟨suffix⟩
2332 set the output file suffix
2333 -outputdir ⟨dir⟩
2335 set output directory
2336 -stubdir ⟨dir⟩
2338 redirect FFI stub files
2339 Temporary files
2341 -tmpdir ⟨dir⟩
2342 set the directory for temporary files
2343 Verbosity options
2345 -fabstract-refinement-hole-fits
2346 default: off. Toggles whether refinements where one or more of
2347 the holes are abstract are reported.
2348 -fdefer-diagnostics
2350 Defer and group diagnostic messages by severity
2351 -fdiagnostics-color=⟨always|auto|never⟩
2353 Use colors in error messages
2354 -fdiagnostics-show-caret
2356 Whether to show snippets of original source code
2357 -ferror-spans
2359 Output full span in error messages
2360 -fhide-source-paths
2362 hide module source and object paths
2363 -fkeep-going
2365 Continue compilation as far as possible on errors
2366 -fmax-refinement-hole-fits=⟨n⟩
2368 default: 6. Set the maximum number of refinement hole fits for
2369 typed holes to display in type error messages.
2370 -fmax-relevant-binds=⟨n⟩
2372 default: 6. Set the maximum number of bindings to display in
2373 type error messages.
2374 -fmax-valid-hole-fits=⟨n⟩
2376 default: 6. Set the maximum number of valid hole fits for typed
2377 holes to display in type error messages.
2378 -fno-show-valid-hole-fits
2380 Disables showing a list of valid hole fits for typed holes in
2381 type error messages.
2382 -fno-sort-valid-hole-fits
2384 Disables the sorting of the list of valid hole fits for typed
2385 holes in type error messages.
2386 -fprint-axiom-incomps
2388 Display equation incompatibilities in closed type families
2389 -fprint-equality-relations
2391 Distinguish between equality relations when printing
2392 -fprint-expanded-synonyms
2394 In type errors, also print type-synonym-expanded types.
2395 -fprint-explicit-coercions
2397 Print coercions in types
2398 -fprint-explicit-foralls
2400 Print explicit forall quantification in types. See also
2401 ExplicitForAll
2402 -fprint-explicit-kinds
2404 Print explicit kind foralls and kind arguments in types. See
2405 also KindSignatures
2406 -fprint-explicit-runtime-reps
2408 Print RuntimeRep and Levity variables in types which are run‐
2409 time-representation polymorphic.
2410 -fprint-potential-instances
2412 display all available instances in type error messages
2413 -fprint-typechecker-elaboration
2415 Print extra information from typechecker.
2416 -fprint-unicode-syntax
2418 Use unicode syntax when printing expressions, types and kinds.
2419 See also UnicodeSyntax
2420 -frefinement-level-hole-fits=⟨n⟩
2422 default: off. Sets the level of refinement of the refinement
2423 hole fits, where level n means that hole fits of up to n holes
2424 will be considered.
2425 -freverse-errors
2427 Output errors in reverse order
2428 -fshow-docs-of-hole-fits
2430 Toggles whether to show the documentation of the valid hole fits
2431 in the output.
2432 -fshow-hole-constraints
2434 Show constraints when reporting typed holes.
2435 -fshow-hole-matches-of-hole-fits
2437 Toggles whether to show the type of the additional holes in re‐
2438 finement hole fits.
2439 -fshow-provenance-of-hole-fits
2441 Toggles whether to show the provenance of the valid hole fits in
2442 the output.
2443 -fshow-type-app-of-hole-fits
2445 Toggles whether to show the type application of the valid hole
2446 fits in the output.
2447 -fshow-type-app-vars-of-hole-fits
2449 Toggles whether to show what type each quantified variable takes
2450 in a valid hole fit.
2451 -fshow-type-of-hole-fits
2453 Toggles whether to show the type of the valid hole fits in the
2454 output.
2455 -fsort-by-size-hole-fits
2457 Sort valid hole fits by size.
2458 -fsort-by-subsumption-hole-fits
2460 Sort valid hole fits by subsumption.
2461 -funclutter-valid-hole-fits
2463 Unclutter the list of valid hole fits by not showing provenance
2464 nor type applications of suggestions.
2465 -Rghc-timing
2467 Summarise timing stats for GHC (same as +RTS -tstderr).
2468 -v verbose mode (equivalent to -v3)
2470 -v⟨n⟩ set verbosity level
2472 Warnings
2474 -fdefer-out-of-scope-variables
2475 Convert variable out of scope variables errors into warnings.
2476 Implied by -fdefer-type-errors. See also
2477 -Wdeferred-out-of-scope-variables.
2478 -fdefer-type-errors
2480 Turn type errors into warnings, deferring the error until run‐
2481 time. Implies -fdefer-typed-holes and
2482 -fdefer-out-of-scope-variables. See also -Wdeferred-type-errors
2483 -fdefer-typed-holes
2485 Convert typed hole errors into warnings, deferring the error un‐
2486 til runtime. Implied by -fdefer-type-errors. See also
2487 -Wtyped-holes.
2488 -fenable-th-splice-warnings
2490 Generate warnings for Template Haskell splices
2491 -fhelpful-errors
2493 Make suggestions for mis-spelled names.
2494 -fmax-pmcheck-models=⟨n⟩
2496 soft limit on the number of parallel models the pattern match
2497 checker should check a pattern match clause against
2498 -fshow-warning-groups
2500 show which group an emitted warning belongs to.
2501 -fvia-C
2503 use the C code generator
2504 -W enable normal warnings
2506 -w disable all warnings
2508 -Wall enable almost all warnings (details in Warnings and san‐
2510 ity-checking)
2511 -Wall-missed-specialisations
2513 warn when specialisation of any overloaded function fails.
2514 -Wall-missed-specializations
2516 alias for -Wall-missed-specialisations
2517 -Wambiguous-fields
2519 warn about ambiguous field selectors or updates
2520 -Wauto-orphans
2522 (deprecated) Does nothing
2523 -Wcompat
2525 enable future compatibility warnings (details in Warnings and
2526 sanity-checking)
2527 -Wcompat-unqualified-imports
2529 Report unqualified imports of core libraries which are expected
2530 to cause compatibility problems in future releases.
2531 -Wcpp-undef
2533 warn on uses of the #if directive on undefined identifiers
2534 -Wdefault
2536 enable default flags
2537 -Wdeferred-out-of-scope-variables
2539 Report warnings when variable out-of-scope errors are deferred
2540 until runtime. See -fdefer-out-of-scope-variables.
2541 -Wdeferred-type-errors
2543 Report warnings when deferred type errors are enabled. This op‐
2544 tion is enabled by default. See -fdefer-type-errors.
2545 -Wdeprecated-flags
2547 warn about uses of commandline flags that are deprecated
2548 -Wdeprecations
2550 warn about uses of functions & types that have warnings or dep‐
2551 recated pragmas. Alias for -Wwarnings-deprecations
2552 -Wderiving-defaults
2554 warn about default deriving when using both DeriveAnyClass and
2555 GeneralizedNewtypeDeriving
2556 -Wderiving-typeable
2558 warn when Typeable is derived
2559 -Wdodgy-exports
2561 warn about dodgy exports
2562 -Wdodgy-foreign-imports
2564 warn about dodgy foreign imports
2565 -Wdodgy-imports
2567 warn about dodgy imports
2568 -Wduplicate-constraints
2570 warn when a constraint appears duplicated in a type signature
2571 -Wduplicate-exports
2573 warn when an entity is exported multiple times
2574 -Wempty-enumerations
2576 warn about enumerations that are empty
2577 -Werror
2579 make warnings fatal
2580 -Weverything
2582 enable all warnings supported by GHC
2583 -Wextra
2585 alias for -W
2586 -Wforall-identifier
2588 warn when forall is used as an identifier (at definition sites)
2589 -Wgadt-mono-local-binds
2591 warn when pattern matching on a GADT without MonoLocalBinds
2592 -Whi-shadowing
2594 (deprecated) warn when a .hi file in the current directory shad‐
2595 ows a library
2596 -Widentities
2598 warn about uses of Prelude numeric conversions that are probably
2599 the identity (and hence could be omitted)
2600 -Wimplicit-kind-vars
2602 (deprecated) warn when kind variables are implicitly quantified
2603 over.
2604 -Wimplicit-lift
2606 warn about implicit lift in Template Haskell quotes
2607 -Wimplicit-prelude
2609 warn when the Prelude is implicitly imported
2610 -Winaccessible-code
2612 warn about inaccessible code
2613 -Wincomplete-patterns
2615 warn when a pattern match could fail
2616 -Wincomplete-record-updates
2618 warn when a record update could fail
2619 -Wincomplete-uni-patterns
2621 warn when a pattern match in a lambda expression, pattern bind‐
2622 ing or a lazy pattern could fail
2623 -Winferred-safe-imports
2625 warn when an explicitly Safe Haskell module imports a Safe-In‐
2626 ferred one
2627 -Winline-rule-shadowing
2629 Warn if a rewrite RULE might fail to fire because the function
2630 might be inlined before the rule has a chance to fire. See How
2631 rules interact with INLINE/NOINLINE pragmas.
2632 -Winvalid-haddock
2634 warn when a Haddock comment occurs in an invalid position
2635 -Wmisplaced-pragmas
2637 warn about uses of file header pragmas in the module body
2638 -Wmissed-extra-shared-lib
2640 Warn when GHCi can't load a shared lib.
2641 -Wmissed-specialisations
2643 warn when specialisation of an imported, overloaded function
2644 fails.
2645 -Wmissed-specializations
2647 alias for -Wmissed-specialisations
2648 -Wmissing-deriving-strategies
2650 warn when a deriving clause is missing a deriving strategy
2651 -Wmissing-export-lists
2653 warn when a module declaration does not explicitly list all ex‐
2654 ports
2655 -Wmissing-exported-pattern-synonym-signatures
2657 warn about pattern synonyms without signatures, only if they are
2658 exported
2659 -Wmissing-exported-signatures
2661 warn about top-level functions without signatures, only if they
2662 are exported
2663 -Wmissing-exported-sigs
2665 (deprecated) warn about top-level functions without signatures,
2666 only if they are exported. takes precedence over -Wmissing-sig‐
2667 natures
2668 -Wmissing-fields
2670 warn when fields of a record are uninitialised
2671 -Wmissing-home-modules
2673 warn when encountering a home module imported, but not listed on
2674 the command line. Useful for cabal to ensure GHC won't pick up
2675 modules, not listed neither in exposed-modules, nor in
2676 other-modules.
2677 -Wmissing-import-lists
2679 warn when an import declaration does not explicitly list all the
2680 names brought into scope
2681 -Wmissing-kind-signatures
2683 warn when type declarations don't have kind signatures nor CUSKs
2684 -Wmissing-local-signatures
2686 warn about polymorphic local bindings without signatures
2687 -Wmissing-local-sigs
2689 (deprecated) warn about polymorphic local bindings without sig‐
2690 natures
2691 -Wmissing-methods
2693 warn when class methods are undefined
2694 -Wmissing-monadfail-instances
2696 (deprecated) Warn when a failable pattern is used in a do-block
2697 that does not have a MonadFail instance.
2698 -Wmissing-pattern-synonym-signatures
2700 warn when pattern synonyms do not have type signatures
2701 -Wmissing-safe-haskell-mode
2703 warn when the Safe Haskell mode is not explicitly specified.
2704 -Wmissing-signatures
2706 warn about top-level functions without signatures
2707 -Wmissing-space-after-bang
2709 (deprecated) Does nothing
2710 -Wmonomorphism-restriction
2712 warn when the Monomorphism Restriction is applied
2713 -Wname-shadowing
2715 warn when names are shadowed
2716 -Wno-compat
2718 Disables all warnings enabled by -Wcompat.
2719 -Wnoncanonical-monad-instances
2721 warn when Applicative or Monad instances have noncanonical defi‐
2722 nitions of return, pure, (>>), or (*>). See flag description in
2723 Warnings and sanity-checking for more details.
2724 -Wnoncanonical-monadfail-instances
2726 (deprecated) warn when Monad or MonadFail instances have non‐
2727 canonical definitions of fail.
2728 -Wnoncanonical-monoid-instances
2730 warn when Semigroup or Monoid instances have noncanonical defi‐
2731 nitions of (<>) or mappend. See flag description in Warnings
2732 and sanity-checking for more details.
2733 -Wnot (deprecated) Alias for -w
2735 -Woperator-whitespace
2737 warn on prefix, suffix, and tight infix uses of infix operators
2738 -Woperator-whitespace-ext-conflict
2740 warn on uses of infix operators that would be parsed differently
2741 were a particular GHC extension enabled
2742 -Worphans
2744 warn when the module contains orphan instance declarations or
2745 rewrite rules
2746 -Woverflowed-literals
2748 warn about literals that will overflow their type
2749 -Woverlapping-patterns
2751 warn about overlapping patterns
2752 -Wpartial-fields
2754 warn when defining a partial record field.
2755 -Wpartial-type-signatures
2757 warn about holes in partial type signatures when
2758 PartialTypeSignatures is enabled. Not applicable when
2759 PartialTypeSignatures is not enabled, in which case errors are
2760 generated for such holes.
2761 -Wprepositive-qualified-module
2763 Report imports with a leading/prepositive "qualified"
2764 -Wredundant-bang-patterns
2766 Warn about redundant bang patterns.
2767 -Wredundant-constraints
2769 Have the compiler warn about redundant constraints in type sig‐
2770 natures.
2771 -Wredundant-record-wildcards
2773 Warn about record wildcard matches when the wildcard binds no
2774 patterns.
2775 -Wredundant-strictness-flags
2777 Warn about redundant strictness flags.
2778 -Wsafe warn if the module being compiled is regarded to be safe.
2780 -Wsemigroup
2782 warn when a Monoid is not Semigroup, and on non- Semigroup defi‐
2783 nitions of (<>)?
2784 -Wsimplifiable-class-constraints
2786 Warn about class constraints in a type signature that can be
2787 simplified using a top-level instance declaration.
2788 -Wstar-binder
2790 warn about binding the (*) type operator despite StarIsType
2791 -Wstar-is-type
2793 warn when * is used to mean Data.Kind.Type
2794 -Wtabs warn if there are tabs in the source file
2796 -Wtrustworthy-safe
2798 warn if the module being compiled is marked as Trustworthy but
2799 it could instead be marked as Safe, a more informative bound.
2800 -Wtype-defaults
2802 warn when defaulting happens
2803 -Wtype-equality-out-of-scope
2805 warn when type equality a ~ b is used despite being out of scope
2806 -Wtype-equality-requires-operators
2808 warn when type equality a ~ b is used despite being out of scope
2809 -Wtyped-holes
2811 Report warnings when typed hole errors are deferred until run‐
2812 time. See -fdefer-typed-holes.
2813 -Wunbanged-strict-patterns
2815 warn on pattern bind of unlifted variable that is neither bare
2816 nor banged
2817 -Wunicode-bidirectional-format-characters
2819 warn about the usage of unicode bidirectional layout override
2820 characters
2821 -Wunrecognised-pragmas
2823 warn about uses of pragmas that GHC doesn't recognise
2824 -Wunrecognised-warning-flags
2826 throw a warning when an unrecognised -W... flag is encountered
2827 on the command line.
2828 -Wunsafe
2830 warn if the module being compiled is regarded to be unsafe. See
2831 Safe Haskell
2832 -Wunsupported-calling-conventions
2834 warn about use of an unsupported calling convention
2835 -Wunsupported-llvm-version
2837 Warn when using -fllvm with an unsupported version of LLVM.
2838 -Wunticked-promoted-constructors
2840 warn if promoted constructors are not ticked
2841 -Wunused-binds
2843 warn about bindings that are unused. Alias for
2844 -Wunused-top-binds, -Wunused-local-binds and
2845 -Wunused-pattern-binds
2846 -Wunused-do-bind
2848 warn about do bindings that appear to throw away values of types
2849 other than ()
2850 -Wunused-foralls
2852 warn about type variables in user-written forall\s that are un‐
2853 used
2854 -Wunused-imports
2856 warn about unnecessary imports
2857 -Wunused-local-binds
2859 warn about local bindings that are unused
2860 -Wunused-matches
2862 warn about variables in patterns that aren't used
2863 -Wunused-packages
2865 warn when package is requested on command line, but not needed.
2866 -Wunused-pattern-binds
2868 warn about pattern match bindings that are unused
2869 -Wunused-record-wildcards
2871 Warn about record wildcard matches when none of the bound vari‐
2872 ables are used.
2873 -Wunused-top-binds
2875 warn about top-level bindings that are unused
2876 -Wunused-type-patterns
2878 warn about unused type variables which arise from patterns in in
2879 type family and data family instances
2880 -Wwarn make warnings non-fatal
2882 -Wwarnings-deprecations
2884 warn about uses of functions & types that have warnings or dep‐
2885 recated pragmas
2886 -Wwrong-do-bind
2888 warn about do bindings that appear to throw away monadic values
2889 that you should have bound instead
2890
2892 Copyright 2015. The University Court of the University of Glasgow. All
2893 rights reserved.
2894
2896 https://www.haskell.org/ghc the GHC homepage
2897
2899 The GHC Team
2900
2902 2023, GHC Team
29039.4.5 Aug 08, 2023 GHC(1)