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Diffstat (limited to 'docs/users_guide/exts/defer_type_errors.rst')
| -rw-r--r-- | docs/users_guide/exts/defer_type_errors.rst | 60 |
1 files changed, 59 insertions, 1 deletions
diff --git a/docs/users_guide/exts/defer_type_errors.rst b/docs/users_guide/exts/defer_type_errors.rst index a2647fc9ef..e2fda98e04 100644 --- a/docs/users_guide/exts/defer_type_errors.rst +++ b/docs/users_guide/exts/defer_type_errors.rst @@ -34,7 +34,7 @@ to suppress these warnings. This flag implies the :ghc-flag:`-fdefer-typed-holes` and :ghc-flag:`-fdefer-out-of-scope-variables` flags, which enables this behaviour -for `typed holes <#typed-holes>`__ and variables. Should you so wish, it is +for :ref:`typed-holes` and variables. Should you so wish, it is possible to enable :ghc-flag:`-fdefer-type-errors` without enabling :ghc-flag:`-fdefer-typed-holes` or :ghc-flag:`-fdefer-out-of-scope-variables`, by explicitly specifying :ghc-flag:`-fno-defer-typed-holes @@ -42,6 +42,64 @@ by explicitly specifying :ghc-flag:`-fno-defer-typed-holes <-fdefer-out-of-scope-variables>` on the command-line after the :ghc-flag:`-fdefer-type-errors` flag. +.. ghc-flag:: -fdefer-type-errors + :shortdesc: Turn type errors into warnings, :ref:`deferring the error until + runtime <defer-type-errors>`. Implies + :ghc-flag:`-fdefer-typed-holes` and + :ghc-flag:`-fdefer-out-of-scope-variables`. + See also :ghc-flag:`-Wdeferred-type-errors`. + :type: dynamic + :reverse: -fno-defer-type-errors + :category: + + :since: 7.6 + + :implies: :ghc-flag:`-fdefer-typed-holes`, :ghc-flag:`-fdefer-out-of-scope-variables` + + Defer as many type errors as possible until runtime. At compile time + you get a warning (instead of an error). At runtime, if you use a + value that depends on a type error, you get a runtime error; but you + can run any type-correct parts of your code just fine. + See also :ghc-flag:`-Wdeferred-type-errors`. + +.. ghc-flag:: -fdefer-typed-holes + :shortdesc: Convert :ref:`typed hole <typed-holes>` errors into warnings, + :ref:`deferring the error until runtime <defer-type-errors>`. + Implied by :ghc-flag:`-fdefer-type-errors`. + See also :ghc-flag:`-Wtyped-holes`. + :type: dynamic + :reverse: -fno-defer-typed-holes + :category: + + :since: 7.10 + + Defer typed holes errors (errors about names with a leading underscore + (e.g., “_”, “_foo”, “_bar”)) until runtime. This will turn the errors + produced by :ref:`typed holes <typed-holes>` into warnings. Using a value + that depends on a typed hole produces a runtime error, the same as + :ghc-flag:`-fdefer-type-errors` (which implies this option). See :ref:`typed-holes`. + + Implied by :ghc-flag:`-fdefer-type-errors`. See also :ghc-flag:`-Wtyped-holes`. + +.. ghc-flag:: -fdefer-out-of-scope-variables + :shortdesc: Convert variable out of scope variables errors into warnings. + Implied by :ghc-flag:`-fdefer-type-errors`. + See also :ghc-flag:`-Wdeferred-out-of-scope-variables`. + :type: dynamic + :reverse: -fno-defer-out-of-scope-variables + :category: + + :since: 8.0 + + Defer variable out-of-scope errors (errors about names without a leading underscore) + until runtime. This will turn variable-out-of-scope errors into warnings. + Using a value that depends on an out-of-scope variable produces a runtime error, + the same as :ghc-flag:`-fdefer-type-errors` (which implies this option). + See :ref:`typed-holes`. + + Implied by :ghc-flag:`-fdefer-type-errors`. See also :ghc-flag:`-Wdeferred-out-of-scope-variables`. + + At runtime, whenever a term containing a type error would need to be evaluated, the error is converted into a runtime exception of type ``TypeError``. Note that type errors are deferred as much as possible |