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Diffstat (limited to 'docs/users_guide/ghci.rst')
| -rw-r--r-- | docs/users_guide/ghci.rst | 29 |
1 files changed, 6 insertions, 23 deletions
diff --git a/docs/users_guide/ghci.rst b/docs/users_guide/ghci.rst index d5a2083eab..92dc51e00f 100644 --- a/docs/users_guide/ghci.rst +++ b/docs/users_guide/ghci.rst @@ -2951,37 +2951,20 @@ commonly used commands. .. ghci-cmd:: :type; ⟨expression⟩ - Infers and prints the type of ⟨expression⟩, including explicit - forall quantifiers for polymorphic types. - The type reported is the type that would be inferred - for a variable assigned to the expression, but without the - monomorphism restriction applied. + Infers and prints the type of ⟨expression⟩. For polymorphic types + it instantiates the 'inferred' forall quantifiers (but not the + 'specified' ones; see :ref:`inferred-vs-specified`), solves constraints, and re-generalises. .. code-block:: none *X> :type length length :: Foldable t => t a -> Int -.. ghci-cmd:: :type +v; ⟨expression⟩ - - Infers and prints the type of ⟨expression⟩, but without fiddling - with type variables or class constraints. This is useful when you - are using :extension:`TypeApplications` and care about the distinction - between specified type variables (available for type application) - and inferred type variables (not available). This mode sometimes prints - constraints (such as ``Show Int``) that could readily be solved, but - solving these constraints may affect the type variables, so GHC refrains. - - .. code-block:: none - - *X> :set -fprint-explicit-foralls - *X> :type +v length - length :: forall (t :: * -> *). Foldable t => forall a. t a -> Int - .. ghci-cmd:: :type +d; ⟨expression⟩ - Infers and prints the type of ⟨expression⟩, defaulting type variables - if possible. In this mode, if the inferred type is constrained by + Infers and prints the type of ⟨expression⟩, instantiating *all* the forall + quantifiers, solving constraints, defaulting, and generalising. + In this mode, if the inferred type is constrained by any interactive class (``Num``, ``Show``, ``Eq``, ``Ord``, ``Foldable``, or ``Traversable``), the constrained type variable(s) are defaulted according to the rules described under :extension:`ExtendedDefaultRules`. |