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Diffstat (limited to 'docs/users_guide/exts/instances.rst')
| -rw-r--r-- | docs/users_guide/exts/instances.rst | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/docs/users_guide/exts/instances.rst b/docs/users_guide/exts/instances.rst index 1af795ca03..3dd7969d97 100644 --- a/docs/users_guide/exts/instances.rst +++ b/docs/users_guide/exts/instances.rst @@ -6,7 +6,7 @@ Instance declarations and resolution An instance declaration has the form :: - instance ( assertion1, ..., assertionn) => class type1 ... typem where ... + instance (assertion1, ..., assertionn) => class type1 ... typem where ... The part before the "``=>``" is the *context*, while the part after the "``=>``" is the *head* of the instance declaration. @@ -74,7 +74,7 @@ GHC relaxes this rule in two ways: writing the RHS of the type synonym definition. For example: :: type Point a = (a,a) - instance C (Point a) where ... + instance C (Point a) where ... is legal. The instance declaration is equivalent to :: @@ -382,7 +382,7 @@ like this: target constraint is a substitution instance of :math:`I`. These instance declarations are the *candidates*. -- If no candidates remain, the search failes +- If no candidates remain, the search fails - Eliminate any candidate :math:`IX` for which there is another candidate :math:`IY` such that both of the following hold: @@ -450,7 +450,7 @@ former is a substitution instance of the latter. For example (D) is "more specific" than (C) because you can get from (C) to (D) by substituting ``a := Int``. -The final bullet (about unifiying instances) +The final bullet (about unifying instances) makes GHC conservative about committing to an overlapping instance. For example: :: |