Added link between freeze --lock and --reject-unconstrained-dependencies

Author: LaurentRDC

changelog.d/pr-10785.md

@@ -6,3 +6,5 @@ issues: 10784
 ---
 
 Added a `--lock` flag to `cabal freeze`, to promote a freeze file to a lock file. By calling `cabal freeze --lock`, the resulting freeze file will ensure that only dependencies whose constraints are specified, will be accepted by future build plans. This flag can be used to ensure that no unaudited packages are added to the build plan.
+
+This new `--lock` flag reuses the mechanism behind `--reject-unconstrained-dependencies`, by writing the equivalent of `--reject-unconstrained-dependencies=all` to the freeze file.

doc/cabal-commands.rst

@@ -538,6 +538,9 @@ a freeze file is not, by default, a **lockfile**. To turn a freeze file into a l
 use the ``--lock`` flag when invocating ``cabal freeze``. This will prevent future
 builds from including new dependencies. This can be helpful in situations where
 every dependency must be explicitly audited and approved, for example.
+Under the hood, the ``--lock`` flag reuses the mechanism behind 
+``--reject-unconstrained-dependencies``, by writing the equivalent of 
+``--reject-unconstrained-dependencies=all`` to the freeze file.
 
 cabal gen-bounds
 ^^^^^^^^^^^^^^^^