5. Names and scope

Built-in names (§12) may be used in every module. Imported names and top-level names may cover them.
A top-level name may be used anywhere in its module (§2.5).
A local name may be used from the next statement to the end of its block. When the value of its binding is a direct value, it may also be used inside the function bodies in that value (§6.10). The names of a parameter group, and of a service pattern, may be used in the guard and the body of their branch. ( ) makes no scope: the items of data are worked out in the scope around it, and a label is not a name.
A type parameter of a function (§4.7) may be used in that function, or in the rest of that function type. A type parameter of a type definition may be used in that definition (§4.3). An alias pattern has no type parameters; its binders are types of the module.
A local name may cover an outer name with the same name, and an earlier binding in the same block.
A discard makes no name.