4.1.5 Function calls
Under "Static type analysis", the first sentence says "to typecheck 
a Core function call we first check in Section [7 Additional
semantics of functions] if there is a
specialized typing rule for the function."  Then the second 
sentence says "Otherwise, the function signatures matching the 
function name and arity are retrieved...".

This seems to be logically inverted.  The first sentence assumes
that you know whether a function call matches something in 
section 7, yet you have not even decided what function is being
invoked, which comes in the second sentence.  

This can be fixed by clarifying that the check of Section 7
is done purely on the basis of the function's namespace and 
name, without needing to consult its signature.  Thus the 
first sentence would be "If the namespace of the function is
either fs or fn, and if the name matches one of the functions
named in Section 7, then we use the rules in the subsection
of Section 7 for the function on the basis of its namespace 
and name."  That's probably what you meant; I think this just
expresses it more precisely.