pub fn merge_fn_types(types: &[DataType]) -> Option<DataType>Expand description
The one function type that holds every type in types, where more than one
function can land in the same position.
A position every function in it agrees on stays pinned to that function, so
a list of one closure and a call through it resolve at compile time exactly
as they did. Two different functions make the position a function value: no
function is the one it holds, so the call dispatches on what the value
carries. None where the types name no function, which leaves the position
to the ordinary rules.