This issue is reported when a function parameter is a) passed by value and b) is not modified inside the function. Instead, parameter can be passed by const reference, i.e. converted to a const& so that no unnecessary copy is created at the callsite of the function.
For example,
#include <vector>
int read_first(const std::vector<int>& vec) { return vec[0]; }
void const_refable(std::vector<int> vec) {
int first = read_first(vec); // vec is never modified, so the parameter should have type const&
}
Reported as "Dict Missing Key" by pulse.
+This issue is similar to UNINITIALIZED_VALUE issue, but it is to warn
+reading a missing key of dictionary in Hack.
For example, in the following code, the dictionary $d has no entry for bye, so reading
+$d['bye'] will throw the OutOfBoundsException exception, which is usually unexpected from
+developers. We can use a safer function idx instead when keys of a dictionary is unclear.
function simple_bad() : int {
$d = dict['hi' => 42, 'hello' => 52];
return $d['bye'];
}
Reported as "Read-only Shared Parameter" by pulse.
This issue is reported when a shared pointer parameter is a) passed by value and b) is used only for reading, rather than lifetime extension. At the callsite, this might cause a potentially expensive unnecessary copy of the shared pointer, especially when many number of threads are sharing it. To avoid this, consider 1) passing the raw pointer instead and 2) use std::shared_ptr::get at callsites.
weakSelf with self:
[self foo:^() {
[self bar];
}];
Limitations: To keep this check simple and intra-procedural, we rely on names to find weakSelf:
-we assume that any captured weak pointer whose name contains "self" is a weak reference to self.
self.