Checks for branches in if blocks with equivalent conditions.
This is most likely a copy and paste error.
if foo then
print(1)
elseif foo then
print(1)
end
This ignores conditions that could have side effects, such as function calls. This will not lint:
if foo() then
print(1)
elseif foo() then
print(1)
end
...as the result of foo()
could be different the second time it is called.