rails/rails — pull request #17805 by fw42 (2014-11-27 20:38:19+00:00)
Title: Remove multi-assignments

Change a bunch of parallel assignments to sequential assignments, since the former perform additional array allocations that can worsen performance in hot paths.

Little example:
```ruby
require 'benchmark'

N = 10_000_000

Benchmark.bm(15) do |x|
x.report('parallel') do
N.times do
a, b = 10, 20
end
end

x.report('sequentially') do |x|
N.times do
a = 10
b = 20
end
end
end
```
```
user system total real
parallel 1.950000 0.030000 1.980000 ( 2.031743)
sequentially 1.400000 0.010000 1.410000 ( 1.497073)
```

@arthurnn @dylanahsmith, please take a look