rspec/rspec-expectations — pull request #247 by tomykaira (2013-05-09 14:01:35+00:00)
Title: Warn when raise_error receives non-proc object

When a non-proc object is given, `given_proc.call` fails, then `raise_error`
or
`raise_error(NoMethodError)` passes.

This behaviour is dangerous and there is actually no error, so it should warn
and fail.