This error in our Rails application drove me crazy. The error was like this:
undefined method xxxxxx' for #<Hash:0x000000001234>
The problem was that i was calling a method like this:
And the method definition was like
def a_method(var: var) which resulted in something called variable shadowing and caused clash between variable passed in the method and local variable being defined.
The fix was to change method definition to
Still learning Ruby.