local is only valid in functions.

Problematic code:

local foo=bar
echo "$foo"

Correct code:

foo=bar
echo "$foo"

Rationale:

In Bash, local can only be used in functions. In other contexts, it's an error.

Exceptions:

It's possible to source files containing local from a function context but not from any other context. This is not good practice, but in these cases you can ignore this error.