Template variable does not exist

A variable was configured in a VAR_CONFIG block, but the variable can not be found in the code.

Erroneous code example:

VAR_CONFIG
    main.foo.bar AT %IX1.0 : BOOL;
END_VAR

PROGRAM main
    VAR
        foo : foo_fb;
    END_VAR
END_PROGRAM

FUNCTION_BLOCK foo_fb
    VAR
        qux AT %I* : BOOL;
    END_VAR
END_FUNCTION_BLOCK

In this example a variable named bar is configured, however the function block foo_fb does not contain a bar variable. The could should have been main.foo.qux AT %IX1.0 : BOOL instead for it to be valid.