The function preprocessor is broken. The line numbers are incorrect.
It's because no #LINE directive is added for the define (#LINE 1 "PATH\define.hpp). Instead, the start of the script is put right after the define (#LINE 1 "PATH\fn_someFnc.sqf")
See the steps to reproduce and additional details.
preprocessorFileLineNumbers works fine.
Create a function in description.ext. Put this EXACT code in it (it contains errors but it's for testing):
#include "defines.hpp" //line2 //line3 //line4 "This should be line 5" BUT ITS LINE10
contents of defines.hpp:
#define A 1 #define B 2 #define C 2 #define D 2 #define E 2
This is the contents of the test function after preprocessing:
{
private _fnc_scriptNameParent = if (isNil '_fnc_scriptName') then {'TEST_fnc_TEST'} else {_fnc_scriptName};
private _fnc_scriptName = 'TEST_fnc_TEST';
scriptName _fnc_scriptName;
#line 1 "TEST\fn_TEST.sqf [TEST_fnc_TEST]"
"This should be line 5" BUT ITS LINE10}