Undefined variable error but variable is indeed defined

//_variable.scss
$blue-base: #66ccff;
$blue-dark: darken($blue-base, 10%);
$blue: $blue-base;
$blue-light: lighten($blue-base, 10%);
$blue-lighter: lighten($blue-base, 20%);
$blue-lightest: lighten($blue-base, 25%);

$link-color: $blue-dark;
$link-some-active-color: $blue;

// _global.scss
a {
    color: $link-color;
    text-decoration: none;

    &:hover, &:active, &:focus {
        color: $link-some-active-color;
    }
}

Error:

events.js:141
      throw er; // Unhandled 'error' event
      ^
Error: src/sass/_global.scss
Error: Undefined variable: "$link-some-active-color".
        on line 20 of src/sass/_global.scss
>>         color: $link-some-active-color;
   ---------------^

I am using Gulp.

[majidzeno]

@manix I faced the same issue with Sass, in my case the error was because I included the variables file after the other file where I used them, you could try doing this, reorder files import, make the variables file at the top.

[manix]

@guoyunhe can you elaborate?