title: SASS - Bootstrap 4 - Error when trying to use 'button-size' mixin
body: <p>I'm getting an error when trying to use the <strong>button-size</strong> mixin of Bootstrap 4 (version <strong>4.3.1</strong>)</p>
  
  <p>This is the code of the mixin I'm trying to include (taken from '<em>\node_modules\bootstrap\scss\mixins\_buttons.scss</em>'):</p>
  
  <pre><code>@mixin button-size($padding-y, $padding-x, $font-size, $line-height, $border-radius) {
    padding: $padding-y $padding-x;
    @include font-size($font-size);
    line-height: $line-height;
    // Manually declare to provide an override to the browser default
    @include border-radius($border-radius, 0);
  }
  </code></pre>
  
  <p>This is a snippet of Bootstrap Sass code in the node_modules of my project where the mixin is used ('<em>\node_modules\bootstrap\scss\_buttons.scss</em>') - mixin is included at line <strong>17</strong>:</p>
  
  <pre><code>// stylelint-disable selector-no-qualifying-type
  
  //
  // Base styles
  //
  
  .btn {
    display: inline-block;
    font-family: $btn-font-family;
    font-weight: $btn-font-weight;
    color: $body-color;
    text-align: center;
    vertical-align: middle;
    user-select: none;
    background-color: transparent;
    border: $btn-border-width solid transparent;
    @include button-size($btn-padding-y, $btn-padding-x, $btn-font-size, $btn-line-height, $btn-border-radius);
    @include transition($btn-transition);
  
    @include hover {
      color: $body-color;
      text-decoration: none;
    }
  
    &amp;:focus,
    &amp;.focus {
      outline: 0;
      box-shadow: $btn-focus-box-shadow;
    }
  
    // Disabled comes first so active can properly restyle
    &amp;.disabled,
    &amp;:disabled {
      opacity: $btn-disabled-opacity;
      @include box-shadow(none);
    }
  
    &amp;:not(:disabled):not(.disabled):active,
    &amp;:not(:disabled):not(.disabled).active {
      @include box-shadow($btn-active-box-shadow);
  
      &amp;:focus {
        @include box-shadow($btn-focus-box-shadow, $btn-active-box-shadow);
      }
    }
  }
  </code></pre>
  
  <p>This is how I include the mixin in my code:</p>
  
  <pre><code>.my-btn {
    // $padding-y: 0.5rem
    // $padding-x: 0.25rem
    // $font-size: 0.875rem
    // $line-height: 1.5
    // $border-radius: 0.25rem
    @include button-size(0.5rem, 0.25rem, 0.875rem, 1.5, 0.25rem);
  }
  </code></pre>
  
  <p>This is the error I'm getting:</p>
  
  <pre><code>Failed to compile.
  
  ./src/styles.scss (./node_modules/@angular-devkit/build-angular/src/angular-cli-files/plugins/raw-css-loader.js!./node_modules/postcss-loader/src??embedded!./node_modules/sass-loader/lib/loader.js??ref--14-3!./src/styles.scss)
  Module build failed (from ./node_modules/sass-loader/lib/loader.js):
  
  undefined
            ^
        Wrong number of arguments (2 for 1) for `border-radius'
        in ***\node_modules\bootstrap\scss\mixins\_buttons.scss (line 106, column 12)
  </code></pre>
  
  <p>The error is related to the border-radius argument, but I don't understand why it sees 2 arguments when I'm passing just one.</p>