Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v0.7.0)
// ----

%extended {
  border: none;
}

%extend {
  width: 100%;
  .child {
    @extend %extended;
    padding: 10px;
  }
}

.extend {
  @extend %extend;
}

SassMeister-output.css

.extend {
  border: none; }

.extend {
  width: 100%; }
  %extend .extend {
    padding: 10px; }

Here we see the Libsass processor fail in applying the selector .extend .child to the .child element of the extended parent, %extend .extend (ln 6 ...output.css) in applied instead.

When extending another placeholder class with that child, an alternate errant selector is then passed along and applied as .extend (ln 1 ...output.css) instead of .extend .child.