When import is not accessed, the 'Imported file not found' diagnostic is not shown

[tempit]

:import {
-st-from: './imporxt.st.css';
-st-default: Comp;
}

.local {
-st-extends: Com;
}

Shows: cannot resolve "-st-extends" type for "Com"
But does not show error that imporxt.st.css does not exist.

[tomrav]

It should also discern between missing files, and missing symbols.