This annotated GLib/C code fragment:

/**
 * Returns: (element-type GLib.Value) the value
 */
 GPtrArray * get_values (Foo *src) {}

ends up with this .gir fragment for its return type:

<array name="GLib.PtrArray" c:type="GPtrArray*">
    <type name="GLib.Value"/>
</array>

which maps to the C type "GValue*[]" (and Vala type "GLib.Value[]").

However, the real return type is "GLib.PtrArray of GLib.Value elements" (Vala type GLib.PtrArray<GLib.Value>).

So my proposal is that the g-i scanner instead generate this GIR fragment from the annotated code above:

<type name="GLib.PtrArray" c:type="GPtrArray*">
    <type name="GLib.Value" c:type="GValue*"/>
</type>

For types that truly are primitive arrays, the element-type will correspond to the C type. Eg,

/**
 * Returns: (element-type GLib.Value) the value
 */
 GValue ** get_values_primitive_array (Foo *src) {}

which should result in the GIR fragment

<array name="GLib.Value" c:type="GValue*"></array>