Some stage (e.g, hull shaders) have arrayed builtin outputs (e.g, position).
When copying from the internal structure to the split form, it is necessary
to propagate that indirection to the actual arrayed outputs. This was not
happening.
Addresses #1181
InputPatch parameters to patch constant functions were not using the
internal (temporary) variable type. That could cause validation errors
if the input patch had a mixture of builtins and user qualified members.
This uses the entry point's internal form.
There is currently a limitation: if an InputPatch is used in a PCF,
it must also have appeared in the main entry point's parameter list.
That is not a limitation of HLSL. Currently that situation is detected
and an "implemented" error results. The limitation can be addressed,
but isn't yet in the current form of the PR.
Hull shaders have an implicitly arrayed output. This is handled by creating an arrayed form of the
provided output type, and writing to the element of it indexed by InvocationID.
The implicit indirection into that array was causing some troubles when copying to a split
structure. handleAssign was able to handle simple symbol lvalues, but not an lvalue composed
of an indirection into an array.
