[Clang][Module] Transitive importation as in [module.import]/7 is not fully implemented #84002
Description
Looks like Clang does transitive import as in [module.import]/7 only when the U is "implicitly imported ([module.unit]/8)".
Basically, I expect transitive import to work when dealing with module partitions. Right now, this program doesn't compile:
The primary module interface unit:
export module test;
import std;
export import :part_interface;
import :part_impl;
export void testMIU();Module impl unit (the non-importable/not-a-partition one)
module test;
// OK, implicitly imports the primary module interface unit,
// and transitively imports std as expected
void testMIU() { std::println("testMIU"); }A partition:
export module test:part_interface;
import std;
export void testPartition();Another partition:
module test:part_impl;
import :part_interface; // should transitively import std!!
// import std; // <============ should NOT be needed
void testPartition() {
std::println("testPartition");
}