IR codegen does not implement access to library address by contract name

[cameel]

Discovered in #15661 (comment)

Description

A reference to a library name in inline assembly triggers an unimplemented feature error. At this point the IR codegen is considered feature-complete so this not being implemented yet is a bug.

Moreover the error does not provide any message for the user.

While we do have this case covered by a syntax test (assignment_from_library.sol), it went undiscovered until now because we don't run syntax tests via IR. When the bug is fixed, please remember to enable this test on EOF.

Environment

• Compiler version: 0.8.28 (develop)

Steps to Reproduce

test.sol:

library L {}

contract C {
    function f() public pure {
        assembly {
            let x := L
        }
    }
}

solc test.sol --ir

Error: Unimplemented feature
 --> test.sol:5:9:
  |
5 |         assembly {
  |         ^ (Relevant source part starts here and spans across multiple lines).