swift

e7d7f6f6 - RequirementMachine: Add Copyable/Escapable requirements to 'placeholder' generic signatures

RequirementMachine: Add Copyable/Escapable requirements to 'placeholder' generic signatures If we fail to build a generic signature (or requirement signature of a protocol) because of a request cycle or because Knuth-Bendix completion failed, we would create a placeholder signature with no requirements. However in a move-only world, a completely unconstrained generic parameter might generate spurious diagnostics when used in a copyable way. For this reason, let's outfit these placeholder signatures with a default set of conformance requirements to Copyable and Escapable.