Crate name, along with its disambiguator (128-bit hash) represents a globally
unique crate identifier, which should allow for differentiation between
different crate targets or versions and should point to the same crate when
pulled by different other, dependent crates.
A common identifier for definitions, references etc. This is effectively a
DefId
with globally unique crate number (instead of a compiler generated
crate-local number).
An identifier (either a reference or definition).
SymbolQuery
specifies the preficate for filtering symbols by name.