This note explains the difference in type inference between single expression and
non-single expression closures. It is associated with the "unable to infer
complex closure return type" diagnostic.
Educational notes are small pieces of documentation which explain a concept
relevant to some diagnostic message. If -enable-descriptive-diagnostics is
passed, they will be printed after a diagnostic message if available.
Educational notes can be found at /usr/share/doc/diagnostics in a
toolchain, and are associated with specific compiler diagnostics in
EducationalNotes.def.
