Convert a D type to a type the backend understands.
Convert front end type t to backend type t.ctype. Memoize the result.
Determine backend tym bits corresponding to MOD
See Source File _toctype.d Documentation: https://dlang.org/phobos/dmd_toctype.html Coverage: https://codecov.io/gh/dlang/dmd/src/master/src/dmd/toctype.d
Walter Bright
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Boost License 1.0
Convert a D type to a type the backend understands.