Behavior of F# “unmanaged” type constraint

Question

F# supports a type constraint for \"unmanaged\". This is not the same as a value type constraint like \"struct\" constraints. MSDN notes that the behavior of the unmanaged

Answer 1

The CorGenericParamAttr Enumeration in CorHdr.h lists all possible constraint flags at CIL level, so an unmanaged constraint is purely enforced by the F# compiler.

typedef enum CorGenericParamAttr {
    gpVarianceMask                     =   0x0003,
    gpNonVariant                       =   0x0000, 
    gpCovariant                        =   0x0001,
    gpContravariant                    =   0x0002,

    gpSpecialConstraintMask            =   0x001C,
    gpNoSpecialConstraint              =   0x0000,
    gpReferenceTypeConstraint          =   0x0004, 
    gpNotNullableValueTypeConstraint   =   0x0008,
    gpDefaultConstructorConstraint     =   0x0010
} CorGenericParamAttr;