Is a C# dynamic POD a value or reference type?

Question

Q: In the example below, is n a value or by reference?

dynamic n = (int)2;

---

By default, unless otherwise specified:

• Class instances, and Arrays, are reference types.

• POD types, and possibly structs, are value types.

Conceptually, the value above could be thought of as a "dynamic POD type", or a "dynamic type containing a POD", either way it's not obvious which of the above rules should apply, if they both apply, this could lead to a contradiction.

To me, dynamic feels as if it should behave like the value it holds, or otherwise be a reference type.

Answer 1

dynamic is same as object. Actually if you'll use decompiler (e.g. ILDasm), you will see

  object n = 2

Or if you prefer IL code

.locals init (
    [0] object
)

IL_0000: nop
IL_0001: ldc.i4.2
IL_0002: box [mscorlib]System.Int32
IL_0007: stloc.0

So n is object and it's a reference type. And yes, you have boxing here. Even C# specification says that dynamic can be considered identical to object (4.7 The dynamic type):

dynamic is considered identical to object except in the following respects:

• Operations on expressions of type dynamic can be dynamically bound (§7.2.2).

• Type inference (§7.5.2) will prefer dynamic over object if both are candidates.