.net - C# Compiler - Unassigned DateTime Field and Local Variable -

out of curiosity:

this code valid , executes:

public class program {     private static datetime date;      public static void main()     {         console.writeline(date.tostring("o"));     } } 

see working on .net fiddle

but doesn´t compile (unassigned local variable):

public class program {     public static void main()     {         datetime date;         console.writeline(date.tostring("o"));     } } 

see (not) working on .net fiddle

datetime non nullable value type, doesn´t need assigned , initialized have value, has default one.

so why compiler allows datetime field version compile , doesn´t let local variable version compile? when code compiled il, prevents value type local variable being used?

a field has no explicit initialisation automatically initialised default value.

this useful it's common initial value, saves time.

a local has no initialisation in state can not used.

this useful because did wrong (especially if there several paths determine initial value), setting default hide bug.