How is null + true a string?

Question

Since true is not a string type, how is null + true a string ?

string s = true;  //Cannot implicitly convert type \'bool\' to \'string\         


        

Answer 1

null will be cast to null string, and there is implicit converter from bool to string so the true will be cast to string and then, + operator will be applied: it's like: string str = "" + true.ToString();

if you check it with Ildasm:

string str = null + true;

it's as bellow:

.locals init ([0] string str)
  IL_0000:  nop
  IL_0001:  ldc.i4.1
  IL_0002:  box        [mscorlib]System.Boolean
  IL_0007:  call       string [mscorlib]System.String::Concat(object)
  IL_000c:  stloc.0