c# - DynamicMethod and type checks -

can explain or point explanation why runtime types check not occurs in sample below - string property can set type value ...
stuck in unexpected place , surprised

using system; using system.reflection; using system.reflection.emit;  namespace dynamics { internal class program     {     private static void main(string[] args)     {         var = new a();         a.name = "name";         console.writeline(a.name.gettype().name);          propertyinfo pi = a.gettype().getproperty("name");                    dynamicmethod method = new dynamicmethod(                 "dynamicsetvalue", // name                 null, // return type                 new type[]                              {                                 typeof(object), // 0, objsource                                 typeof(object), // 1, value                             }, // parameter types                 typeof(program), // owner                 true); // skip visibility          ilgenerator gen = method.getilgenerator();         gen.emit(opcodes.ldarg_0);         gen.emit(opcodes.ldarg_1);         gen.emit(opcodes.call, pi.getsetmethod(true));         gen.emit(opcodes.ret);          setvalue setmethod = (setvalue)method.createdelegate(typeof(setvalue));          int val = 123;         setmethod(a, val);         console.writeline(a.name.gettype().name);          anothera = new a();         anothera.name = "another a";         setmethod(a, anothera);         console.writeline(a.name.gettype().name);     } }  public class {     public string name { get; set; } }  public delegate void setvalue(object obj, object val); } 

i did little experiment: added method class:

    static void setvalue1(a a, object v)     {         a.name = (string)v;     } 

doing setvalue1(a, 123); throws invalidcastexception of course. disassembled code using ildasm.exe. setvalue1 looks this:

.method private hidebysig static void  setvalue1(class consoleapplication2.a a,                                                    object v) cil managed   {     // code size       15 (0xf)     .maxstack  8     il_0000:  nop     il_0001:  ldarg.0     il_0002:  ldarg.1     il_0003:  castclass  [mscorlib]system.string // <--- replace nop     il_0008:  callvirt   instance void consoleapplication2.a::set_name(string)     il_000d:  nop     il_000e:  ret   } // end of method program::setvalue1 

ok, let's replace cast castclass [mscorlib]system.string nop , recompile ilasm.exe.

now call setvalue1 wrong type argument passes , produces same result dynamic method. seem clr not doing type checking in case. documentation says:

during just-in-time (jit) compilation, optional verification process examines metadata , microsoft intermediate language (msil) of method jit-compiled native machine code verify type safe. process skipped if code has permission bypass verification.

in case, running code on local machine, clr trusts il valid.

you can manually verify assembyl running peverify.exe on output .exe file. return error: program::setvalue1][offset 0x00000004][found ref 'system.object'][expected ref 'system.string'] unexpected type on stack.

there post explores topic: http://www.pcreview.co.uk/forums/net-type-safety-and-net-configuration-tool-t1225543.html