c# - Is the Null-Conditional operator optimized across consecutive usages sites or does it result in duplicate checks? -

does using null-conditional operator duplicate null checks? example

var x = instance?.property1; var y = instance?.property2; 

does compiled this:

if (instance != null) {   var x = instance.property1;   var y = instance.property2; } 

or this?

if (instance != null) {   var x = instance.property1; }  if (instance != null) {   var y = instance.property2; } 

if former, make difference if there other code in between both lines? in other words, how smart compiler/optimizer?

the compiler appears quite ignorant of this.

the code:

var x = instance?.property1; var y = instance?.property2; 

...compiles non-optimized to:

il_0000:  nop          il_0001:  newobj      userquery+class..ctor il_0006:  stloc.0     // instance il_0007:  ldloc.0     // instance il_0008:  brtrue.s    il_000d il_000a:  ldnull       il_000b:  br.s        il_0013 il_000d:  ldloc.0     // instance il_000e:  ldfld       userquery+class.property1 il_0013:  stloc.1     // x il_0014:  ldloc.0     // instance il_0015:  brtrue.s    il_001a il_0017:  ldnull       il_0018:  br.s        il_0020 il_001a:  ldloc.0     // instance il_001b:  ldfld       userquery+class.property2 il_0020:  stloc.2     // y il_0021:  ret           class..ctor: il_0000:  ldarg.0      il_0001:  call        system.object..ctor il_0006:  nop          il_0007:  ret          

...and optimized as:

il_0000:  newobj      userquery+class..ctor il_0005:  dup          il_0006:  dup          il_0007:  brtrue.s    il_000c il_0009:  pop          il_000a:  br.s        il_0012 il_000c:  ldfld       userquery+class.property1 il_0011:  pop          il_0012:  dup          il_0013:  brtrue.s    il_0017 il_0015:  pop          il_0016:  ret          il_0017:  ldfld       userquery+class.property2 il_001c:  pop          il_001d:  ret           class..ctor: il_0000:  ldarg.0      il_0001:  call        system.object..ctor il_0006:  ret          

both 2 branch checks.