Embedded statement cannot be a declaration or labeled statement

You have a statement (if or while, for example), right before the code you posted, without curly braces.

For example:

if (somethingIsTrue) 
{    
   var user= new ApplicationUser { 
       UserName = model.myUser.Email,
       Email = model.myUser.Email ,
   };
}

is correct, but the code below:

if (somethingIsTrue) 
   var user = new ApplicationUser { 
      UserName = model.myUser.Email,
      Email = model.myUser.Email ,
   };

will result in CS1023: Embedded statement cannot be a declaration or labeled statement.

UPDATE

The reason, according to @codefrenzy, is that the newly declared variable will immediately go out of scope, unless it is enclosed in a block statement, where it can be accessed from.

The compilation will pass in the following cases though.

If you only initialize a new instance of a type, without declaring a new variable:

if (somethingIsTrue) 
   new ApplicationUser { 
       UserName = model.myUser.Email,
       Email = model.myUser.Email ,
   };

or if you assign a value to an existing variable:

ApplicationUser user;

if (somethingIsTrue) 
   user = new ApplicationUser { 
       UserName = model.myUser.Email,
       Email = model.myUser.Email ,
   };