<div dir="ltr"><div class="gmail_default" style="font-family:monospace">Hello Amber Dev Team,</div><div class="gmail_default" style="font-family:monospace"><br></div><div class="gmail_default" style="font-family:monospace">When if/else statements and final variables combine, the compiler can make some helpful assertions. Consider the following code.<br></div><div style="font-family:monospace" class="gmail_default">   <br>   sealed interface SomeInterface {}<br>   record First() implements SomeInterface {}<br>   record Second() implements SomeInterface {}   <br>   <br>   private void exhaustiveIfWithFinalUninitialized()<br>   {<br>   <br>      SomeInterface abc = new First();<br>   <br>      final int numA;<br>      final int numB;<br>     <br>      if (abc instanceof First)<br>      {<br>      <br>         numA = -1;<br>         numB = -1;<br>      <br>      }<br>      <br>      else if (abc instanceof Second)<br>      {<br>      <br>         numA = -2;<br>         numB = -2;<br>      <br>      }<br>      <br>      else<br>      {<br>      <br>         throw new IllegalStateException("This shouldn't be possible!");<br>      <br>      }<br>      <br>      System.out.println(numA + "");<br>      System.out.println(numB + "");<br>      <br>   }</div><div style="font-family:monospace" class="gmail_default"><br></div><div class="gmail_default" style="font-family:monospace">The above code compiles with no errors whatsoever. The compiler is smart enough to realize that, no matter what, numA and numB will most certainly be populated by the time we reach the print statements below the if statements. <br></div><div class="gmail_default" style="font-family:monospace"><br></div><div class="gmail_default" style="font-family:monospace">However, the compiler does not make the same realization 
when working with exhaustive switches. But since the switch statement is exhaustive, shouldn't the compiler be able to make the same realization here? If anything, the switch should be capable of all of the above and more, correct? <br></div><div class="gmail_default" style="font-family:monospace">   <br>   private void exhaustiveSwitchWithFinalUninitialized()<br>   {<br>   <br>      final int numA;<br>      final int numB;<br>      <br>      SomeInterface abc = new First();<br>   <br>      switch (abc) 
//compiler error unless we uncomment the default

<br>      {<br>      <br>         case First f  -><br>         {<br>         <br>            numA = 1;<br>            numB = 0;<br>         <br>         }<br>      <br>         case Second s -> <br>         {<br>         <br>            numA = 0;<br>            numB = 1;<br>            <br>         }<br>         /*<br>         default -><br>         {<br>         <br>            numA = 2;<br>            numB = 2;<br>         <br>         }<br>         */<br>      }<br>   <br>      System.out.println(numA + "");<br>      System.out.println(numB + "");<br>   <br>   }</div><div class="gmail_default" style="font-family:monospace"><br></div><div class="gmail_default" style="font-family:monospace">I would like it if the compiler could make the same realizations it did for the if statement. I should also add, this seems to apply to all forms of exhaustive switch except for those with default clauses.</div><div class="gmail_default" style="font-family:monospace"><br></div><div class="gmail_default" style="font-family:monospace">Obviously, this is easy to work around - I could just make a switch expression for each variable, and then just populate them individually. Alternatively, I could just put a default clause any time I need that compiler realization, though I give up some benefits from exhaustive switch as a result.<br></div><div class="gmail_default" style="font-family:monospace"><br></div><div class="gmail_default" style="font-family:monospace">Thank you all for your time and help!</div><div class="gmail_default" style="font-family:monospace">David Alayachew<br></div></div>