Java sequence prefix < fail compilation when combined with if ... then ... else

[Dilan-s]

Dafny version

4.1.0

Code to produce this issue

method Main() returns ()
{
    var v_seq_9: seq<int> := [];
    print [] < (if false then v_seq_9 else []);
}

Command to run and resulting output

$ dafny /compile:4 /compileTarget:java test.dfy 

_System/__default.java:14: error: method isProperPrefixOf in class DafnySequence<T> cannot be applied to given types;
    System.out.print(java.lang.String.valueOf((dafny.DafnySequence.<java.math.BigInteger> empty(dafny.TypeDescriptor.BIG_INTEGER)).isProperPrefixOf(((false) ? (_0_v__seq__9) : (dafny.DafnySequence.<java.math.BigInteger> empty(dafny.TypeDescriptor.BIG_INTEGER))))));
                                                                                                                                  ^
  required: DafnySequence<U>
  found: (false) ? [...]GER))
  reason: inference variable U has incompatible equality constraints BigInteger,CAP#1
  where U,T are type-variables:
    U extends Object declared in method <U>isProperPrefixOf(DafnySequence<U>)
    T extends Object declared in class DafnySequence
  where CAP#1 is a fresh type-variable:
    CAP#1 extends BigInteger from capture of ? extends BigInteger
1 error
Error while compiling Java files. Process exited with exit code 1

What happened?

Introducing the if then else condition as the second argument to the '<' operator for sequences causes compilation to Java to crash due to an incompatible type error.

Note that removing the if then else condition and replacing with just '[]' does not cause a crash

What type of operating system are you experiencing the problem on?

Linux