VerifyError in switch expression on double

[aumann]

This code compiles, but fails at runtime:

package test;
public class SwitchVerifyError {

  public static void main(String[] args) {
    double d = 3;

    double r = switch (d) {
      case 1.0 -> 0.2;
      case 2.0 -> 0.5;
      case 8.0 -> 2;
      case 9.0 -> 3;
      default -> 3;
    };
    System.out.println(r);
  }

}

The error is:

Fehler: Hauptklasse test.SwitchVerifyError kann nicht initialisiert werden
Ursache: java.lang.VerifyError: Bad type on operand stack
Exception Details:
  Location:
    test/SwitchVerifyError.main([Ljava/lang/String;)V @5: tableswitch
  Reason:
    Type double_2nd (current frame, stack[1]) is not assignable to integer
  Current Frame:
    bci: @5
    flags: { }
    locals: { '[Ljava/lang/String;', double, double_2nd }
    stack: { double, double_2nd }
  Bytecode:
    0000000: 1400 1048 27aa 0000 0000 004b 0000 0001
    0000010: 0000 0009 0000 0033 0000 0039 0000 004b
    0000020: 0000 004b 0000 004b 0000 004b 0000 004b
    0000030: 0000 003f 0000 0045 1400 12a7 0018 1400
    0000040: 14a7 0012 1400 16a7 000c 1400 10a7 0006
    0000050: 1400 104a b200 1829 b600 1eb1          
  Stackmap Table:
    append_frame(@56,Double)
    same_frame(@62)
    same_frame(@68)
    same_frame(@74)
    same_frame(@80)
    same_locals_1_stack_item_frame(@83,Double)

The JDT versions according to my eclipse installation details are: 3.37.0.v20240215-1452 org.eclipse.jdt.core and 3.19.400.v20240229-0520 org.eclipse.jdt

I do not know if the bug is that it compiles at all, or that it fails at runtime...

[iloveeclipse]

I can reproduce on latest master, where I also see a new warning attached to main method:
Internal inconsistency: Inappropriate operand stack size encountered during translation
I assume this is one of the cases that @srikanth-sankaran is already working on.

[srikanth-sankaran]

I'll follow up.

[srikanth-sankaran]

This code is not supposed to compile in the first place.

14.11 states:

The switch statement transfers control to one of several statements or expressions,
depending on the value of an expression.
SwitchStatement:
switch ( Expression ) SwitchBlock
The Expression is called the selector expression. The type of the selector expression
must be char, byte, short, int, or a reference type, or a compile-time error occurs.

JDK21 rejects with (I renamed the class to be X.java)

X.java:7: error: constant label of type double is not compatible with switch selector type double
      case 1.0 -> 0.2;
           ^
X.java:8: error: constant label of type double is not compatible with switch selector type double
      case 2.0 -> 0.5;
           ^
X.java:9: error: constant label of type double is not compatible with switch selector type double
      case 8.0 -> 2;
           ^
X.java:10: error: constant label of type double is not compatible with switch selector type double
      case 9.0 -> 3;
           ^
4 errors

which is weird.

JDK22 rejects it with:

X.java:6: error: selector type double is not allowed
    double r = switch (d) {
                      ^
1 error

which is bang on.

[srikanth-sankaran]

On master, we reject the code correctly for language levels <=20. The verify error is encountered for levels JDK21 and JDK22 (only)