javac throws an AssertionError while compiling a switch on types

[Jan Lahoda]

Thanks for the report, Remi.


I believe the specification currently allows this (default does not have 
to be last, and does not dominate anything), so javac should be able to 
handle this code. I've filled:

https://bugs.openjdk.java.net/browse/JDK-8268333


Jan


On 07. 06. 21 11:54, Remi Forax wrote:
> Hi all,
> javac does like this code, there is a check missing because javac should not reach Gen with a code like this.
>
>      Object o = null;
>      var value = switch(o) {
>            default -> 0;
>            case String s -> 0;
>      };
>      System.out.println(value);
>
> An exception has occurred in the compiler (17-internal). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.
> java.lang.AssertionError
> 	at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:155)
> 	at jdk.compiler/com.sun.tools.javac.util.Assert.check(Assert.java:46)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.handleSwitch(Gen.java:1310)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.doHandleSwitchExpression(Gen.java:1238)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.visitSwitchExpression(Gen.java:1202)
> 	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCSwitchExpression.accept(JCTree.java:1381)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genExpr(Gen.java:877)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.visitLetExpr(Gen.java:2376)
> 	at jdk.compiler/com.sun.tools.javac.tree.JCTree$LetExpr.accept(JCTree.java:3288)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genExpr(Gen.java:877)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.visitVarDef(Gen.java:1081)
> 	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCVariableDecl.accept(JCTree.java:1028)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genDef(Gen.java:610)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genStat(Gen.java:645)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genStat(Gen.java:631)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genStats(Gen.java:682)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.visitBlock(Gen.java:1097)
> 	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1092)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genDef(Gen.java:610)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genStat(Gen.java:645)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genMethod(Gen.java:967)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.visitMethodDef(Gen.java:930)
> 	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:922)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genDef(Gen.java:610)
> 	at jdk.compiler/com.sun.tools.javac.jvm.Gen.genClass(Gen.java:2415)
> 	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.genCode(JavaCompiler.java:737)
> 	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1617)
> 	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1585)
> 	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:946)
> 	at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:317)
> 	at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:176)
> 	at jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:64)
> 	at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:50)
>
> regards,
> Rémi