RFR 8199910: Compiler crashes with -g option and variables of intersection type inferred by `var`

[Maurizio Cimadamore]

Attached is my take on the problem.

As I said, we added some logic to handle this with multi-catch, but 
unfortunately the current logic only handle cases where you have a type 
like A & B and not cases where you have Foo<A & B>.

I've enhanced the check to do a proper non-denotable visit on the type 
of the local variable, rather than just doing a simple check as before.

Let me know what you think - and also if you'd like me to go ahead with 
it, or if you still want to take this.

Cheers
Maurizio


On 21/03/18 16:09, Maurizio Cimadamore wrote:
>
> Hi Shinya,
> thanks for the fix; unfortunately, I believe it is not correct. An 
> intersection type should be erased by the time we get here; we had a 
> similar issue in the past with multicatch:
>
> https://bugs.openjdk.java.net/browse/JDK-6999635
>
> https://bugs.openjdk.java.net/browse/JDK-7005371
>
> I will take a closer look as to find out exactly what's going on; the 
> fix for multicatch should have taken care for this one too...
>
> Maurizio
>
>
> On 21/03/18 02:53, ShinyaYoshida wrote:
>> Hi all and Kishida,
>>
>> Thank you for reporting the issue.
>>
>> I've filed and created a patch:
>> Bugs: https://bugs.openjdk.java.net/browse/JDK-8199910
>> Webrev: http://cr.openjdk.java.net/~shinyafox/8199910/webrev/ 
>> <http://cr.openjdk.java.net/%7Eshinyafox/8199910/webrev/>
>>
>> Could someone review this?
>>
>> If it's fine, I'll commit to jdk repo and I'd like to backport to 
>> jdk10 after backport approval.
>>
>> Regards,
>> shinyafox(Shinya Yoshida)
>>
>> 2018-03-21 10:54 GMT+09:00 kishida naoki <naokikishida at gmail.com 
>> <mailto:naokikishida at gmail.com>>:
>>
>>     Hi all!
>>
>>     I'm glad that JDK 10 is released.
>>     But I've faced a compiler bug with `var`.
>>     I'm using the build 46.
>>
>>     This code crashes the compiler with `-g` option.
>>     ```
>>     public class Main {
>>         void m() {
>>             var s = java.util.List.of("a", 1);
>>         }
>>     }
>>     ```
>>
>>     $ javac Main.java -g
>>     C:\src>javac Main.java -g
>>     java.lang.AssertionError: Unexpected intersection type:
>>     java.lang.Object&java.io
>>     <http://java.io>.Serializable&java.lang.Comparable<? extends
>>     java.lang.Object&java.io
>>     <http://java.io>.Serializable&java.lang.Comparable<?>>
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter.enterInner(ClassWriter.java:1043)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter$CWSignatureGenerator.classReference(ClassWriter.java:312)
>>             at
>>     jdk.compiler/com.sun.tools.javac.code.Types$SignatureGenerator.assembleClassSig(Types.java:5182)
>>             at
>>     jdk.compiler/com.sun.tools.javac.code.Types$SignatureGenerator.assembleSig(Types.java:5114)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter$CWSignatureGenerator.assembleSig(ClassWriter.java:291)
>>             at
>>     jdk.compiler/com.sun.tools.javac.code.Types$SignatureGenerator.assembleSig(Types.java:5225)
>>             at
>>     jdk.compiler/com.sun.tools.javac.code.Types$SignatureGenerator.assembleClassSig(Types.java:5201)
>>             at
>>     jdk.compiler/com.sun.tools.javac.code.Types$SignatureGenerator.assembleSig(Types.java:5114)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter$CWSignatureGenerator.assembleSig(ClassWriter.java:291)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter.typeSig(ClassWriter.java:334)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter.writeCode(ClassWriter.java:1271)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter.writeMethod(ClassWriter.java:1158)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter.writeMethods(ClassWriter.java:1653)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter.writeClassFile(ClassWriter.java:1761)
>>             at
>>     jdk.compiler/com.sun.tools.javac.jvm.ClassWriter.writeClass(ClassWriter.java:1679)
>>             at
>>     jdk.compiler/com.sun.tools.javac.main.JavaCompiler.genCode(JavaCompiler.java:749)
>>             at
>>     jdk.compiler/com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1627)
>>             at
>>     jdk.compiler/com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1595)
>>             at
>>     jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:965)
>>             at
>>     jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:306)
>>             at
>>     jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:165)
>>             at
>>     jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:57)
>>             at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:43)
>>
>>     The cause is about intersection. The variable type that is
>>     infered becomes as a type with intersection, and will crash the
>>     compiler when generating a debug info.
>>     These are no problem.
>>       var s=List.of("a");
>>       var s=List.of("a", 1, Optional.empty());
>>       var s=List.of("a", 1, List.of());
>>
>>     Best regards.
>>
>>     -- 
>>     Naoki Kishida
>>
>>
>

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