[ nice-Bugs-1113263 ] java.lang.VerifyError

Bugs item #1113263, was opened at 2005-01-31 17:22
Message generated for change (Comment added) made by bonniot
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=112788&aid=1113263&group_id=12788

Category: None
Group: None
>Status: Closed
>Resolution: Fixed
Priority: 2
Submitted By: Artem Gr Kozarezov (artemgr)
>Assigned to: Arjan Boeijink (arjanb)
Summary: java.lang.VerifyError

Initial Comment:
See attached files for details.
"nice-bug.src.zip" have test case sources.
"nice-bug.bin.zip" have both sources and compiled classes.


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>Comment By: Daniel Bonniot (bonniot)
Date: 2005-02-12 15:28

Message:
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user_id=88952

I'm closing this report, as the bug reported (the
verification error) is fixed. There is still a valid
discussion as to what the semantics of assert false should
be, but this is a different matter, so it does not really
make sense to keep this bug report open. If you feel like
it, a discussion on nice-info would be appropriate, as it
would allow other people to participate.

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Comment By: Artem Gr Kozarezov (artemgr)
Date: 2005-02-07 16:08

Message:
Logged In: YES 
user_id=289741

A shorter test case:

class AssertCaseFail {
  void?->void _aFirstPointer = null;
  void?->void _aSecondPointer = null;
  void aMethod(){
    let void->void fun;
    let first = _aFirstPointer; let second = _aSecondPointer;
    if( null != first ) fun = first;
    else if( null != second ) fun = second;
    else assert false;
    fun();
  }
}

void main( String[] ) = ( new AssertCaseFail() ).aMethod();

When compiled with nicec "build 2005.02.07" (assertions are
NOT enabled):
Exception in thread "main" nice.lang.AssertionFailed
        at letfun.c.fun.aMethod(c.nice:11)
        at letfun.c.AssertCaseFail.aMethod(c.nice)
        at letfun.c.fun.main(c.nice:16)
        at letfun.c.dispatch.main(dispatch.nice)

When compiled with nicec "build 2004.09.22":
Exception in thread "main" java.lang.VerifyError: (class:
letfun/c/fun, method: aMethod signature:
(Lletfun/c/AssertCaseFail;
)V) Register 1 contains wrong type
        at letfun.c.dispatch.main(dispatch.nice)

Expected behaviour is to give a compile-time error about
"fun" being used without being initialized. But the Nice
compiler currently thinks that "assert false" will always
exit from the method, which is wrong when assertions are not
enabled.

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Comment By: Arjan Boeijink (arjanb)
Date: 2005-02-02 00:09

Message:
Logged In: YES 
user_id=688815

The problem is the code generation of 'assert false' where the 
bytecode verifier can't always know code after that is 
unreachable.

I commited a workaround for the codegeneration.

Code being unreachable after 'assert false' is different 
behaviour than Java and might be unexpected when 
assertions disabled.
http://java.sun.com/j2se/1.4.2/docs/guide/lang/assert.html

Daniel, what's your opinion on this?

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=112788&aid=1113263&group_id=12788


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