Inheritance and EnhancedFor

[Andrea Poli]

Hi, I tried to analyze this piece of code usign RECODER:

Collection<Integer> numbers = new ArrayList<Integer>();
        numbers.add((Integer) num);

        this.numbers = new int[numbers.size()];
        int c = 0;
        for (Number n : numbers) {          
            this.numbers[c++] = n.intValue();
        }

I got the following error:

+++ Error: TypingException - lhs does not match rhs - java.lang.Number :
java.util.Collection<java.lang.Integer> - exp: numbers - 35/25 - - -
recoder.service.SemanticsChecker$SemanticsCheckerVisitor.visitEnhancedFor(Sema
nticsChecker.java:163)
recoder.java.statement.EnhancedFor.accept(EnhancedFor.java:117)
recoder.service.SemanticsChecker.check(SemanticsChecker.java:105)
recoder.service.SemanticsChecker.checkAllCompilationUnits(SemanticsChecker.jav
a:92)
...

(Error occurred outside a model update)

I started to debug the code and it seems that Number isn't a supertype of
Integer according to:

public boolean isSubtype(ClassType a, ClassType b)

method of class recoder.service.DefaultProgramModelInfo. During the debug
parameter a value was Number type and parameter b value was Integer type.

I tried to add this piece of code at line 546 of the above method:

}else if (b.getSupertypes().contains(a)){
            return true;
        }

After this change Number is recognized as a supertype of Integer but it isn't
the right way to do it because it makes other typing errors appear.

Thanks a lot :-)

[Andrea Poli]

I think the problem is the call to isWidening inside
recoder.service.SemanticsChecker at line 156, visitEnhancedFor method.

                        if (si.isWidening(lhsType, ct)) {
                                foundProperType = true;
                            break;
                        }

It seems that it checks if lhsType (initializer) is a subtype of ct (guard)
but it should check if ct is a subtype of lhsType.

                        if (si.isWidening(ct, lhsType)) {
                                foundProperType = true;
                            break;
                        }

[Tobias Gutzmann]

Correct. It's a bug. Please use the bug tracker for those :)
Fixed in SVN / next release.