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Ghost variables are not correctly initialized in interfaces

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#44 1 comment 0 reactions 1 assignee View on GitHub

@pcanelas is already working on this.

Since Jul 4, 2025.

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Description

bug enhancement

Ghost variable initialization is dependent on declaring the constructor for the type the that the refinements are for. This declaration implicitly initializes int variables in a way equivalent to @StateRefinement(to = "var(this) == 0")
It is not possible to declare constructors for interface types as these don't have constructors. This prohibits the correct initialization of both Ghost variables and States for interfaces

@ExternalRefinementsFor("java.util.List")
@Ghost("int size2")
public interface ListRefinements<E> {

	@StateRefinement(to = "size2(this) == (size2(old(this)) + 1)")
	public boolean add(E elem);

	@StateRefinement(from = "size2(this) > 0", to = "size2(this) == (size2(old(this)) - 1)")
	public void remove(@Refinement("index >= 0") int index);
}
	public static void main(String[] args) {
		List<Integer> l = new ArrayList<>();

		l.add(0);

		int a = l.remove(0);
	}

The error provided is Failed to check state transitions when calling l.remove(0)

This error messages is identical to the error message that would appear when attempting the same operation on a concrete class without a declared constructor in the Refinement definitions

Dominant language
Java
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Merged PRs (30d)
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