Impact: verification stops with an internal error. It blocks 1 of the 48 real-code examples we built (bugs mined from open-source Java).

Description

A Java 21 type pattern in a switch stops verification inside Spoon (PartialSourcePosition only contains a CompilationUnit). A switch over strings with yield passes.

Minimal reproducer

public class Repro {
    static String kind(Object o) {
        return switch (o) {
            case String s -> "string " + s;
            default -> "other";
        };
    }
}

Expected

Correct! Passed Verification.

Actual

Exception in thread "main" java.lang.UnsupportedOperationException: PartialSourcePosition only contains a CompilationUnit

Reproduced on main at 0472025 (liquidjava-verifier 0.0.35); also on fbfb4e2 and 0.0.33 in the original form.

Context

Found while turning bugs mined from real open-source Java (fixed upstream or still present) into study examples for the error-message study.