quarkusio/quarkus · error · IllegalArgumentException

Missing type argument mapping for ${type}

Error message

Missing type argument mapping for ${type}

What it means

IllegalArgumentException from JandexUtil.mapGenerics: while re-mapping a generic type through the current type-argument mapping, a type variable has no entry in the mapping — the declared generics context does not bind that type variable. The unmapped type is appended to the message.

Source

Thrown at independent-projects/resteasy-reactive/common/processor/src/main/java/org/jboss/resteasy/reactive/common/processor/JandexUtil.java:302

    private static Type mapGenerics(Type type, Map<String, Type> mapping) {
        switch (type.kind()) {
            case ARRAY:
                ArrayType arrayType = type.asArrayType();
                return ArrayType.create(mapGenerics(arrayType.constituent(), mapping), arrayType.dimensions());
            case CLASS:
                return type;
            case PARAMETERIZED_TYPE:
                ParameterizedType parameterizedType = type.asParameterizedType();
                Type owner = null;
                if (parameterizedType.owner() != null) {
                    owner = mapGenerics(parameterizedType.owner(), mapping);
                }
                return ParameterizedType.create(parameterizedType.name(),
                        mapGenerics(parameterizedType.arguments(), mapping).toArray(new Type[0]), owner);
            case TYPE_VARIABLE:
                Type ret = mapping.get(type.asTypeVariable().identifier());
                if (ret == null) {
                    throw new IllegalArgumentException("Missing type argument mapping for " + type);
                }
                return ret;
            default:
                throw new IllegalArgumentException("Illegal type in hierarchy: " + type);
        }
    }

    private static ClassInfo fetchFromIndex(DotName dotName, IndexView index) {
        final ClassInfo classInfo = index.getClassByName(dotName);
        if (classInfo == null) {
            throw new IllegalArgumentException("Class " + dotName + " was not found in the index");
        }
        return classInfo;
    }

    /**
     * Returns the enclosing class of the given annotation instance. For field, method or record component annotations,
     * this will return the enclosing class. For parameters, this will return the enclosing class of the enclosing

View on GitHub (pinned to e1c734241f)

Solutions

1. Ensure the generic type is used in a context that binds all its type variables (no raw or partially-parameterized supertypes)
2. Simplify the generics of the affected resource/response type

When it happens

Trigger: Thrown at independent-projects/resteasy-reactive/common/processor/src/main/java/org/jboss/resteasy/reactive/common/processor/JandexUtil.java:302 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/fe03124c12f244b7. Report an issue: GitHub.