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maddi-java-openjdk: type-use annotations dropped from a nested class's field typed by the enclosing generic class

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#145 1 comentario 0 reacciones 0 asignados Ver en GitHub

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Nadie ha tomado este issue todavía.

Evaluación

Dificultad
4/5
Tiempo estimado
3-5 días
Aptitud para principiantes
42/100
Tipo de issue
Error
Claridad
Bastante claro
Estado de actividad
Activo
Stack tecnológico
java, kotlin
Área
compilers, devtools, testing-qa

Línea de trabajo

Start with the reduced case exercised through JavaInspectorImpl as TestNullabilityPass, then trace how nested-class field types are represented in FieldInfo.type(). Compare the enclosing-class, nested-library-type, and enclosing-generic-type cases, and inspect where ParameterizedType type-use annotations are copied or lost. Done means AS<@Nullable Object> retains the annotation for the nested Holder field and the Kotlin translation no longer produces the nullability mismatch.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

bug front-end:javac

In a static nested class, a field whose type is the enclosing generic class loses the type-use annotations on its type arguments. guava's Ordering:

public abstract class Ordering<T> implements Comparator<T> {
  private static final class ArbitraryOrderingHolder {
    static final Ordering<@Nullable Object> ARBITRARY_ORDERING = new ArbitraryOrdering();
  }
  ...
}

ARBITRARY_ORDERING's FieldInfo.type() arrives as Ordering<Object>, and the type argument's annotations() is empty.

Reduced, through JavaInspectorImpl as TestNullabilityPass in maddi-mod runs it:

package a.b;
import java.util.Comparator;
@java.lang.annotation.Target(java.lang.annotation.ElementType.TYPE_USE) @interface Nullable {}
abstract class AS<T> implements Comparator<T> {
    static final AS<@Nullable Object> ARBITRARY = new Arbitrary();   // AS<@Nullable Object>  (kept)
    static AS<@Nullable Object> plain;                               // AS<@Nullable Object>  (kept)
    private static final class Holder {
        static final AS<@Nullable Object> ARBITRARY = new Arbitrary(); // AS<Object>          (dropped)
    }
    static class Arbitrary extends AS<@Nullable Object> {
        public int compare(@Nullable Object a, @Nullable Object b) { return 0; }
    }
}

The same annotation is kept on:

  • a field of the outer class itself;
  • a field of the nested class typed by a library class, e.g. Comparator<@Nullable Object> in Holder.

The annotation is not needed on the @interface either: a top-level annotation type and one nested in AS give the same result.

Effect: the Kotlin translation prints internal val ARBITRARY_ORDERING: Ordering<Any> = ArbitraryOrdering(), while arbitrary(): Ordering<Any?> returns it. kotlinc reports "type mismatch: expected Ordering<Any?>, actual Ordering" (guava Ordering.kt:214).

Expected: the field's ParameterizedType carries the type-use annotations as written, as it does for the outer class's own fields.

Found while reducing guava's KotlinConf scoreboard compile errors, together with the printer session. Related: #144 (anonymous class creation types).

🤖 Generated with Claude Code

Lenguaje dominante
Java
Estrellas
1
Forks
1
Merge medio
1 h 58 min
PR fusionados (30 d)
5

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