FULL PRODUCT VERSION :
java version "1.8.0_152"
Java(TM) SE Runtime Environment (build 1.8.0_152-b16)
Java HotSpot(TM) 64-Bit Server VM (build 25.152-b16, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Linux d0074211 4.13.11 #1 SMP Thu Nov 2 22:32:48 CET 2017 x86_64 GNU/Linux

EXTRA RELEVANT SYSTEM CONFIGURATION :
Verified the bug on multiple OSes (Linux, OS X, Windows) and JDK 8.x and 9.x versions

A DESCRIPTION OF THE PROBLEM :
Consider this simple class:

public class SomeClass<T> {
    public <@A1 S extends @A2 T> @A3 S myMethod() { ...}
}

@A2 annotation on the bound T is inaccessible via reflection. See below for details.
 
Assuming myMethod is SomeClass.class.getDeclaredMethod("myMethod"). Type casts removed for readability.

myMethod.getGenericReturnType().getAnnotations() - returns @A1 (expected)
myMethod.getGenericReturnType().getBounds()[0].getAnnotations() - returns nothing (no declaration annotation on T)
myMethod.getAnnotatedReturnType().getAnnotations() - returns @A3 (expected)
myMethod.getAnnotatedReturnType().getAnnotatedBounds()[0].getAnnotations() - returns @A2

See https://stackoverflow.com/questions/47175573/how-to-get-type-use-annotations-on-a-generic-bound for a better formatted description, discussion and analysis

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Create a generic class containing a method with an annotated bounded type variable as the return type.
E.g.
public class SomeClass<T> {
    public <@A1 S extends @A2 T> @A3 S myMethod() { ...}
}

2. Try retrieving the @A2 annotation via reflection:
Method myMethod = SomeClass.class.getDeclaredMethod("myMethod");
Annotation[] annotations = myMethod.getGenericReturnType().getBounds()[0].getAnnotations(); // declaration annotation on T
Annotation[] annotations2 = myMethod.getAnnotatedReturnType().getAnnotatedBounds()[0].getAnnotations(); // type use annotation on T's use as upper(extends) bound


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
At least one of the annotation arrays from above (annotations and annotations2) should contain the @A2 instance
ACTUAL -
Both methods return no annotations

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package io.leangen.graphql.jimmy;

import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.AnnotatedTypeVariable;
import java.lang.reflect.Method;
import java.lang.reflect.TypeVariable;

public class AnnotatedBoundTest {

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.TYPE_USE)
    @interface A1 {
    }

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.TYPE_USE)
    @interface A2 {
    }

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.TYPE_USE)
    @interface A3 {
    }

    public class SomeClass<T> {
        <@A1 S extends @A2 T> @A3 S myMethod() { return null;}
    }


    public static void main(String[] args) throws NoSuchMethodException {
        Method myMethod = SomeClass.class.getDeclaredMethod("myMethod");
        Annotation[] annotations = ((TypeVariable) ((TypeVariable) myMethod.getGenericReturnType()).getBounds()[0]).getAnnotations();
        Annotation[] annotations2 = ((AnnotatedTypeVariable) myMethod.getAnnotatedReturnType()).getAnnotatedBounds()[0].getAnnotations();
        assert annotations.length == 1; // fails, no declaration annotation on T
        assert annotations2.length == 1; // succeeds
    }
}

---------- END SOURCE ----------