[BUG] Stack overflow in val handler

[shoaniki]

Describe the bug
Attempting to use val can cause a stack overflow within Lombok in certain cases.

In the miminal example below, the issue is an interface with a recursive generic type. The problem only arises in this specific case -- many minor changes to the code will bypass it (e.g. changing the method parameter to a raw Thing, or giving it a concrete type such as Thing<Integer>, or changing the interface type to <T extends Comparable<T>> or <T extends Comparable<?>> will all cause the code to compile successfully).

To Reproduce

import lombok.val;

public class Example {
    public void run(Thing<?> thing) {
        val x = thing;
    }
}

interface Thing<T extends Comparable<? super T>> {}

Expected behavior
Lombok infers the type of x as Thing<?>, or emits an informative error if it is unable to handle this case by design.

Version info (please complete the following information):

• Lombok version 1.18.12 (and all the earlier versions I tried, back to 1.12.2)
• Platform: javac 1.8.0_211 and javac 11.0.4-ojdkbuild

Additional context
The stack trace I get (for javac 11, Lombok 1.18.12) is:

java.lang.StackOverflowError
    at lombok.javac.JavacResolution.typeToJCTree0(JavacResolution.java:322)
    at lombok.javac.JavacResolution.typeToJCTree(JavacResolution.java:308)
    at lombok.javac.JavacResolution.typeToJCTree0(JavacResolution.java:373)
    at lombok.javac.JavacResolution.typeToJCTree(JavacResolution.java:308)
    at lombok.javac.JavacResolution.typeToJCTree0(JavacResolution.java:366)
    at lombok.javac.JavacResolution.typeToJCTree(JavacResolution.java:308)
    at lombok.javac.JavacResolution.genericsToJCTreeNodes(JavacResolution.java:412)
    at lombok.javac.JavacResolution.typeToJCTree0(JavacResolution.java:402)
    GOTO 10