anchor.diff:  ==== Misc.
   
   * Regarding group sequences and default group sequences, the same rules apply for type argument constraints as they apply for regular element-level constraints.
  -* For the conversion of validation groups the same rules apply no matter whether `@Valid` is given for a regular element or for a type argument. I.e. the following group conversion declaration is valid:
  +* For the conversion of validation groups the same rules apply no matter whether `@Valid` is given for a regular element or for a type argument.
  +I.e. the following group conversion declaration is valid:
   
   [source,java]
   ----
  
positive.code: private CachableValue<@Min(1) Integer> foo;
  ----
  
  Validation of `foo` will fail, as none of the two matching extractors is more specific than the other one. An extractor for `CachableValue` must be added, resolving the ambiguity.
  
  ==== XML based configuration
  
  
negative.code: }
  ----
  
  The `@ExtractedValue` annotation must be specified exactly once for a value extractor type.
  Thus the following extractor definition is illegal as it specifies `@ExtractedValue` several times:
  
  [source,java]
  ----
  public class DoubleExtractor implements ValueExtractor<Multimap<@ExtractedValue ?, @ExtractedValue ?>> { ... }
  ----
  
  When defined for a generic type, only wildcard type arguments may be annotated with `@ExtractedValue`.
  I.e. the following extractor definition is illegal:
  
  [source,java]
  ----
  