private String typeBuilderSimpleName() {
		boolean isOutside = isOutsideBuilder();
		Naming typeBuilderNaming = names().namings.typeBuilder;
		if (isOutside) {
			// For outer builder we can override with constant builder naming, but not the default.
			boolean isPlainDefault =
					isConstantNamingEquals(typeBuilderNaming, protoclass().environment().defaultStyles().typeBuilder());

			if (isPlainDefault) {
				typeBuilderNaming = typeBuilderNaming.requireNonConstant(Preference.SUFFIX);
			}
		}

		return Naming.Usage.CAPITALIZED.apply(typeBuilderNaming.apply(names().raw));
	}
Walks to the enclosing type's simple names and applies naming convention.
This shortcut/fix shows deficiency of model (it's probably more complicated than needed).
@return enclosing immutable name
value-processor/src/org/immutables/value/processor/meta/Constitution.java