* provided, an empty map is returned defensively so that [toTypeArgumentsMapping] doesn't conjure any error types. If you want to map
     * too few type arguments meaningfully, please provide filler types explicitly.
     */
    private fun toTypeArgumentsMapping(
        typeArguments: List<FirTypeProjection>,
        partiallyAppliedSymbol: KtPartiallyAppliedSymbol<*, *>
    ): Map<KtTypeParameterSymbol, KtType> {

                    else -> Unclassified
                }
            }
        }
    }

    /**
     * Returns whether this [FirScope] is a scope wider than [another] based on the above [PartialOrderOfScope] or not.
     */
    private fun FirScope.isWiderThan(another: FirScope): Boolean =
        toPartialOrder().scopeDistanceLevel > another.toPartialOrder().scopeDistanceLevel