Function mappedTypeRelatedTo

test/fixtures/snapshot/typescript.js:66188–66203

(source, target, reportErrors)

            // related to Y, where X' is an instantiation of X in which P is replaced with Q. Notice
            // that S and T are contra-variant whereas X and Y are co-variant.
            function mappedTypeRelatedTo(source, target, reportErrors) {
                var modifiersRelated = relation === comparableRelation || (relation === identityRelation ? getMappedTypeModifiers(source) === getMappedTypeModifiers(target) :
                    getCombinedMappedTypeOptionality(source) <= getCombinedMappedTypeOptionality(target));
                if (modifiersRelated) {
                    var result_10;
                    var targetConstraint = getConstraintTypeFromMappedType(target);
                    var sourceConstraint = instantiateType(getConstraintTypeFromMappedType(source), makeFunctionTypeMapper(getCombinedMappedTypeOptionality(source) < 0 ? reportUnmeasurableMarkers : reportUnreliableMarkers));
                    if (result_10 = isRelatedTo(targetConstraint, sourceConstraint, 3 /* RecursionFlags.Both */, reportErrors)) {
                        var mapper = createTypeMapper([getTypeParameterFromMappedType(source)], [getTypeParameterFromMappedType(target)]);
                        if (instantiateType(getNameTypeFromMappedType(source), mapper) === instantiateType(getNameTypeFromMappedType(target), mapper)) {
                            return result_10 & isRelatedTo(instantiateType(getTemplateTypeFromMappedType(source), mapper), getTemplateTypeFromMappedType(target), 3 /* RecursionFlags.Both */, reportErrors);
                        }
                    }
                }
                return 0 /* Ternary.False */;
            }
            function typeRelatedToDiscriminatedType(source, target) {
                // 1. Generate the combinations of discriminant properties & types 'source' can satisfy.
                //    a. If the number of combinations is above a set limit, the comparison is too complex.