Function inferFromObjectTypes

test/fixtures/snapshot/typescript.js:68936–69029

(source, target)

                }
            }
            function inferFromObjectTypes(source, target) {
                if (ts.getObjectFlags(source) & 4 /* ObjectFlags.Reference */ && ts.getObjectFlags(target) & 4 /* ObjectFlags.Reference */ && (source.target === target.target || isArrayType(source) && isArrayType(target))) {
                    // If source and target are references to the same generic type, infer from type arguments
                    inferFromTypeArguments(getTypeArguments(source), getTypeArguments(target), getVariances(source.target));
                    return;
                }
                if (isGenericMappedType(source) && isGenericMappedType(target)) {
                    // The source and target types are generic types { [P in S]: X } and { [P in T]: Y }, so we infer
                    // from S to T and from X to Y.
                    inferFromTypes(getConstraintTypeFromMappedType(source), getConstraintTypeFromMappedType(target));
                    inferFromTypes(getTemplateTypeFromMappedType(source), getTemplateTypeFromMappedType(target));
                    var sourceNameType = getNameTypeFromMappedType(source);
                    var targetNameType = getNameTypeFromMappedType(target);
                    if (sourceNameType && targetNameType)
                        inferFromTypes(sourceNameType, targetNameType);
                }
                if (ts.getObjectFlags(target) & 32 /* ObjectFlags.Mapped */ && !target.declaration.nameType) {
                    var constraintType = getConstraintTypeFromMappedType(target);
                    if (inferToMappedType(source, target, constraintType)) {
                        return;
                    }
                }
                // Infer from the members of source and target only if the two types are possibly related
                if (!typesDefinitelyUnrelated(source, target)) {
                    if (isArrayOrTupleType(source)) {
                        if (isTupleType(target)) {
                            var sourceArity = getTypeReferenceArity(source);
                            var targetArity = getTypeReferenceArity(target);
                            var elementTypes = getTypeArguments(target);
                            var elementFlags = target.target.elementFlags;
                            // When source and target are tuple types with the same structure (fixed, variadic, and rest are matched
                            // to the same kind in each position), simply infer between the element types.
                            if (isTupleType(source) && isTupleTypeStructureMatching(source, target)) {
                                for (var i = 0; i < targetArity; i++) {
                                    inferFromTypes(getTypeArguments(source)[i], elementTypes[i]);
                                }
                                return;
                            }
                            var startLength = isTupleType(source) ? Math.min(source.target.fixedLength, target.target.fixedLength) : 0;
                            var endLength = Math.min(isTupleType(source) ? getEndElementCount(source.target, 3 /* ElementFlags.Fixed */) : 0, target.target.hasRestElement ? getEndElementCount(target.target, 3 /* ElementFlags.Fixed */) : 0);
                            // Infer between starting fixed elements.
                            for (var i = 0; i < startLength; i++) {
                                inferFromTypes(getTypeArguments(source)[i], elementTypes[i]);
                            }
                            if (!isTupleType(source) || sourceArity - startLength - endLength === 1 && source.target.elementFlags[startLength] & 4 /* ElementFlags.Rest */) {
                                // Single rest element remains in source, infer from that to every element in target
                                var restType = getTypeArguments(source)[startLength];
                                for (var i = startLength; i < targetArity - endLength; i++) {
                                    inferFromTypes(elementFlags[i] & 8 /* ElementFlags.Variadic */ ? createArrayType(restType) : restType, elementTypes[i]);
                                }
                            }
                            else {
                                var middleLength = targetArity - startLength - endLength;
                                if (middleLength === 2 && elementFlags[startLength] & elementFlags[startLength + 1] & 8 /* ElementFlags.Variadic */ && isTupleType(source)) {
                                    // Middle of target is [...T, ...U] and source is tuple type
                                    var targetInfo = getInferenceInfoForType(elementTypes[startLength]);
                                    if (targetInfo && targetInfo.impliedArity !== undefined) {
                                        // Infer slices from source based on implied arity of T.