Function signaturesRelatedTo

test/fixtures/snapshot/typescript.js:66608–66700

(source, target, kind, reportErrors)

                return result;
            }
            function signaturesRelatedTo(source, target, kind, reportErrors) {
                var _a, _b;
                if (relation === identityRelation) {
                    return signaturesIdenticalTo(source, target, kind);
                }
                if (target === anyFunctionType || source === anyFunctionType) {
                    return -1 /* Ternary.True */;
                }
                var sourceIsJSConstructor = source.symbol && isJSConstructor(source.symbol.valueDeclaration);
                var targetIsJSConstructor = target.symbol && isJSConstructor(target.symbol.valueDeclaration);
                var sourceSignatures = getSignaturesOfType(source, (sourceIsJSConstructor && kind === 1 /* SignatureKind.Construct */) ?
                    0 /* SignatureKind.Call */ : kind);
                var targetSignatures = getSignaturesOfType(target, (targetIsJSConstructor && kind === 1 /* SignatureKind.Construct */) ?
                    0 /* SignatureKind.Call */ : kind);
                if (kind === 1 /* SignatureKind.Construct */ && sourceSignatures.length && targetSignatures.length) {
                    var sourceIsAbstract = !!(sourceSignatures[0].flags & 4 /* SignatureFlags.Abstract */);
                    var targetIsAbstract = !!(targetSignatures[0].flags & 4 /* SignatureFlags.Abstract */);
                    if (sourceIsAbstract && !targetIsAbstract) {
                        // An abstract constructor type is not assignable to a non-abstract constructor type
                        // as it would otherwise be possible to new an abstract class. Note that the assignability
                        // check we perform for an extends clause excludes construct signatures from the target,
                        // so this check never proceeds.
                        if (reportErrors) {
                            reportError(ts.Diagnostics.Cannot_assign_an_abstract_constructor_type_to_a_non_abstract_constructor_type);
                        }
                        return 0 /* Ternary.False */;
                    }
                    if (!constructorVisibilitiesAreCompatible(sourceSignatures[0], targetSignatures[0], reportErrors)) {
                        return 0 /* Ternary.False */;
                    }
                }
                var result = -1 /* Ternary.True */;
                var incompatibleReporter = kind === 1 /* SignatureKind.Construct */ ? reportIncompatibleConstructSignatureReturn : reportIncompatibleCallSignatureReturn;
                var sourceObjectFlags = ts.getObjectFlags(source);
                var targetObjectFlags = ts.getObjectFlags(target);
                if (sourceObjectFlags & 64 /* ObjectFlags.Instantiated */ && targetObjectFlags & 64 /* ObjectFlags.Instantiated */ && source.symbol === target.symbol ||
                    sourceObjectFlags & 4 /* ObjectFlags.Reference */ && targetObjectFlags & 4 /* ObjectFlags.Reference */ && source.target === target.target) {
                    // We have instantiations of the same anonymous type (which typically will be the type of a
                    // method). Simply do a pairwise comparison of the signatures in the two signature lists instead
                    // of the much more expensive N * M comparison matrix we explore below. We erase type parameters
                    // as they are known to always be the same.
                    for (var i = 0; i < targetSignatures.length; i++) {
                        var related = signatureRelatedTo(sourceSignatures[i], targetSignatures[i], /*erase*/ true, reportErrors, incompatibleReporter(sourceSignatures[i], targetSignatures[i]));
                        if (!related) {
                            return 0 /* Ternary.False */;
                        }
                        result &= related;
                    }
                }
                else if (sourceSignatures.length === 1 && targetSignatures.length === 1) {
                    // For simple functions (functions with a single signature) we only erase type parameters for
                    // the comparable relation. Otherwise, if the source signature is generic, we instantiate it
                    // in the context of the target signature before checking the relationship. Ideally we'd do
                    // this regardless of the number of signatures, but the potential costs are prohibitive due
                    // to the quadratic nature of the logic below.
                    var eraseGenerics = relation === comparableRelation || !!compilerOptions.noStrictGenericChecks;
                    var sourceSignature = ts.first(sourceSignatures);
                    var targetSignature = ts.first(targetSignatures);