Function inferTypeArguments

test/fixtures/snapshot/typescript.js:75470–75541

(node, signature, args, checkMode, context)

                    thisArgumentType;
        }
        function inferTypeArguments(node, signature, args, checkMode, context) {
            if (ts.isJsxOpeningLikeElement(node)) {
                return inferJsxTypeArguments(node, signature, checkMode, context);
            }
            // If a contextual type is available, infer from that type to the return type of the call expression. For
            // example, given a 'function wrap<T, U>(cb: (x: T) => U): (x: T) => U' and a call expression
            // 'let f: (x: string) => number = wrap(s => s.length)', we infer from the declared type of 'f' to the
            // return type of 'wrap'.
            if (node.kind !== 165 /* SyntaxKind.Decorator */) {
                var contextualType = getContextualType(node, ts.every(signature.typeParameters, function (p) { return !!getDefaultFromTypeParameter(p); }) ? 8 /* ContextFlags.SkipBindingPatterns */ : 0 /* ContextFlags.None */);
                if (contextualType) {
                    var inferenceTargetType = getReturnTypeOfSignature(signature);
                    if (couldContainTypeVariables(inferenceTargetType)) {
                        // We clone the inference context to avoid disturbing a resolution in progress for an
                        // outer call expression. Effectively we just want a snapshot of whatever has been
                        // inferred for any outer call expression so far.
                        var outerContext = getInferenceContext(node);
                        var outerMapper = getMapperFromContext(cloneInferenceContext(outerContext, 1 /* InferenceFlags.NoDefault */));
                        var instantiatedType = instantiateType(contextualType, outerMapper);
                        // If the contextual type is a generic function type with a single call signature, we
                        // instantiate the type with its own type parameters and type arguments. This ensures that
                        // the type parameters are not erased to type any during type inference such that they can
                        // be inferred as actual types from the contextual type. For example:
                        //   declare function arrayMap<T, U>(f: (x: T) => U): (a: T[]) => U[];
                        //   const boxElements: <A>(a: A[]) => { value: A }[] = arrayMap(value => ({ value }));
                        // Above, the type of the 'value' parameter is inferred to be 'A'.
                        var contextualSignature = getSingleCallSignature(instantiatedType);
                        var inferenceSourceType = contextualSignature && contextualSignature.typeParameters ?
                            getOrCreateTypeFromSignature(getSignatureInstantiationWithoutFillingInTypeArguments(contextualSignature, contextualSignature.typeParameters)) :
                            instantiatedType;
                        // Inferences made from return types have lower priority than all other inferences.
                        inferTypes(context.inferences, inferenceSourceType, inferenceTargetType, 128 /* InferencePriority.ReturnType */);
                        // Create a type mapper for instantiating generic contextual types using the inferences made
                        // from the return type. We need a separate inference pass here because (a) instantiation of
                        // the source type uses the outer context's return mapper (which excludes inferences made from
                        // outer arguments), and (b) we don't want any further inferences going into this context.
                        var returnContext = createInferenceContext(signature.typeParameters, signature, context.flags);
                        var returnSourceType = instantiateType(contextualType, outerContext && outerContext.returnMapper);
                        inferTypes(returnContext.inferences, returnSourceType, inferenceTargetType);
                        context.returnMapper = ts.some(returnContext.inferences, hasInferenceCandidates) ? getMapperFromContext(cloneInferredPartOfContext(returnContext)) : undefined;
                    }
                }
            }
            var restType = getNonArrayRestType(signature);
            var argCount = restType ? Math.min(getParameterCount(signature) - 1, args.length) : args.length;
            if (restType && restType.flags & 262144 /* TypeFlags.TypeParameter */) {
                var info = ts.find(context.inferences, function (info) { return info.typeParameter === restType; });
                if (info) {
                    info.impliedArity = ts.findIndex(args, isSpreadArgument, argCount) < 0 ? args.length - argCount : undefined;
                }
            }
            var thisType = getThisTypeOfSignature(signature);
            if (thisType && couldContainTypeVariables(thisType)) {
                var thisArgumentNode = getThisArgumentOfCall(node);
                inferTypes(context.inferences, getThisArgumentType(thisArgumentNode), thisType);
            }
            for (var i = 0; i < argCount; i++) {
                var arg = args[i];