Function combineUnionThisParam

test/fixtures/snapshot/typescript.js:58182–58191

(left, right, mapper)

            return true;
        }
        function combineUnionThisParam(left, right, mapper) {
            if (!left || !right) {
                return left || right;
            }
            // A signature `this` type might be a read or a write position... It's very possible that it should be invariant
            // and we should refuse to merge signatures if there are `this` types and they do not match. However, so as to be
            // permissive when calling, for now, we'll intersect the `this` types just like we do for param types in union signatures.
            var thisType = getIntersectionType([getTypeOfSymbol(left), instantiateType(getTypeOfSymbol(right), mapper)]);
            return createSymbolWithType(left, thisType);
        }
        function combineUnionParameters(left, right, mapper) {
            var leftCount = getParameterCount(left);
            var rightCount = getParameterCount(right);