Merge branch 'master' into dev-scope

Author: montyly

README.md

@@ -218,5 +218,6 @@ Slither is licensed and distributed under the AGPLv3 license. [Contact us](mailt
 - [Verification of Ethereum Smart Contracts: A Model Checking Approach](http://www.ijmlc.org/vol10/977-AM0059.pdf), Tam Bang, Hoang H Nguyen, Dung Nguyen, Toan Trieu, Tho Quan - IJMLC 20
 - [Smart Contract Repair](https://arxiv.org/pdf/1912.05823.pdf), Xiao Liang Yu, Omar Al-Bataineh, David Lo, Abhik Roychoudhury - TOSEM 20
 - [Demystifying Loops in Smart Contracts](https://www.microsoft.com/en-us/research/uploads/prod/2020/08/loops_solidity__camera_ready-5f3fec3f15c69.pdf), Ben Mariano, Yanju Chen, Yu Feng, Shuvendu Lahiri, Isil Dillig - ASE 20
+- [Trace-Based Dynamic Gas Estimation of Loops in Smart Contracts](https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9268144), Chunmiao Li, Shijie Nie, Yang Cao, Yijun Yu, Zhenjiang Hu -  IEEE Open J. Comput. Soc. 1 (2020)
 
 If you are using Slither on an academic work, consider applying to the [Crytic $10k Research Prize](https://blog.trailofbits.com/2019/11/13/announcing-the-crytic-10k-research-prize/).

slither/core/declarations/solidity_variables.py

@@ -25,6 +25,7 @@
     "block.number": "uint256",
     "block.timestamp": "uint256",
     "block.blockhash": "uint256",  # alias for blockhash. It's a call
+    "block.chainid": "uint256",
     "msg.data": "bytes",
     "msg.gas": "uint256",
     "msg.sender": "address",