#Using a custom Solidity compiler

To use a custom, local version of the Solidity compiler, you need to override the TASK_COMPILE_SOLIDITY_GET_SOLC_BUILD subtask in your Hardhat config.

This subtask returns an object with four properties:

compilerPath: the path to the compiler
isSolcJs: a flag indicating if the compiler is a javascript module or a native binary
version: the short version of the compiler (for example, 0.8.24)
longVersion: the long version of the compiler (for example, 0.8.24+commit.e11b9ed9). This property is used as extra metadata in the build-info files, so you shouldn't worry too much about its value.

Here is an example to override the wasm solc build for version 0.8.24. Before proceeding, ensure you download the required solc binary to the root of your hardhat project.

TypeScript

JavaScript

// hardhat.config.js
import { HardhatUserConfig, subtask } from "hardhat/config";

const {
  TASK_COMPILE_SOLIDITY_GET_SOLC_BUILD,
} = require("hardhat/builtin-tasks/task-names");
const path = require("path");

subtask(
  TASK_COMPILE_SOLIDITY_GET_SOLC_BUILD,
  async (
    args: {
      solcVersion: string;
    },
    hre,
    runSuper
  ) => {
    if (args.solcVersion === "0.8.24") {
      const compilerPath = path.join(
        __dirname,
        "soljson-v0.8.24+commit.e11b9ed9.js"
      );

      return {
        compilerPath,
        isSolcJs: true, // if you are using a native compiler, set this to false
        version: args.solcVersion,
        // This is used as extra information in the build-info files,
        // but other than that is not important
        longVersion: "0.8.24+commit.e11b9ed9",
      };
    }

    // since we only want to override the compiler for version 0.8.24,
    // the runSuper function allows us to call the default subtask.
    return runSuper();
  }
);

const config: HardhatUserConfig = {
  solidity: "0.8.24",
};

export default config;

// hardhat.config.js
const {
  TASK_COMPILE_SOLIDITY_GET_SOLC_BUILD,
} = require("hardhat/builtin-tasks/task-names");
const path = require("path");

subtask(TASK_COMPILE_SOLIDITY_GET_SOLC_BUILD, async (args, hre, runSuper) => {
  if (args.solcVersion === "0.8.24") {
    const compilerPath = path.join(
      __dirname,
      "soljson-v0.8.24+commit.e11b9ed9.js"
    );

    return {
      compilerPath,
      isSolcJs: true, // if you are using a native compiler, set this to false
      version: args.solcVersion,
      // This is used as extra information in the build-info files,
      // but other than that is not important
      longVersion: "0.8.24+commit.e11b9ed9",
    };
  }

  // since we only want to override the compiler for version 0.8.24,
  // the runSuper function allows us to call the default subtask.
  return runSuper();
});

module.exports = {
  solidity: "0.8.24",
};

Check our "Creating a task" guide to learn more about overriding tasks.