Example of fail

Author: 0xInnominatus

contracts/ERC20.sol

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.23;
+
+contract ERC20 {
+    string public name;
+    string public symbol;
+    uint8 public constant decimals = 18;
+
+    uint256 public totalSupply;
+    mapping(address => uint256) public balanceOf;
+    mapping(address => mapping(address => uint256)) public allowance;
+
+    event Transfer(address indexed from, address indexed to, uint256 value);
+    event Approval(address indexed owner, address indexed spender, uint256 value);
+
+    constructor(string memory _name, string memory _symbol, uint256 _initialSupply) {
+        name = _name;
+        symbol = _symbol;
+        _mint(msg.sender, _initialSupply);
+    }
+
+    function transfer(address to, uint256 amount) external returns (bool) {
+        _transfer(msg.sender, to, amount);
+        return true;
+    }
+
+    function approve(address spender, uint256 amount) external returns (bool) {
+        allowance[msg.sender][spender] = amount;
+        emit Approval(msg.sender, spender, amount);
+        return true;
+    }
+
+    function transferFrom(address from, address to, uint256 amount) external returns (bool) {
+        uint256 allowed = allowance[from][msg.sender];
+        require(allowed >= amount, "ERC20: insufficient allowance");
+        unchecked {
+            allowance[from][msg.sender] = allowed - amount;
+        }
+        _transfer(from, to, amount);
+        return true;
+    }
+
+    function _transfer(address from, address to, uint256 amount) internal {
+        require(to != address(0), "ERC20: transfer to zero");
+        uint256 fromBalance = balanceOf[from];
+        require(fromBalance >= amount, "ERC20: insufficient balance");
+        unchecked {
+            balanceOf[from] = fromBalance - amount;
+            balanceOf[to] += amount;
+        }
+        emit Transfer(from, to, amount);
+    }
+
+    function _mint(address to, uint256 amount) internal {
+        require(to != address(0), "ERC20: mint to zero");
+        totalSupply += amount;
+        balanceOf[to] += amount;
+        emit Transfer(address(0), to, amount);
+    }
+}

contracts/Example.sol

@@ -1,11 +1,14 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.23;
 
+import { ERC20 } from "./ERC20.sol";
+
 contract Example
 {
-	address public weth;
-	constructor(address _weth)
+	string public name;
+
+	constructor(ERC20 token)
 	{
-		weth = _weth;
+		name = token.name();
 	}
 }