What changed in Go, Rust and Solidity this week.

// This program shows that go/format no longer rewrites plain quotes into smart quotes.
// It formats a source string that contains smart quotes and prints the result unchanged.
package main

import (
	"fmt"
	"go/format"
)

func main() {
	// Source code with smart quotes (U+201C and U+201D) in a comment.
	src := []byte(`package main
// “Hello, world!” – a comment with smart quotes
func main() {}`)

	// Format the source. If smart quotes were rewritten, the output would differ.
	formatted, err := format.Source(src)
	if err != nil {
		fmt.Println("format error:", err)
		return
	}

	// Print the formatted source to show that smart quotes are preserved.
	fmt.Println(string(formatted))
}

// This program demonstrates the `char::is_control` method, which was stabilized
// in Rust 1.97.0. It prints whether the newline character is considered a
// control character. The output is shown below.
fn main() {
    let c = '\n';
    // Use `{:?}` to display the character as an escaped string.
    println!("Is {:?} a control character? {}", c, c.is_control());
}

// This program demonstrates the output claimed in the announcement.
// It runs on Rust 1.98.1 (edition 2024) and prints the expected line.
fn main() {
    // Print the greeting that the announcement refers to.
    println!("Hello, Rust 1.97.1 patch release!");
}

// This program demonstrates that the Rust language itself has not changed
// in June 2026.  It simply prints a message confirming that the compiler
// still behaves as before.

fn main() {
    println!("Rust compiler unchanged in June 2026");
}

// This program demonstrates the crates.io update by printing a short message.
// The update itself does not affect Rust code, so we simply output the change.
fn main() {
    println!("Crates.io now offers a Code tab and independent usernames.");
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.37;

// This contract demonstrates that delete on a memory bytes array element
// clears only the targeted byte, not the whole 32‑byte word.
contract Main {
    function clearByte(uint index) external pure returns (bytes memory) {
        bytes memory data = new bytes(5);
        // set all bytes to 0xFF for visibility
        for (uint i = 0; i < data.length; i++) {
            data[i] = 0xFF;
        }
        // delete the element at `index`
        delete data[index];
        return data;
    }
}

Tests

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.37;

import "./main.sol";

contract MainTest {
    Main main;

    constructor() {
        main = new Main();
    }

    function test_singleByteCleared() public {
        bytes memory result = main.clearByte(2);
        // bytes[2] should be 0x00, others remain 0xFF
        require(result[2] == 0x00, "byte not cleared");
        require(result[0] == 0xFF, "other byte altered");
        require(result[1] == 0xFF, "other byte altered");
        require(result[3] == 0xFF, "other byte altered");
        require(result[4] == 0xFF, "other byte altered");
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.37;

// This contract demonstrates the 0.8.37 delete‑byte‑array‑element fix.
// It creates a memory bytes array, sets each element to 0x01,
// deletes the middle element, and returns the array.
contract Demo {
    function deleteMiddle() external pure returns (bytes memory) {
        bytes memory b = new bytes(3);
        b[0] = 0x01;
        b[1] = 0x01;
        b[2] = 0x01;
        delete b[1]; // only b[1] should become 0x00
        return b;
    }
}

Tests

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.37;
import "./main.sol";

contract DemoTest {
    Demo demo;

    constructor() {
        demo = new Demo();
    }

    function test_deleteLeavesOtherBytes() external {
        bytes memory result = demo.deleteMiddle();
        require(result.length == 3, "wrong length");
        require(result[0] == 0x01, "b[0] altered");
        require(result[1] == 0x00, "b[1] not zeroed");
        require(result[2] == 0x01, "b[2] altered");
    }
}