Corpus-NZ/Code-Syntax-Expanded · Datasets at Hugging Face

wrong_code stringlengths 3 123	correct_code stringlengths 3 155	explanation stringclasses 101 values	language stringclasses 26 values
JOIN profiles ON items.id = profiles.age	JOIN profiles ON items.id = profiles.age	Correct.	SQL
let item: i32 = "hello";	let item: &str = "hello";	Type mismatch.	Rust
let bar = 49; bar += 1;	let mut bar = 49; bar += 1;	Need mut to modify.	Rust
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(34);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(34, () => console.log('listening'));	Add callback.	Node.js
try {{ throw 'data'; }} catch(e) {{}}	try {{ throw new Error('data'); }} catch(e) {{}}	Throw Error objects.	JavaScript
for c in range(8) print(c)	for c in range(8): print(c)	Colon after for.	Python
SELECT * FROM users WHRE id=19;	SELECT * FROM users WHERE id=19;	Fix WHERE.	SQL
assert b > 77	assert b > 77	Correct.	Python
$items[94]	if ($items.Count -gt 94) {{ $items[94] }}	Check bounds.	PowerShell
DELETE FROM users WHERE id=58	DELETE FROM users WHERE id=58;	Add semicolon.	SQL
num == '35'	num === 35	Use strict equality.	JavaScript
if c > 86 print('data')	if c > 86: print('data')	Colon missing after if.	Python
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
int values[11]; values[11]=5;	int values[11]; if(11<11){{}} else values[11]=5;	Bounds check.	C++
let str = String::from("result"); let r=&str; str.push_str("!");	let mut str = String::from("result"); let r=&str; println!("{{}}", r); str.push_str("!");	Cannot mutate while borrowed.	Rust
String x = 'world';	String x = "world";	Double quotes.	Java
with open('input.csv') as file_handle: data = file_handle.read()	with open('input.csv') as file_handle: data = file_handle.read()	Correct.	Python
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
<div color=#fff>	<div style='color:#fff;'>	Use style attribute.	CSS
<hr></hr>	<hr>	Self-closing.	HTML
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
list[44]	if list.indices.contains(44) {{ list[44] }}	Check index.	Swift
{{"value":"message",}}	{{"value":"message"}}	Remove trailing comma.	JSON
class User def method end end	class User def method end end	Correct.	Ruby
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
function process(): void {{ return 80; }}	function process(): number {{ return 80; }}	Return type mismatch.	TypeScript
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
if b = 96	if b == 96	Use ==.	Ruby
echo result data	echo 'result data'	Quote to prevent splitting.	Shell
print 'hello'	print('hello')	Parentheses for function call.	Lua
print('value')	print('value')	Correct.	R
<input type='text' value='test'>	<input type='text' value='test' name='status'>	Add name attribute.	HTML
WHERE id = '5'	WHERE id = 5	Don't quote integer.	SQL
cin >> data cout << data;	cin >> data; cout << data;	Add semicolon.	C++
<div><p>world</div></p>	<div><p>world</p></div>	Nest properly.	HTML
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
h1 {{ font-size:35px color:#333; }}	h1 {{ font-size:35px; color:#333; }}	Add semicolon.	CSS
<person age=14>	<person age="14">	Quote attribute.	XML
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
function process() {{ echo 'info'; }}	function process() {{ echo 'info'; }}	Correct.	PHP
p {{ color: red }}	p {{ color: red; }}	Add semicolon.	CSS
class Item {{ int val; }} obj.val=5;	class Item {{ public int val; }} obj.val=5;	Make field public.	Java
'message' + 11	'message' + str(11)	Can't add int to string.	Python
if (x = 96) {{}}	if (x === 96) {{}}	Use === for equality.	JavaScript
fn baz() -> i32 {{ 96 }}	fn baz() -> i32 {{ 96 }}	Correct.	Rust
let z: number = 'info';	let z: string = 'info';	Fix type.	TypeScript
let bar: Int = 'hello'	let bar: String = 'hello'	Fix type.	Swift
let c = 95; let c = 66;	let c = 95; c = 66;	Duplicate declaration.	JavaScript
function bar(count) print(count) end	function bar(count) print(count) end	Correct.	Lua
local b = 51	local b = 51	Correct.	Lua
jwt.sign({{id:66}}, 'token');	jwt.sign({{id:66}}, 'token', {{expiresIn:'7d'}});	Add expiration.	Node.js
{{'id':80, 'value' 58}}	{{'id':80, 'value':58}}	Colon missing.	Python
// comment	/* comment */	Use /* */.	CSS
int count = 'test';	String count = 'test';	Type mismatch.	Dart
<img src='test.jpg'>	<img src='test.jpg' alt='desc'>	Add alt text.	HTML
{{'title':'output'}}	{{"title":"output"}}	Use double quotes.	JSON
object Person {{ def main(args: Array[String]) = println("result") }}	object Person {{ def main(args: Array[String]): Unit = println("result") }}	Add return type Unit.	Scala
my @arr = (38,36,23);	my @arr = (38,36,23);	Correct.	Perl
baz	baz()	Add parentheses.	Kotlin
temp = result	temp = 'result'	Quote strings.	Python
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
$arr[38] = 5;	if (isset($arr[38])) $arr[38] = 5;	Check existence.	PHP
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
<br></br>	<br>	Self-closing.	HTML
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
String name = 'info';	String name = 'info';	Correct.	Dart
if ($z = 99) {{}}	if ($z -eq 99) {{}}	Use -eq.	PowerShell
else print('value')	else: print('value')	Colon after else.	Python
["output", 78]	["output", 78]	Correct.	JSON
match num {{ 1 => {{}} }}	match num {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
{ "name": "world" }	{ "name": "world" }	Correct.	JSON
let b: number \| null = null; b.toFixed(18);	let b: number \| null = null; if(b!==null) b.toFixed(18);	Null check.	TypeScript
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
const val = 71; val = 72;	let val = 71; val = 72;	Cannot reassign const.	JavaScript
if item = 10	if item == 10	Use ==.	Go
while read line; do echo $line; done < log.txt	while read line; do echo $line; done < log.txt	Correct.	Shell
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(66);	const http = require('http'); http.createServer((req,res) => res.end('output')).listen(66);	Correct.	Node.js
for i=1,19 do print(i) end	for i=1,19 do print(i) end	Correct.	Lua
if ($index = 43)	if ($index == 43)	Use ==.	Perl
bar	bar()	Add parentheses.	Swift
let str1 = String::from("info"); let text2 = str1; println!("{{}}", str1);	let str1 = String::from("info"); let text2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
status: value id: test,	status: value id: test	Remove comma.	YAML
'56' + 12	56 + 12	Avoid string coercion.	JavaScript
<p>value <b>test</p></b>	<p>value <b>test</b></p>	Nest properly.	HTML
.Product {{ color: #fff; }}	.Product {{ color: #fff; }}	Correct.	CSS
println('value')	println("value")	Double quotes.	Scala
List(20,30,15)	List(20,30,15)	Correct.	Scala
let mut x=91; let r1=&mut x; let ref2=&mut x;	let mut x=91; {{ let r1=&mut x; }} let ref2=&mut x;	Only one mutable borrow.	Rust
if [ $bar = 22 ]; then	if [ "$bar" = 22 ]; then	Quote variable.	Shell
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
print 'message'	print 'message';	Add semicolon.	Perl
for (int i=0; i<88; i++) {{}}	for (int i=0; i<88; i++) {{}}	Correct.	Java
let val = 'test'	let val = "test"	Double quotes.	Swift
int[] list = new int[54]; list[54] = 5;	int[] list = new int[54]; if (54 < list.length) list[54] = 5;	Check bounds.	Java
print 'info'	print('info')	print needs parentheses.	Python
const user:Person = {{name:'test'}};	const user:Person = {{name:'test', age:58}};	Add missing property.	TypeScript
os.sqrt(26)	import os os.sqrt(26)	Import module first.	Python
<?php // code ?>	<?php // code ?>	Correct.	PHP
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
name: hello age: 30	name: hello age: 30	Correct.	YAML

JOIN profiles ON items.id = profiles.age

Correct.

SQL

let item: i32 = "hello";

let item: &str = "hello";

Type mismatch.

Rust

let bar = 49; bar += 1;

let mut bar = 49; bar += 1;

Need mut to modify.

Rust

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(34);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(34, () => console.log('listening'));

Add callback.

Node.js

try {{ throw 'data'; }} catch(e) {{}}

try {{ throw new Error('data'); }} catch(e) {{}}

Throw Error objects.

JavaScript

for c in range(8) print(c)

for c in range(8): print(c)

Colon after for.

Python

SELECT * FROM users WHRE id=19;

SELECT * FROM users WHERE id=19;

Fix WHERE.

SQL

assert b > 77

Correct.

Python

$items[94]

if ($items.Count -gt 94) {{ $items[94] }}

Check bounds.

PowerShell

DELETE FROM users WHERE id=58

DELETE FROM users WHERE id=58;

Add semicolon.

SQL

num == '35'

num === 35

Use strict equality.

JavaScript

if c > 86 print('data')

if c > 86: print('data')

Colon missing after if.

Python

$x = 5; if ($x -eq 5) { Write-Host 'yes' }

Correct.

PowerShell

int values[11]; values[11]=5;

int values[11]; if(11<11){{}} else values[11]=5;

Bounds check.

C++

let str = String::from("result"); let r=&str; str.push_str("!");

let mut str = String::from("result"); let r=&str; println!("{{}}", r); str.push_str("!");

Cannot mutate while borrowed.

Rust

String x = 'world';

String x = "world";

Double quotes.

Java

with open('input.csv') as file_handle: data = file_handle.read()

Correct.

Python

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

Use style attribute.

CSS

<hr>

Self-closing.

HTML

int* user = nullptr; *user=5;

int* user = new int; *user=5;

Allocate memory.

C++

list[44]

if list.indices.contains(44) {{ list[44] }}

Check index.

Swift

Remove trailing comma.

JSON

class User def method end end

Correct.

Ruby

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

function process(): void {{ return 80; }}

function process(): number {{ return 80; }}

Return type mismatch.

TypeScript

public static void main(String[] args) {{}}

Correct.

Java

if b = 96

if b == 96

Use ==.

Ruby

echo result data

echo 'result data'

Quote to prevent splitting.

Shell

print 'hello'

print('hello')

Parentheses for function call.

Lua

print('value')

Correct.

R

Add name attribute.

HTML

WHERE id = '5'

WHERE id = 5

Don't quote integer.

SQL

cin >> data cout << data;

cin >> data; cout << data;

Add semicolon.

C++

<div><p>world</div></p>

<div><p>world</p></div>

Nest properly.

HTML

Add rel for security.

HTML

h1 {{ font-size:35px color:#333; }}

h1 {{ font-size:35px; color:#333; }}

Add semicolon.

CSS

Quote attribute.

XML

Correct.

XML

function process() {{ echo 'info'; }}

Correct.

PHP

p {{ color: red }}

p {{ color: red; }}

Add semicolon.

CSS

class Item {{ int val; }} obj.val=5;

class Item {{ public int val; }} obj.val=5;

Make field public.

Java

'message' + 11

'message' + str(11)

Can't add int to string.

Python

if (x = 96) {{}}

if (x === 96) {{}}

Use === for equality.

JavaScript

fn baz() -> i32 {{ 96 }}

Correct.

Rust

let z: number = 'info';

let z: string = 'info';

Fix type.

TypeScript

let bar: Int = 'hello'

let bar: String = 'hello'

Fix type.

Swift

let c = 95; let c = 66;

let c = 95; c = 66;

Duplicate declaration.

JavaScript

function bar(count) print(count) end

Correct.

Lua

local b = 51

Correct.

Lua

jwt.sign({{id:66}}, 'token');

jwt.sign({{id:66}}, 'token', {{expiresIn:'7d'}});

Add expiration.

Node.js

Colon missing.

Python

// comment

/* comment */

Use /* */.

CSS

int count = 'test';

String count = 'test';

Type mismatch.

Dart

Add alt text.

HTML

Use double quotes.

JSON

object Person {{ def main(args: Array[String]) = println("result") }}

object Person {{ def main(args: Array[String]): Unit = println("result") }}

Add return type Unit.

Scala

my @arr = (38,36,23);

Correct.

Perl

baz

baz()

Add parentheses.

Kotlin

temp = result

temp = 'result'

Quote strings.

Python

int main() {{ return 0; }}

Correct.

C++

$arr[38] = 5;

if (isset($arr[38])) $arr[38] = 5;

Check existence.

PHP

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

<br>

Self-closing.

HTML

list: - item1 - item2

Correct.

YAML

String name = 'info';

Correct.

Dart

if ($z = 99) {{}}

if ($z -eq 99) {{}}

Use -eq.

PowerShell

else print('value')

else: print('value')

Colon after else.

Python

["output", 78]

Correct.

JSON

match num {{ 1 => {{}} }}

match num {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

{ "name": "world" }

Correct.

JSON

let b: number | null = null; b.toFixed(18);

let b: number | null = null; if(b!==null) b.toFixed(18);

Null check.

TypeScript

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

const val = 71; val = 72;

let val = 71; val = 72;

Cannot reassign const.

JavaScript

if item = 10

if item == 10

Use ==.

Go

while read line; do echo $line; done < log.txt

Correct.

Shell

const http = require('http'); http.createServer((req,res) => res.end('output')).listen(66);

Correct.

Node.js

for i=1,19 do print(i) end

Correct.

Lua

if ($index = 43)

if ($index == 43)

Use ==.

Perl

bar

bar()

Add parentheses.

Swift

let str1 = String::from("info"); let text2 = str1; println!("{{}}", str1);

let str1 = String::from("info"); let text2 = str1.clone(); println!("{{}}", str1);

Clone to avoid move.

Rust

status: value id: test,

status: value id: test

Remove comma.

YAML

'56' + 12

56 + 12

Avoid string coercion.

JavaScript

<p>value <b>test</p></b>

<p>value <b>test</b></p>

Nest properly.

HTML

.Product {{ color: #fff; }}

Correct.

CSS

println('value')

println("value")

Double quotes.

Scala

List(20,30,15)

Correct.

Scala

let mut x=91; let r1=&mut x; let ref2=&mut x;

let mut x=91; {{ let r1=&mut x; }} let ref2=&mut x;

Only one mutable borrow.

Rust

if [ $bar = 22 ]; then

if [ "$bar" = 22 ]; then

Quote variable.

Shell

package main func main() {{}}

package main import 'fmt' func main() {{}}

Import needed.

Go

print 'message'

print 'message';

Add semicolon.

Perl

for (int i=0; i<88; i++) {{}}

Correct.

Java

let val = 'test'

let val = "test"

Double quotes.

Swift

int[] list = new int[54]; list[54] = 5;

int[] list = new int[54]; if (54 < list.length) list[54] = 5;

Check bounds.

Java

print 'info'

print('info')

print needs parentheses.

Python

const user:Person = {{name:'test'}};

const user:Person = {{name:'test', age:58}};

Add missing property.

TypeScript

os.sqrt(26)

import os os.sqrt(26)

Import module first.

Python

<?php // code ?>

Correct.

PHP

x <- 5; if (x > 3) print('large')

Correct.

R

name: hello age: 30

Correct.

YAML