Correcting grammer for nicer errors

[Quan1umMango]

I'm experimenting with Pest and wanted to make a let statement parser. I was stuck on meaningful error reporting.
Heres the grammer:

WHITESPACE = _{" "|"\r\n" | "\n"}
semi = _{";"}
let_keyword = _{"let"}
ident = {ASCII_ALPHA ~ (ASCII_DIGIT | ASCII_ALPHA|"_")*}
assign = _{"="}


add = {"+"}
sub = {"-"}
mul = {"*"}
div = {"/"}

bin_op = _{ add | sub | mul | div }
int_lit =  {ASCII_DIGIT+}

expr = { string_lit | int_expr }

string_lit= { "\"" ~ (!("\"" | "\n" | "\r") ~ ANY)* ~ "\"" }

int_expr = {int_lit ~ (bin_op ~ int_expr)*}
let_stmt = { let_keyword ~ ident ~ assign ~ expr ~ semi}
program = _{SOI ~ let_stmt+ ~ EOI}

The current output:

 --> 1:1
  |
1 | let x = "10+2" + 2;
  | ^---
  |
  = expected let_stmt

The desired output:

 --> 1:1
  |
1 | let x = "10+2" + 2;
  |                ^---
  |
  = unexpected bin_op

How should i transform the grammer to get this?

[Quan1umMango]

I got this solution, but if theres a better way, please let me know:

WHITESPACE = _{" "|"\r\n" | "\n"}
semi = _{";"}
let_keyword = _{"let"}
ident = {ASCII_ALPHA ~ (ASCII_DIGIT | ASCII_ALPHA|"_")*}
assign = _{"="}


add = {"+"}
sub = {"-"}
mul = {"*"}
div = {"/"}

bin_op = _{ add | sub | mul | div }
int_lit =  {ASCII_DIGIT+}

expr = { ((string_lit) ~ (add~string_lit)* ~ semi )| (int_expr ~semi)  }

string_lit= { "\"" ~ (!("\"" | "\n" | "\r") ~ ANY)* ~ "\"" }

int_expr = {int_lit ~ (bin_op ~ int_expr)*}
let_stmt = { let_keyword ~ ident ~ assign ~ expr}
program = _{SOI ~ let_stmt+ ~ EOI}