rust/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.rs
Matthew Jasper 333388fd3c Move let expression checking to parsing
There was an incomplete version of the check in parsing and a second
version in AST validation. This meant that some, but not all, invalid
uses were allowed inside macros/disabled cfgs. It also means that later
passes have a hard time knowing when the let expression is in a valid
location, sometimes causing ICEs.

- Add a field to ExprKind::Let in AST/HIR to mark whether it's in a
  valid location.
- Suppress later errors and MIR construction for invalid let
  expressions.
2023-09-11 15:51:18 +00:00

48 lines
1.1 KiB
Rust

#![feature(let_chains)]
fn main() {
let _opt = Some(1i32);
#[cfg(FALSE)]
{
let _ = &&let Some(x) = Some(42);
//~^ ERROR expected expression, found `let` statement
}
#[cfg(FALSE)]
{
if let Some(elem) = _opt && [1, 2, 3][let _ = &&let Some(x) = Some(42)] = 1 {
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
true
}
}
#[cfg(FALSE)]
{
if let Some(elem) = _opt && {
[1, 2, 3][let _ = ()];
//~^ ERROR expected expression, found `let` statement
true
} {
}
}
#[cfg(FALSE)]
{
if let Some(elem) = _opt && [1, 2, 3][let _ = ()] = 1 {
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
true
}
}
#[cfg(FALSE)]
{
if let a = 1 && {
let x = let y = 1;
//~^ ERROR expected expression, found `let` statement
} {
}
}
}