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|
// Here we test that `lowering` behaves correctly wrt. `let $pats = $expr` expressions.
//
// We want to make sure that `let` is banned in situations other than:
//
// expr =
// | ...
// | "if" expr_with_let block {"else" block}?
// | {label ":"}? while" expr_with_let block
// ;
//
// expr_with_let =
// | "let" top_pats "=" expr
// | expr_with_let "&&" expr_with_let
// | "(" expr_with_let ")"
// | expr
// ;
//
// To that end, we check some positions which is not part of the language above.
#![feature(let_chains)] // Avoid inflating `.stderr` with overzealous gates in this test.
#![allow(irrefutable_let_patterns)]
use std::ops::Range;
fn main() {}
fn _if() {
if (let 0 = 1) {}
//~^ ERROR expected expression, found `let` statement
if (((let 0 = 1))) {}
//~^ ERROR expected expression, found `let` statement
if (let 0 = 1) && true {}
//~^ ERROR expected expression, found `let` statement
if true && (let 0 = 1) {}
//~^ ERROR expected expression, found `let` statement
if (let 0 = 1) && (let 0 = 1) {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
}
fn _while() {
while (let 0 = 1) {}
//~^ ERROR expected expression, found `let` statement
while (((let 0 = 1))) {}
//~^ ERROR expected expression, found `let` statement
while (let 0 = 1) && true {}
//~^ ERROR expected expression, found `let` statement
while true && (let 0 = 1) {}
//~^ ERROR expected expression, found `let` statement
while (let 0 = 1) && (let 0 = 1) {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
}
fn _macros() {
macro_rules! use_expr {
($e:expr) => {
if $e {}
while $e {}
}
}
use_expr!((let 0 = 1 && 0 == 0));
//~^ ERROR expected expression, found `let` statement
use_expr!((let 0 = 1));
//~^ ERROR expected expression, found `let` statement
}
fn nested_within_if_expr() {
if &let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
if !let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
if *let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
if -let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
fn _check_try_binds_tighter() -> Result<(), ()> {
if let 0 = 0? {}
//~^ ERROR the `?` operator can only be applied to values that implement `Try`
Ok(())
}
if (let 0 = 0)? {}
//~^ ERROR expected expression, found `let` statement
if true || let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
if (true || let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
if true && (true || let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
if true || (true && let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
let mut x = true;
if x = let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
if true..(let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
if ..(let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
if (let 0 = 0).. {}
//~^ ERROR expected expression, found `let` statement
// Binds as `(let ... = true)..true &&/|| false`.
if let Range { start: _, end: _ } = true..true && false {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
if let Range { start: _, end: _ } = true..true || false {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
// Binds as `(let Range { start: F, end } = F)..(|| true)`.
const F: fn() -> bool = || true;
if let Range { start: F, end } = F..|| true {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
// Binds as `(let Range { start: true, end } = t)..(&&false)`.
let t = &&true;
if let Range { start: true, end } = t..&&false {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
if let true = let true = true {}
//~^ ERROR expected expression, found `let` statement
}
fn nested_within_while_expr() {
while &let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
while !let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
while *let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
while -let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
fn _check_try_binds_tighter() -> Result<(), ()> {
while let 0 = 0? {}
//~^ ERROR the `?` operator can only be applied to values that implement `Try`
Ok(())
}
while (let 0 = 0)? {}
//~^ ERROR expected expression, found `let` statement
while true || let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
while (true || let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
while true && (true || let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
while true || (true && let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
let mut x = true;
while x = let 0 = 0 {}
//~^ ERROR expected expression, found `let` statement
while true..(let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
while ..(let 0 = 0) {}
//~^ ERROR expected expression, found `let` statement
while (let 0 = 0).. {}
//~^ ERROR expected expression, found `let` statement
// Binds as `(let ... = true)..true &&/|| false`.
while let Range { start: _, end: _ } = true..true && false {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
while let Range { start: _, end: _ } = true..true || false {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
// Binds as `(let Range { start: F, end } = F)..(|| true)`.
const F: fn() -> bool = || true;
while let Range { start: F, end } = F..|| true {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
// Binds as `(let Range { start: true, end } = t)..(&&false)`.
let t = &&true;
while let Range { start: true, end } = t..&&false {}
//~^ ERROR expected expression, found `let` statement
//~| ERROR mismatched types
while let true = let true = true {}
//~^ ERROR expected expression, found `let` statement
}
fn not_error_because_clarified_intent() {
if let Range { start: _, end: _ } = (true..true || false) { }
if let Range { start: _, end: _ } = (true..true && false) { }
while let Range { start: _, end: _ } = (true..true || false) { }
while let Range { start: _, end: _ } = (true..true && false) { }
}
fn outside_if_and_while_expr() {
&let 0 = 0;
//~^ ERROR expected expression, found `let` statement
!let 0 = 0;
//~^ ERROR expected expression, found `let` statement
*let 0 = 0;
//~^ ERROR expected expression, found `let` statement
-let 0 = 0;
//~^ ERROR expected expression, found `let` statement
fn _check_try_binds_tighter() -> Result<(), ()> {
let 0 = 0?;
//~^ ERROR the `?` operator can only be applied to values that implement `Try`
Ok(())
}
(let 0 = 0)?;
//~^ ERROR expected expression, found `let` statement
true || let 0 = 0;
//~^ ERROR expected expression, found `let` statement
(true || let 0 = 0);
//~^ ERROR expected expression, found `let` statement
true && (true || let 0 = 0);
//~^ ERROR expected expression, found `let` statement
let mut x = true;
x = let 0 = 0;
//~^ ERROR expected expression, found `let` statement
true..(let 0 = 0);
//~^ ERROR expected expression, found `let` statement
..(let 0 = 0);
//~^ ERROR expected expression, found `let` statement
(let 0 = 0)..;
//~^ ERROR expected expression, found `let` statement
(let Range { start: _, end: _ } = true..true || false);
//~^ ERROR mismatched types
//~| ERROR expected expression, found `let` statement
(let true = let true = true);
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
{
#[cfg(FALSE)]
let x = true && let y = 1;
//~^ ERROR expected expression, found `let` statement
}
#[cfg(FALSE)]
{
[1, 2, 3][let _ = ()]
//~^ ERROR expected expression, found `let` statement
}
// Check function tail position.
&let 0 = 0
//~^ ERROR expected expression, found `let` statement
}
// Let's make sure that `let` inside const generic arguments are considered.
fn inside_const_generic_arguments() {
struct A<const B: bool>;
impl<const B: bool> A<{B}> { const O: u32 = 5; }
if let A::<{
true && let 1 = 1
//~^ ERROR expected expression, found `let` statement
}>::O = 5 {}
while let A::<{
true && let 1 = 1
//~^ ERROR expected expression, found `let` statement
}>::O = 5 {}
if A::<{
true && let 1 = 1
//~^ ERROR expected expression, found `let` statement
}>::O == 5 {}
// In the cases above we have `ExprKind::Block` to help us out.
// Below however, we would not have a block and so an implementation might go
// from visiting expressions to types without banning `let` expressions down the tree.
// This tests ensures that we are not caught by surprise should the parser
// admit non-IDENT expressions in const generic arguments.
if A::<
true && let 1 = 1
//~^ ERROR expressions must be enclosed in braces
//~| ERROR expected expression, found `let` statement
>::O == 5 {}
}
fn with_parenthesis() {
let opt = Some(Some(1i32));
if (let Some(a) = opt && true) {
//~^ ERROR expected expression, found `let` statement
}
if (let Some(a) = opt) && true {
//~^ ERROR expected expression, found `let` statement
}
if (let Some(a) = opt) && (let Some(b) = a) {
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
}
if let Some(a) = opt && (true && true) {
}
if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
}
if (let Some(a) = opt && (let Some(b) = a)) && true {
//~^ ERROR expected expression, found `let` statement
//~| ERROR expected expression, found `let` statement
}
if (let Some(a) = opt && (true)) && true {
//~^ ERROR expected expression, found `let` statement
}
if (true && (true)) && let Some(a) = opt {
}
if (true) && let Some(a) = opt {
}
if true && let Some(a) = opt {
}
let fun = || true;
if let true = (true && fun()) && (true) {
}
#[cfg(FALSE)]
let x = (true && let y = 1);
//~^ ERROR expected expression, found `let` statement
#[cfg(FALSE)]
{
([1, 2, 3][let _ = ()])
//~^ ERROR expected expression, found `let` statement
}
}
|
