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Diffstat (limited to 'src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs')
-rw-r--r--src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs480
1 files changed, 480 insertions, 0 deletions
diff --git a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs
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index 000000000..2a9a5472b
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+++ b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.rs
@@ -0,0 +1,480 @@
+// 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 `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ if (((let 0 = 1))) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ if (let 0 = 1) && true {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ if true && (let 0 = 1) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ if (let 0 = 1) && (let 0 = 1) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ while (((let 0 = 1))) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ while (let 0 = 1) && true {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ while true && (let 0 = 1) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ while (let 0 = 1) && (let 0 = 1) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ use_expr!((let 0 = 1));
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+}
+
+fn nested_within_if_expr() {
+ if &let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+
+ if !let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ if *let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR type `bool` cannot be dereferenced
+ //~| ERROR expected expression, found `let` statement
+ if -let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR cannot apply unary operator `-` to type `bool`
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR the `?` operator can only be applied to values that implement `Try`
+ //~| ERROR the `?` operator can only be used in a function that returns `Result`
+ //~| ERROR expected expression, found `let` statement
+
+ if true || let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ if (true || let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ if true && (true || let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ if true || (true && let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ let mut x = true;
+ if x = let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+
+ if true..(let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+ if ..(let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+ if (let 0 = 0).. {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+
+ // Binds as `(let ... = true)..true &&/|| false`.
+ if let Range { start: _, end: _ } = true..true && false {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+ if let Range { start: _, end: _ } = true..true || false {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+
+ // Binds as `(let Range { start: true, end } = t)..(&&false)`.
+ let t = &&true;
+ if let Range { start: true, end } = t..&&false {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+
+ if let true = let true = true {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+}
+
+fn nested_within_while_expr() {
+ while &let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+
+ while !let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ while *let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR type `bool` cannot be dereferenced
+ //~| ERROR expected expression, found `let` statement
+ while -let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR cannot apply unary operator `-` to type `bool`
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR the `?` operator can only be applied to values that implement `Try`
+ //~| ERROR the `?` operator can only be used in a function that returns `Result`
+ //~| ERROR expected expression, found `let` statement
+
+ while true || let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ while (true || let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ while true && (true || let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ while true || (true && let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ let mut x = true;
+ while x = let 0 = 0 {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+
+ while true..(let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+ while ..(let 0 = 0) {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+ while (let 0 = 0).. {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+
+ // Binds as `(let ... = true)..true &&/|| false`.
+ while let Range { start: _, end: _ } = true..true && false {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+ while let Range { start: _, end: _ } = true..true || false {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+
+ // Binds as `(let Range { start: true, end } = t)..(&&false)`.
+ let t = &&true;
+ while let Range { start: true, end } = t..&&false {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+
+ while let true = let true = true {}
+ //~^ ERROR `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ !let 0 = 0;
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ *let 0 = 0;
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR type `bool` cannot be dereferenced
+ //~| ERROR expected expression, found `let` statement
+ -let 0 = 0;
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR cannot apply unary operator `-` to type `bool`
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR the `?` operator can only be used in a function that returns `Result`
+ //~| ERROR the `?` operator can only be applied to values that implement `Try`
+ //~| ERROR expected expression, found `let` statement
+
+ true || let 0 = 0;
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ (true || let 0 = 0);
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ true && (true || let 0 = 0);
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ let mut x = true;
+ x = let 0 = 0;
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ true..(let 0 = 0);
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ ..(let 0 = 0);
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ (let 0 = 0)..;
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+
+ (let Range { start: _, end: _ } = true..true || false);
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR expected expression, found `let` statement
+
+ (let true = let true = true);
+ //~^ ERROR `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ }>::O = 5 {}
+
+ while let A::<{
+ true && let 1 = 1
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ }>::O = 5 {}
+
+ if A::<{
+ true && let 1 = 1
+ //~^ ERROR `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ }
+
+ if (let Some(a) = opt) && true {
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ }
+ if (let Some(a) = opt) && (let Some(b) = a) {
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| 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 `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ //~| ERROR expected expression, found `let` statement
+ }
+ if (let Some(a) = opt && (let Some(b) = a)) && true {
+ //~^ ERROR `let` expressions are not supported here
+ //~| ERROR `let` expressions are not supported here
+ //~| ERROR expected expression, found `let` statement
+ //~| ERROR expected expression, found `let` statement
+ }
+ if (let Some(a) = opt && (true)) && true {
+ //~^ ERROR `let` expressions are not supported here
+ //~| 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
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-09 12:31:06 +0000