Merging upstream version 1.72.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

27 files changed, 3366 insertions, 0 deletions

diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs
new file mode 100644
index 000000000..d851fac8e
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs
@@ -0,0 +1,16 @@
+// run-pass
+
+#![feature(let_chains)]
+#![allow(irrefutable_let_patterns)]
+
+fn main() {
+    let first = Some(1);
+    let second = Some(2);
+    let mut n = 0;
+    if let x = first && let y = second && 1 == 1 {
+        assert_eq!(x, first);
+        assert_eq!(y, second);
+        n = 1;
+    }
+    assert_eq!(n, 1);
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-pretty-check.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-pretty-check.rs
new file mode 100644
index 000000000..69bc189dd
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-pretty-check.rs
@@ -0,0 +1,6 @@
+// check-pass
+// compile-flags: -Z unpretty=expanded
+
+fn main() {
+    if let 0 = 1 {}
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-pretty-check.stdout b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-pretty-check.stdout
new file mode 100644
index 000000000..e737ef26e
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-pretty-check.stdout
@@ -0,0 +1,10 @@
+#![feature(prelude_import)]
+#![no_std]
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+#[macro_use]
+extern crate std;
+// check-pass
+// compile-flags: -Z unpretty=expanded
+
+fn main() { if let 0 = 1 {} }
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-validate-guards.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-validate-guards.rs
new file mode 100644
index 000000000..e6dee2a1d
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-validate-guards.rs
@@ -0,0 +1,23 @@
+#![feature(let_chains)]
+
+fn let_or_guard(x: Result<Option<i32>, ()>) {
+    match x {
+        Ok(opt) if let Some(4) = opt || false  => {}
+        //~^ ERROR `let` expressions are not supported here
+        _ => {}
+    }
+}
+
+fn hiding_unsafe_mod(x: Result<Option<i32>, ()>) {
+    match x {
+        Ok(opt)
+            if {
+                unsafe mod a {};
+                //~^ ERROR module cannot be declared unsafe
+                false
+            } => {}
+        _ => {}
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-validate-guards.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-validate-guards.stderr
new file mode 100644
index 000000000..26850998c
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/ast-validate-guards.stderr
@@ -0,0 +1,21 @@
+error: `let` expressions are not supported here
+  --> $DIR/ast-validate-guards.rs:5:20
+   |
+LL |         Ok(opt) if let Some(4) = opt || false  => {}
+   |                    ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/ast-validate-guards.rs:5:38
+   |
+LL |         Ok(opt) if let Some(4) = opt || false  => {}
+   |                                      ^^
+
+error: module cannot be declared unsafe
+  --> $DIR/ast-validate-guards.rs:15:17
+   |
+LL |                 unsafe mod a {};
+   |                 ^^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/chains-without-let.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/chains-without-let.rs
new file mode 100644
index 000000000..e0dded152
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/chains-without-let.rs
@@ -0,0 +1,20 @@
+fn and_chain() {
+    let z;
+    if true && { z = 3; true} && z == 3 {}
+    //~^ ERROR E0381
+}
+
+fn and_chain_2() {
+    let z;
+    true && { z = 3; true} && z == 3;
+    //~^ ERROR E0381
+}
+
+fn or_chain() {
+    let z;
+    if false || { z = 3; false} || z == 3 {}
+    //~^ ERROR E0381
+}
+
+fn main() {
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/chains-without-let.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/chains-without-let.stderr
new file mode 100644
index 000000000..30d5a6779
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/chains-without-let.stderr
@@ -0,0 +1,33 @@
+error[E0381]: used binding `z` is possibly-uninitialized
+  --> $DIR/chains-without-let.rs:3:34
+   |
+LL |     let z;
+   |         - binding declared here but left uninitialized
+LL |     if true && { z = 3; true} && z == 3 {}
+   |                  -----           ^ `z` used here but it is possibly-uninitialized
+   |                  |
+   |                  binding initialized here in some conditions
+
+error[E0381]: used binding `z` is possibly-uninitialized
+  --> $DIR/chains-without-let.rs:9:31
+   |
+LL |     let z;
+   |         - binding declared here but left uninitialized
+LL |     true && { z = 3; true} && z == 3;
+   |               -----           ^ `z` used here but it is possibly-uninitialized
+   |               |
+   |               binding initialized here in some conditions
+
+error[E0381]: used binding `z` is possibly-uninitialized
+  --> $DIR/chains-without-let.rs:15:36
+   |
+LL |     let z;
+   |         - binding declared here but left uninitialized
+LL |     if false || { z = 3; false} || z == 3 {}
+   |                   -----            ^ `z` used here but it is possibly-uninitialized
+   |                   |
+   |                   binding initialized here in some conditions
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0381`.
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.rs
new file mode 100644
index 000000000..2a9a5472b
--- /dev/null
+++ b/tests/ui/rfcs/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
+    }
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.stderr
new file mode 100644
index 000000000..81933173c
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.stderr
@@ -0,0 +1,1911 @@
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:29:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:33:11
+   |
+LL |     if (((let 0 = 1))) {}
+   |           ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:37:9
+   |
+LL |     if (let 0 = 1) && true {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:41:17
+   |
+LL |     if true && (let 0 = 1) {}
+   |                 ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:45:9
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:45:24
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |                        ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:51:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:51:48
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:51:61
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                             ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:61:12
+   |
+LL |     while (let 0 = 1) {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:65:14
+   |
+LL |     while (((let 0 = 1))) {}
+   |              ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:69:12
+   |
+LL |     while (let 0 = 1) && true {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:73:20
+   |
+LL |     while true && (let 0 = 1) {}
+   |                    ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:77:12
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:77:27
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |                           ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:83:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:83:51
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                   ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:83:64
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:110:9
+   |
+LL |     if &let 0 = 0 {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:115:9
+   |
+LL |     if !let 0 = 0 {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:118:9
+   |
+LL |     if *let 0 = 0 {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:122:9
+   |
+LL |     if -let 0 = 0 {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:132:9
+   |
+LL |     if (let 0 = 0)? {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:138:16
+   |
+LL |     if true || let 0 = 0 {}
+   |                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:141:17
+   |
+LL |     if (true || let 0 = 0) {}
+   |                 ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:144:25
+   |
+LL |     if true && (true || let 0 = 0) {}
+   |                         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:147:25
+   |
+LL |     if true || (true && let 0 = 0) {}
+   |                         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:152:12
+   |
+LL |     if x = let 0 = 0 {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:157:15
+   |
+LL |     if true..(let 0 = 0) {}
+   |               ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:161:11
+   |
+LL |     if ..(let 0 = 0) {}
+   |           ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:165:9
+   |
+LL |     if (let 0 = 0).. {}
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:196:19
+   |
+LL |     if let true = let true = true {}
+   |                   ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:202:12
+   |
+LL |     while &let 0 = 0 {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:207:12
+   |
+LL |     while !let 0 = 0 {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:210:12
+   |
+LL |     while *let 0 = 0 {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:214:12
+   |
+LL |     while -let 0 = 0 {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:224:12
+   |
+LL |     while (let 0 = 0)? {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:230:19
+   |
+LL |     while true || let 0 = 0 {}
+   |                   ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:233:20
+   |
+LL |     while (true || let 0 = 0) {}
+   |                    ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:236:28
+   |
+LL |     while true && (true || let 0 = 0) {}
+   |                            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:239:28
+   |
+LL |     while true || (true && let 0 = 0) {}
+   |                            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:244:15
+   |
+LL |     while x = let 0 = 0 {}
+   |               ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:249:18
+   |
+LL |     while true..(let 0 = 0) {}
+   |                  ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:253:14
+   |
+LL |     while ..(let 0 = 0) {}
+   |              ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:257:12
+   |
+LL |     while (let 0 = 0).. {}
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:288:22
+   |
+LL |     while let true = let true = true {}
+   |                      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:304:6
+   |
+LL |     &let 0 = 0;
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:308:6
+   |
+LL |     !let 0 = 0;
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:311:6
+   |
+LL |     *let 0 = 0;
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:315:6
+   |
+LL |     -let 0 = 0;
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:325:6
+   |
+LL |     (let 0 = 0)?;
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:331:13
+   |
+LL |     true || let 0 = 0;
+   |             ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:334:14
+   |
+LL |     (true || let 0 = 0);
+   |              ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:337:22
+   |
+LL |     true && (true || let 0 = 0);
+   |                      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:342:9
+   |
+LL |     x = let 0 = 0;
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:346:12
+   |
+LL |     true..(let 0 = 0);
+   |            ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:349:8
+   |
+LL |     ..(let 0 = 0);
+   |        ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:352:6
+   |
+LL |     (let 0 = 0)..;
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:356:6
+   |
+LL |     (let Range { start: _, end: _ } = true..true || false);
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:361:6
+   |
+LL |     (let true = let true = true);
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:361:17
+   |
+LL |     (let true = let true = true);
+   |                 ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:368:25
+   |
+LL |         let x = true && let y = 1;
+   |                         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:374:19
+   |
+LL |         [1, 2, 3][let _ = ()]
+   |                   ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:379:6
+   |
+LL |     &let 0 = 0
+   |      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:391:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:397:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:403:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:415:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^
+
+error: expressions must be enclosed in braces to be used as const generic arguments
+  --> $DIR/disallowed-positions.rs:415:9
+   |
+LL |         true && let 1 = 1
+   |         ^^^^^^^^^^^^^^^^^
+   |
+help: enclose the `const` expression in braces
+   |
+LL |         { true && let 1 = 1 }
+   |         +                   +
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:425:9
+   |
+LL |     if (let Some(a) = opt && true) {
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:430:9
+   |
+LL |     if (let Some(a) = opt) && true {
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:434:9
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:434:32
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |                                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:443:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:443:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |                               ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:449:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:449:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |                               ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:455:9
+   |
+LL |     if (let Some(a) = opt && (true)) && true {
+   |         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:472:22
+   |
+LL |     let x = (true && let y = 1);
+   |                      ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:477:20
+   |
+LL |         ([1, 2, 3][let _ = ()])
+   |                    ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:99:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/disallowed-positions.rs:103:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:29:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:29:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:33:11
+   |
+LL |     if (((let 0 = 1))) {}
+   |           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:33:11
+   |
+LL |     if (((let 0 = 1))) {}
+   |           ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:37:9
+   |
+LL |     if (let 0 = 1) && true {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:37:9
+   |
+LL |     if (let 0 = 1) && true {}
+   |         ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:41:17
+   |
+LL |     if true && (let 0 = 1) {}
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:41:17
+   |
+LL |     if true && (let 0 = 1) {}
+   |                 ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:45:9
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:45:9
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |         ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:45:24
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |                        ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:45:24
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |                        ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:51:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:51:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:51:48
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:51:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:51:61
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                             ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:51:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:61:12
+   |
+LL |     while (let 0 = 1) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:61:12
+   |
+LL |     while (let 0 = 1) {}
+   |            ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:65:14
+   |
+LL |     while (((let 0 = 1))) {}
+   |              ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:65:14
+   |
+LL |     while (((let 0 = 1))) {}
+   |              ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:69:12
+   |
+LL |     while (let 0 = 1) && true {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:69:12
+   |
+LL |     while (let 0 = 1) && true {}
+   |            ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:73:20
+   |
+LL |     while true && (let 0 = 1) {}
+   |                    ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:73:20
+   |
+LL |     while true && (let 0 = 1) {}
+   |                    ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:77:12
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:77:12
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |            ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:77:27
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |                           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:77:27
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |                           ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:83:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:83:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:83:51
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:83:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:83:64
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:83:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:99:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:99:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:99:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:99:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:103:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:103:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:103:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:103:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:110:9
+   |
+LL |     if &let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:115:9
+   |
+LL |     if !let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:118:9
+   |
+LL |     if *let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:122:9
+   |
+LL |     if -let 0 = 0 {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:132:9
+   |
+LL |     if (let 0 = 0)? {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:132:9
+   |
+LL |     if (let 0 = 0)? {}
+   |         ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:138:16
+   |
+LL |     if true || let 0 = 0 {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:138:13
+   |
+LL |     if true || let 0 = 0 {}
+   |             ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:141:17
+   |
+LL |     if (true || let 0 = 0) {}
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:141:14
+   |
+LL |     if (true || let 0 = 0) {}
+   |              ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:144:25
+   |
+LL |     if true && (true || let 0 = 0) {}
+   |                         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:144:22
+   |
+LL |     if true && (true || let 0 = 0) {}
+   |                      ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:147:25
+   |
+LL |     if true || (true && let 0 = 0) {}
+   |                         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:147:17
+   |
+LL |     if true || (true && let 0 = 0) {}
+   |                 ^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:152:12
+   |
+LL |     if x = let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:157:15
+   |
+LL |     if true..(let 0 = 0) {}
+   |               ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:157:15
+   |
+LL |     if true..(let 0 = 0) {}
+   |               ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:161:11
+   |
+LL |     if ..(let 0 = 0) {}
+   |           ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:161:11
+   |
+LL |     if ..(let 0 = 0) {}
+   |           ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:165:9
+   |
+LL |     if (let 0 = 0).. {}
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:165:9
+   |
+LL |     if (let 0 = 0).. {}
+   |         ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:171:8
+   |
+LL |     if let Range { start: _, end: _ } = true..true && false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:175:8
+   |
+LL |     if let Range { start: _, end: _ } = true..true || false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:182:8
+   |
+LL |     if let Range { start: F, end } = F..|| true {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:190:8
+   |
+LL |     if let Range { start: true, end } = t..&&false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:196:19
+   |
+LL |     if let true = let true = true {}
+   |                   ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:202:12
+   |
+LL |     while &let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:207:12
+   |
+LL |     while !let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:210:12
+   |
+LL |     while *let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:214:12
+   |
+LL |     while -let 0 = 0 {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:224:12
+   |
+LL |     while (let 0 = 0)? {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:224:12
+   |
+LL |     while (let 0 = 0)? {}
+   |            ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:230:19
+   |
+LL |     while true || let 0 = 0 {}
+   |                   ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:230:16
+   |
+LL |     while true || let 0 = 0 {}
+   |                ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:233:20
+   |
+LL |     while (true || let 0 = 0) {}
+   |                    ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:233:17
+   |
+LL |     while (true || let 0 = 0) {}
+   |                 ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:236:28
+   |
+LL |     while true && (true || let 0 = 0) {}
+   |                            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:236:25
+   |
+LL |     while true && (true || let 0 = 0) {}
+   |                         ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:239:28
+   |
+LL |     while true || (true && let 0 = 0) {}
+   |                            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:239:20
+   |
+LL |     while true || (true && let 0 = 0) {}
+   |                    ^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:244:15
+   |
+LL |     while x = let 0 = 0 {}
+   |               ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:249:18
+   |
+LL |     while true..(let 0 = 0) {}
+   |                  ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:249:18
+   |
+LL |     while true..(let 0 = 0) {}
+   |                  ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:253:14
+   |
+LL |     while ..(let 0 = 0) {}
+   |              ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:253:14
+   |
+LL |     while ..(let 0 = 0) {}
+   |              ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:257:12
+   |
+LL |     while (let 0 = 0).. {}
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:257:12
+   |
+LL |     while (let 0 = 0).. {}
+   |            ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:263:11
+   |
+LL |     while let Range { start: _, end: _ } = true..true && false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:267:11
+   |
+LL |     while let Range { start: _, end: _ } = true..true || false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:274:11
+   |
+LL |     while let Range { start: F, end } = F..|| true {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:282:11
+   |
+LL |     while let Range { start: true, end } = t..&&false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:288:22
+   |
+LL |     while let true = let true = true {}
+   |                      ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:304:6
+   |
+LL |     &let 0 = 0;
+   |      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:308:6
+   |
+LL |     !let 0 = 0;
+   |      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:311:6
+   |
+LL |     *let 0 = 0;
+   |      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:315:6
+   |
+LL |     -let 0 = 0;
+   |      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:325:6
+   |
+LL |     (let 0 = 0)?;
+   |      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:325:6
+   |
+LL |     (let 0 = 0)?;
+   |      ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:331:13
+   |
+LL |     true || let 0 = 0;
+   |             ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:331:10
+   |
+LL |     true || let 0 = 0;
+   |          ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:334:14
+   |
+LL |     (true || let 0 = 0);
+   |              ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:334:11
+   |
+LL |     (true || let 0 = 0);
+   |           ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:337:22
+   |
+LL |     true && (true || let 0 = 0);
+   |                      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/disallowed-positions.rs:337:19
+   |
+LL |     true && (true || let 0 = 0);
+   |                   ^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:342:9
+   |
+LL |     x = let 0 = 0;
+   |         ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:346:12
+   |
+LL |     true..(let 0 = 0);
+   |            ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:346:12
+   |
+LL |     true..(let 0 = 0);
+   |            ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:349:8
+   |
+LL |     ..(let 0 = 0);
+   |        ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:349:8
+   |
+LL |     ..(let 0 = 0);
+   |        ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:352:6
+   |
+LL |     (let 0 = 0)..;
+   |      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:352:6
+   |
+LL |     (let 0 = 0)..;
+   |      ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:356:6
+   |
+LL |     (let Range { start: _, end: _ } = true..true || false);
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:361:6
+   |
+LL |     (let true = let true = true);
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:361:6
+   |
+LL |     (let true = let true = true);
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:379:6
+   |
+LL |     &let 0 = 0
+   |      ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:391:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:397:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:403:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:415:17
+   |
+LL |         true && let 1 = 1
+   |                 ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:425:9
+   |
+LL |     if (let Some(a) = opt && true) {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:425:9
+   |
+LL |     if (let Some(a) = opt && true) {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:430:9
+   |
+LL |     if (let Some(a) = opt) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:430:9
+   |
+LL |     if (let Some(a) = opt) && true {
+   |         ^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:434:9
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:434:9
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |         ^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:434:32
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |                                ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:434:32
+   |
+LL |     if (let Some(a) = opt) && (let Some(b) = a) {
+   |                                ^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:443:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:443:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:443:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |                               ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:443:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && b == 1 {
+   |                               ^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:449:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:449:9
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:449:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |                               ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:449:31
+   |
+LL |     if (let Some(a) = opt && (let Some(b) = a)) && true {
+   |                               ^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/disallowed-positions.rs:455:9
+   |
+LL |     if (let Some(a) = opt && (true)) && true {
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/disallowed-positions.rs:455:9
+   |
+LL |     if (let Some(a) = opt && (true)) && true {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:110:8
+   |
+LL |     if &let 0 = 0 {}
+   |        ^^^^^^^^^^ expected `bool`, found `&bool`
+   |
+help: consider removing the borrow
+   |
+LL -     if &let 0 = 0 {}
+LL +     if let 0 = 0 {}
+   |
+
+error[E0614]: type `bool` cannot be dereferenced
+  --> $DIR/disallowed-positions.rs:118:8
+   |
+LL |     if *let 0 = 0 {}
+   |        ^^^^^^^^^^
+
+error[E0600]: cannot apply unary operator `-` to type `bool`
+  --> $DIR/disallowed-positions.rs:122:8
+   |
+LL |     if -let 0 = 0 {}
+   |        ^^^^^^^^^^ cannot apply unary operator `-`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:132:8
+   |
+LL |     if (let 0 = 0)? {}
+   |        ^^^^^^^^^^^^ the `?` operator cannot be applied to type `bool`
+   |
+   = help: the trait `Try` is not implemented for `bool`
+
+error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
+  --> $DIR/disallowed-positions.rs:132:19
+   |
+LL | fn nested_within_if_expr() {
+   | -------------------------- this function should return `Result` or `Option` to accept `?`
+...
+LL |     if (let 0 = 0)? {}
+   |                   ^ cannot use the `?` operator in a function that returns `()`
+   |
+   = help: the trait `FromResidual<_>` is not implemented for `()`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:152:8
+   |
+LL |     if x = let 0 = 0 {}
+   |        ^^^^^^^^^^^^^ expected `bool`, found `()`
+   |
+help: you might have meant to compare for equality
+   |
+LL |     if x == let 0 = 0 {}
+   |           +
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:157:8
+   |
+LL |     if true..(let 0 = 0) {}
+   |        ^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:161:8
+   |
+LL |     if ..(let 0 = 0) {}
+   |        ^^^^^^^^^^^^^ expected `bool`, found `RangeTo<bool>`
+   |
+   = note: expected type `bool`
+            found struct `RangeTo<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:165:8
+   |
+LL |     if (let 0 = 0).. {}
+   |        ^^^^^^^^^^^^^ expected `bool`, found `RangeFrom<bool>`
+   |
+   = note: expected type `bool`
+            found struct `RangeFrom<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:171:12
+   |
+LL |     if let Range { start: _, end: _ } = true..true && false {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |            |
+   |            expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:171:8
+   |
+LL |     if let Range { start: _, end: _ } = true..true && false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:175:12
+   |
+LL |     if let Range { start: _, end: _ } = true..true || false {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |            |
+   |            expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:175:8
+   |
+LL |     if let Range { start: _, end: _ } = true..true || false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:182:12
+   |
+LL |     if let Range { start: F, end } = F..|| true {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
+   |            |
+   |            expected fn pointer, found `Range<_>`
+   |
+   = note: expected fn pointer `fn() -> bool`
+                  found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:182:41
+   |
+LL |     if let Range { start: F, end } = F..|| true {}
+   |                                         ^^^^^^^ expected `bool`, found closure
+   |
+   = note: expected type `bool`
+           found closure `[closure@$DIR/disallowed-positions.rs:182:41: 182:43]`
+help: use parentheses to call this closure
+   |
+LL |     if let Range { start: F, end } = F..(|| true)() {}
+   |                                         +       +++
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:182:8
+   |
+LL |     if let Range { start: F, end } = F..|| true {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:190:12
+   |
+LL |     if let Range { start: true, end } = t..&&false {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
+   |            |
+   |            expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:190:44
+   |
+LL |     if let Range { start: true, end } = t..&&false {}
+   |                                            ^^^^^^^ expected `bool`, found `&&bool`
+   |
+help: consider removing the `&&`
+   |
+LL -     if let Range { start: true, end } = t..&&false {}
+LL +     if let Range { start: true, end } = t..false {}
+   |
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:190:8
+   |
+LL |     if let Range { start: true, end } = t..&&false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:128:20
+   |
+LL |         if let 0 = 0? {}
+   |                    ^^ the `?` operator cannot be applied to type `{integer}`
+   |
+   = help: the trait `Try` is not implemented for `{integer}`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:202:11
+   |
+LL |     while &let 0 = 0 {}
+   |           ^^^^^^^^^^ expected `bool`, found `&bool`
+   |
+help: consider removing the borrow
+   |
+LL -     while &let 0 = 0 {}
+LL +     while let 0 = 0 {}
+   |
+
+error[E0614]: type `bool` cannot be dereferenced
+  --> $DIR/disallowed-positions.rs:210:11
+   |
+LL |     while *let 0 = 0 {}
+   |           ^^^^^^^^^^
+
+error[E0600]: cannot apply unary operator `-` to type `bool`
+  --> $DIR/disallowed-positions.rs:214:11
+   |
+LL |     while -let 0 = 0 {}
+   |           ^^^^^^^^^^ cannot apply unary operator `-`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:224:11
+   |
+LL |     while (let 0 = 0)? {}
+   |           ^^^^^^^^^^^^ the `?` operator cannot be applied to type `bool`
+   |
+   = help: the trait `Try` is not implemented for `bool`
+
+error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
+  --> $DIR/disallowed-positions.rs:224:22
+   |
+LL | fn nested_within_while_expr() {
+   | ----------------------------- this function should return `Result` or `Option` to accept `?`
+...
+LL |     while (let 0 = 0)? {}
+   |                      ^ cannot use the `?` operator in a function that returns `()`
+   |
+   = help: the trait `FromResidual<_>` is not implemented for `()`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:244:11
+   |
+LL |     while x = let 0 = 0 {}
+   |           ^^^^^^^^^^^^^ expected `bool`, found `()`
+   |
+help: you might have meant to compare for equality
+   |
+LL |     while x == let 0 = 0 {}
+   |              +
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:249:11
+   |
+LL |     while true..(let 0 = 0) {}
+   |           ^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:253:11
+   |
+LL |     while ..(let 0 = 0) {}
+   |           ^^^^^^^^^^^^^ expected `bool`, found `RangeTo<bool>`
+   |
+   = note: expected type `bool`
+            found struct `RangeTo<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:257:11
+   |
+LL |     while (let 0 = 0).. {}
+   |           ^^^^^^^^^^^^^ expected `bool`, found `RangeFrom<bool>`
+   |
+   = note: expected type `bool`
+            found struct `RangeFrom<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:263:15
+   |
+LL |     while let Range { start: _, end: _ } = true..true && false {}
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |               |
+   |               expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:263:11
+   |
+LL |     while let Range { start: _, end: _ } = true..true && false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:267:15
+   |
+LL |     while let Range { start: _, end: _ } = true..true || false {}
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |               |
+   |               expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:267:11
+   |
+LL |     while let Range { start: _, end: _ } = true..true || false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:274:15
+   |
+LL |     while let Range { start: F, end } = F..|| true {}
+   |               ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `fn() -> bool`
+   |               |
+   |               expected fn pointer, found `Range<_>`
+   |
+   = note: expected fn pointer `fn() -> bool`
+                  found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:274:44
+   |
+LL |     while let Range { start: F, end } = F..|| true {}
+   |                                            ^^^^^^^ expected `bool`, found closure
+   |
+   = note: expected type `bool`
+           found closure `[closure@$DIR/disallowed-positions.rs:274:44: 274:46]`
+help: use parentheses to call this closure
+   |
+LL |     while let Range { start: F, end } = F..(|| true)() {}
+   |                                            +       +++
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:274:11
+   |
+LL |     while let Range { start: F, end } = F..|| true {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:282:15
+   |
+LL |     while let Range { start: true, end } = t..&&false {}
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `&&bool`
+   |               |
+   |               expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:282:47
+   |
+LL |     while let Range { start: true, end } = t..&&false {}
+   |                                               ^^^^^^^ expected `bool`, found `&&bool`
+   |
+help: consider removing the `&&`
+   |
+LL -     while let Range { start: true, end } = t..&&false {}
+LL +     while let Range { start: true, end } = t..false {}
+   |
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:282:11
+   |
+LL |     while let Range { start: true, end } = t..&&false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Range<bool>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<bool>`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:220:23
+   |
+LL |         while let 0 = 0? {}
+   |                       ^^ the `?` operator cannot be applied to type `{integer}`
+   |
+   = help: the trait `Try` is not implemented for `{integer}`
+
+error[E0614]: type `bool` cannot be dereferenced
+  --> $DIR/disallowed-positions.rs:311:5
+   |
+LL |     *let 0 = 0;
+   |     ^^^^^^^^^^
+
+error[E0600]: cannot apply unary operator `-` to type `bool`
+  --> $DIR/disallowed-positions.rs:315:5
+   |
+LL |     -let 0 = 0;
+   |     ^^^^^^^^^^ cannot apply unary operator `-`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:325:5
+   |
+LL |     (let 0 = 0)?;
+   |     ^^^^^^^^^^^^ the `?` operator cannot be applied to type `bool`
+   |
+   = help: the trait `Try` is not implemented for `bool`
+
+error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
+  --> $DIR/disallowed-positions.rs:325:16
+   |
+LL | fn outside_if_and_while_expr() {
+   | ------------------------------ this function should return `Result` or `Option` to accept `?`
+...
+LL |     (let 0 = 0)?;
+   |                ^ cannot use the `?` operator in a function that returns `()`
+   |
+   = help: the trait `FromResidual<_>` is not implemented for `()`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:356:10
+   |
+LL |     (let Range { start: _, end: _ } = true..true || false);
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^   ---- this expression has type `bool`
+   |          |
+   |          expected `bool`, found `Range<_>`
+   |
+   = note: expected type `bool`
+            found struct `std::ops::Range<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/disallowed-positions.rs:379:5
+   |
+LL | fn outside_if_and_while_expr() {
+   |                                - help: try adding a return type: `-> &bool`
+...
+LL |     &let 0 = 0
+   |     ^^^^^^^^^^ expected `()`, found `&bool`
+
+error[E0277]: the `?` operator can only be applied to values that implement `Try`
+  --> $DIR/disallowed-positions.rs:321:17
+   |
+LL |         let 0 = 0?;
+   |                 ^^ the `?` operator cannot be applied to type `{integer}`
+   |
+   = help: the trait `Try` is not implemented for `{integer}`
+
+error: aborting due to 215 previous errors
+
+Some errors have detailed explanations: E0277, E0308, E0600, E0614.
+For more information about an error, try `rustc --explain E0277`.
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
new file mode 100644
index 000000000..2a6c14435
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
@@ -0,0 +1,55 @@
+#![feature(let_chains)]
+
+fn main() {
+    let opt = Some(1i32);
+
+    let Some(n) = opt else {
+        return;
+    };
+    let Some(n) = opt && n == 1 else {
+    //~^ ERROR a `&&` expression cannot be directly assigned in `let...else`
+    //~| ERROR mismatched types
+    //~| ERROR mismatched types
+        return;
+    };
+    let Some(n) = opt && let another = n else {
+    //~^ ERROR a `&&` expression cannot be directly assigned in `let...else`
+    //~| ERROR `let` expressions are not supported here
+    //~| ERROR mismatched types
+    //~| ERROR mismatched types
+    //~| ERROR expected expression, found `let` statement
+        return;
+    };
+
+    if let Some(n) = opt else {
+    //~^ ERROR this `if` expression is missing a block after the condition
+        return;
+    };
+    if let Some(n) = opt && n == 1 else {
+    //~^ ERROR this `if` expression is missing a block after the condition
+        return;
+    };
+    if let Some(n) = opt && let another = n else {
+    //~^ ERROR this `if` expression is missing a block after the condition
+        return;
+    };
+
+    {
+        while let Some(n) = opt else {
+        //~^ ERROR expected `{`, found keyword `else`
+            return;
+        };
+    }
+    {
+        while let Some(n) = opt && n == 1 else {
+        //~^ ERROR expected `{`, found keyword `else`
+            return;
+        };
+    }
+    {
+        while let Some(n) = opt && let another = n else {
+        //~^ ERROR expected `{`, found keyword `else`
+            return;
+        };
+    }
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.stderr
new file mode 100644
index 000000000..9bc3e7541
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.stderr
@@ -0,0 +1,147 @@
+error: a `&&` expression cannot be directly assigned in `let...else`
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:9:19
+   |
+LL |     let Some(n) = opt && n == 1 else {
+   |                   ^^^^^^^^^^^^^
+   |
+help: wrap the expression in parentheses
+   |
+LL |     let Some(n) = (opt && n == 1) else {
+   |                   +             +
+
+error: expected expression, found `let` statement
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:26
+   |
+LL |     let Some(n) = opt && let another = n else {
+   |                          ^^^
+
+error: a `&&` expression cannot be directly assigned in `let...else`
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:19
+   |
+LL |     let Some(n) = opt && let another = n else {
+   |                   ^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: wrap the expression in parentheses
+   |
+LL |     let Some(n) = (opt && let another = n) else {
+   |                   +                      +
+
+error: this `if` expression is missing a block after the condition
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:24:5
+   |
+LL |     if let Some(n) = opt else {
+   |     ^^
+   |
+help: add a block here
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:24:25
+   |
+LL |     if let Some(n) = opt else {
+   |                         ^
+help: remove the `if` if you meant to write a `let...else` statement
+   |
+LL -     if let Some(n) = opt else {
+LL +     let Some(n) = opt else {
+   |
+
+error: this `if` expression is missing a block after the condition
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:28:5
+   |
+LL |     if let Some(n) = opt && n == 1 else {
+   |     ^^
+   |
+help: add a block here
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:28:35
+   |
+LL |     if let Some(n) = opt && n == 1 else {
+   |                                   ^
+
+error: this `if` expression is missing a block after the condition
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:32:5
+   |
+LL |     if let Some(n) = opt && let another = n else {
+   |     ^^
+   |
+help: add a block here
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:32:44
+   |
+LL |     if let Some(n) = opt && let another = n else {
+   |                                            ^
+
+error: expected `{`, found keyword `else`
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:38:33
+   |
+LL |         while let Some(n) = opt else {
+   |         ----- ----------------- ^^^^ expected `{`
+   |         |     |
+   |         |     this `while` condition successfully parsed
+   |         while parsing the body of this `while` expression
+
+error: expected `{`, found keyword `else`
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:44:43
+   |
+LL |         while let Some(n) = opt && n == 1 else {
+   |         ----- --------------------------- ^^^^ expected `{`
+   |         |     |
+   |         |     this `while` condition successfully parsed
+   |         while parsing the body of this `while` expression
+
+error: expected `{`, found keyword `else`
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:50:52
+   |
+LL |         while let Some(n) = opt && let another = n else {
+   |         ----- ------------------------------------ ^^^^ expected `{`
+   |         |     |
+   |         |     this `while` condition successfully parsed
+   |         while parsing the body of this `while` expression
+
+error: `let` expressions are not supported here
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:26
+   |
+LL |     let Some(n) = opt && let another = n else {
+   |                          ^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+
+error[E0308]: mismatched types
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:9:19
+   |
+LL |     let Some(n) = opt && n == 1 else {
+   |                   ^^^ expected `bool`, found `Option<i32>`
+   |
+   = note: expected type `bool`
+              found enum `Option<i32>`
+
+error[E0308]: mismatched types
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:9:9
+   |
+LL |     let Some(n) = opt && n == 1 else {
+   |         ^^^^^^^   ------------- this expression has type `bool`
+   |         |
+   |         expected `bool`, found `Option<_>`
+   |
+   = note: expected type `bool`
+              found enum `Option<_>`
+
+error[E0308]: mismatched types
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:19
+   |
+LL |     let Some(n) = opt && let another = n else {
+   |                   ^^^ expected `bool`, found `Option<i32>`
+   |
+   = note: expected type `bool`
+              found enum `Option<i32>`
+
+error[E0308]: mismatched types
+  --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:9
+   |
+LL |     let Some(n) = opt && let another = n else {
+   |         ^^^^^^^   ---------------------- this expression has type `bool`
+   |         |
+   |         expected `bool`, found `Option<_>`
+   |
+   = note: expected type `bool`
+              found enum `Option<_>`
+
+error: aborting due to 14 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/feature-gate.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/feature-gate.rs
new file mode 100644
index 000000000..2b407ef51
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/feature-gate.rs
@@ -0,0 +1,62 @@
+// gate-test-let_chains
+
+// Here we test feature gating for ´let_chains`.
+// See `disallowed-positions.rs` for the grammar
+// defining the language for gated allowed positions.
+
+#![allow(irrefutable_let_patterns)]
+
+use std::ops::Range;
+
+fn _if() {
+    if let 0 = 1 {} // Stable!
+
+    if true && let 0 = 1 {}
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+
+    if let 0 = 1 && true {}
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+
+    if let Range { start: _, end: _ } = (true..true) && false {}
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+
+    if let 1 = 1 && let true = { true } && false {
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR `let` expressions in this position are unstable [E0658]
+    }
+}
+
+fn _while() {
+    while let 0 = 1 {} // Stable!
+
+    while true && let 0 = 1 {}
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+
+    while let 0 = 1 && true {}
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+
+    while let Range { start: _, end: _ } = (true..true) && false {}
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+}
+
+fn _macros() {
+    macro_rules! noop_expr { ($e:expr) => {}; }
+
+    noop_expr!((let 0 = 1));
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR expected expression, found `let` statement
+
+    macro_rules! use_expr {
+        ($e:expr) => {
+            if $e {}
+            while $e {}
+        }
+    }
+    #[cfg(FALSE)] (let 0 = 1);
+    //~^ ERROR `let` expressions in this position are unstable [E0658]
+    //~| ERROR expected expression, found `let` statement
+    use_expr!(let 0 = 1);
+    //~^ ERROR no rules expected the token `let`
+}
+
+fn main() {}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/feature-gate.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/feature-gate.stderr
new file mode 100644
index 000000000..7a43b71fc
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/feature-gate.stderr
@@ -0,0 +1,120 @@
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:55:20
+   |
+LL |     #[cfg(FALSE)] (let 0 = 1);
+   |                    ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:45:17
+   |
+LL |     noop_expr!((let 0 = 1));
+   |                 ^^^
+
+error: no rules expected the token `let`
+  --> $DIR/feature-gate.rs:58:15
+   |
+LL |     macro_rules! use_expr {
+   |     --------------------- when calling this macro
+...
+LL |     use_expr!(let 0 = 1);
+   |               ^^^ no rules expected this token in macro call
+   |
+note: while trying to match meta-variable `$e:expr`
+  --> $DIR/feature-gate.rs:50:10
+   |
+LL |         ($e:expr) => {
+   |          ^^^^^^^
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:14:16
+   |
+LL |     if true && let 0 = 1 {}
+   |                ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:17:8
+   |
+LL |     if let 0 = 1 && true {}
+   |        ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:20:8
+   |
+LL |     if let Range { start: _, end: _ } = (true..true) && false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:23:8
+   |
+LL |     if let 1 = 1 && let true = { true } && false {
+   |        ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:23:21
+   |
+LL |     if let 1 = 1 && let true = { true } && false {
+   |                     ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:32:19
+   |
+LL |     while true && let 0 = 1 {}
+   |                   ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:35:11
+   |
+LL |     while let 0 = 1 && true {}
+   |           ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:38:11
+   |
+LL |     while let Range { start: _, end: _ } = (true..true) && false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:55:20
+   |
+LL |     #[cfg(FALSE)] (let 0 = 1);
+   |                    ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/feature-gate.rs:45:17
+   |
+LL |     noop_expr!((let 0 = 1));
+   |                 ^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error: aborting due to 13 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.rs
new file mode 100644
index 000000000..a942d1f4c
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.rs
@@ -0,0 +1,45 @@
+#![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
+            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
+            true
+        }
+    }
+    #[cfg(FALSE)]
+    {
+        if let a = 1 && {
+            let x = let y = 1;
+            //~^ ERROR expected expression, found `let` statement
+        } {
+        }
+    }
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.stderr
new file mode 100644
index 000000000..d1ce83c72
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.stderr
@@ -0,0 +1,38 @@
+error: expected expression, found `let` statement
+  --> $DIR/invalid-let-in-a-valid-let-context.rs:8:19
+   |
+LL |         let _ = &&let Some(x) = Some(42);
+   |                   ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/invalid-let-in-a-valid-let-context.rs:13:47
+   |
+LL |         if let Some(elem) = _opt && [1, 2, 3][let _ = &&let Some(x) = Some(42)] = 1 {
+   |                                               ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/invalid-let-in-a-valid-let-context.rs:13:57
+   |
+LL |         if let Some(elem) = _opt && [1, 2, 3][let _ = &&let Some(x) = Some(42)] = 1 {
+   |                                                         ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/invalid-let-in-a-valid-let-context.rs:23:23
+   |
+LL |             [1, 2, 3][let _ = ()];
+   |                       ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/invalid-let-in-a-valid-let-context.rs:32:47
+   |
+LL |         if let Some(elem) = _opt && [1, 2, 3][let _ = ()] = 1 {
+   |                                               ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/invalid-let-in-a-valid-let-context.rs:40:21
+   |
+LL |             let x = let y = 1;
+   |                     ^^^
+
+error: aborting due to 6 previous errors
+
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/irrefutable-lets.disallowed.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/irrefutable-lets.disallowed.stderr
new file mode 100644
index 000000000..be4a52315
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/irrefutable-lets.disallowed.stderr
@@ -0,0 +1,115 @@
+error: leading irrefutable pattern in let chain
+  --> $DIR/irrefutable-lets.rs:13:8
+   |
+LL |     if let first = &opt && let Some(ref second) = first && let None = second.start {}
+   |        ^^^^^^^^^^^^^^^^
+   |
+   = note: this pattern will always match
+   = help: consider moving it outside of the construct
+note: the lint level is defined here
+  --> $DIR/irrefutable-lets.rs:6:30
+   |
+LL | #![cfg_attr(disallowed, deny(irrefutable_let_patterns))]
+   |                              ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: irrefutable `if let` patterns
+  --> $DIR/irrefutable-lets.rs:19:8
+   |
+LL |     if let first = &opt && let (a, b) = (1, 2) {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: these patterns will always match, so the `if let` is useless
+   = help: consider replacing the `if let` with a `let`
+
+error: leading irrefutable pattern in let chain
+  --> $DIR/irrefutable-lets.rs:22:8
+   |
+LL |     if let first = &opt && let Some(ref second) = first && let None = second.start && let v = 0 {}
+   |        ^^^^^^^^^^^^^^^^
+   |
+   = note: this pattern will always match
+   = help: consider moving it outside of the construct
+
+error: trailing irrefutable pattern in let chain
+  --> $DIR/irrefutable-lets.rs:22:87
+   |
+LL |     if let first = &opt && let Some(ref second) = first && let None = second.start && let v = 0 {}
+   |                                                                                       ^^^^^^^^^
+   |
+   = note: this pattern will always match
+   = help: consider moving it into the body
+
+error: trailing irrefutable patterns in let chain
+  --> $DIR/irrefutable-lets.rs:26:37
+   |
+LL |     if let Some(ref first) = opt && let second = first && let _third = second {}
+   |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: these patterns will always match
+   = help: consider moving them into the body
+
+error: leading irrefutable pattern in let chain
+  --> $DIR/irrefutable-lets.rs:29:8
+   |
+LL |     if let Range { start: local_start, end: _ } = (None..Some(1)) && let None = local_start {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this pattern will always match
+   = help: consider moving it outside of the construct
+
+error: leading irrefutable pattern in let chain
+  --> $DIR/irrefutable-lets.rs:32:8
+   |
+LL |     if let (a, b, c) = (Some(1), Some(1), Some(1)) && let None = Some(1) {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this pattern will always match
+   = help: consider moving it outside of the construct
+
+error: leading irrefutable pattern in let chain
+  --> $DIR/irrefutable-lets.rs:35:8
+   |
+LL |     if let first = &opt && let None = Some(1) {}
+   |        ^^^^^^^^^^^^^^^^
+   |
+   = note: this pattern will always match
+   = help: consider moving it outside of the construct
+
+error: irrefutable `if let` guard patterns
+  --> $DIR/irrefutable-lets.rs:44:28
+   |
+LL |         Some(ref first) if let second = first && let _third = second && let v = 4 + 4 => {},
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: these patterns will always match, so the guard is useless
+   = help: consider removing the guard and adding a `let` inside the match arm
+
+error: trailing irrefutable patterns in let chain
+  --> $DIR/irrefutable-lets.rs:59:16
+   |
+LL |             && let v = local_end && let w = v => {},
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: these patterns will always match
+   = help: consider moving them into the body
+
+error: irrefutable `while let` patterns
+  --> $DIR/irrefutable-lets.rs:68:11
+   |
+LL |     while let first = &opt && let (a, b) = (1, 2) {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: these patterns will always match, so the loop will never exit
+   = help: consider instead using a `loop { ... }` with a `let` inside it
+
+error: trailing irrefutable patterns in let chain
+  --> $DIR/irrefutable-lets.rs:71:40
+   |
+LL |     while let Some(ref first) = opt && let second = first && let _third = second {}
+   |                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: these patterns will always match
+   = help: consider moving them into the body
+
+error: aborting due to 12 previous errors
+
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/irrefutable-lets.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/irrefutable-lets.rs
new file mode 100644
index 000000000..9afb6853b
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/irrefutable-lets.rs
@@ -0,0 +1,78 @@
+// revisions: allowed disallowed
+//[allowed] check-pass
+
+#![feature(if_let_guard, let_chains)]
+#![cfg_attr(allowed, allow(irrefutable_let_patterns))]
+#![cfg_attr(disallowed, deny(irrefutable_let_patterns))]
+
+use std::ops::Range;
+
+fn main() {
+    let opt = Some(None..Some(1));
+
+    if let first = &opt && let Some(ref second) = first && let None = second.start {}
+    //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+
+    // No lint as the irrefutable pattern is surrounded by other stuff
+    if 4 * 2 == 0 && let first = &opt && let Some(ref second) = first && let None = second.start {}
+
+    if let first = &opt && let (a, b) = (1, 2) {}
+    //[disallowed]~^ ERROR irrefutable `if let` patterns
+
+    if let first = &opt && let Some(ref second) = first && let None = second.start && let v = 0 {}
+    //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+    //[disallowed]~^^ ERROR trailing irrefutable pattern in let chain
+
+    if let Some(ref first) = opt && let second = first && let _third = second {}
+    //[disallowed]~^ ERROR trailing irrefutable patterns in let chain
+
+    if let Range { start: local_start, end: _ } = (None..Some(1)) && let None = local_start {}
+    //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+
+    if let (a, b, c) = (Some(1), Some(1), Some(1)) && let None = Some(1) {}
+    //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+
+    if let first = &opt && let None = Some(1) {}
+    //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+
+    if let Some(ref first) = opt
+        && let Range { start: local_start, end: _ } = first
+        && let None = local_start {
+    }
+
+    match opt {
+        Some(ref first) if let second = first && let _third = second && let v = 4 + 4 => {},
+        //[disallowed]~^ ERROR irrefutable `if let` guard patterns
+        _ => {}
+    }
+
+    // No error about leading irrefutable patterns: the expr on the rhs might
+    // use the bindings created by the match.
+    match opt {
+        Some(ref first) if let Range { start: local_start, end: _ } = first
+            && let None = local_start => {},
+        _ => {}
+    }
+
+    match opt {
+        Some(ref first) if let Range { start: Some(_), end: local_end } = first
+            && let v = local_end && let w = v => {},
+        //[disallowed]~^ ERROR trailing irrefutable patterns in let chain
+        _ => {}
+    }
+
+    // No error, despite the prefix being irrefutable: moving out could change the behaviour,
+    // due to possible side effects of the operation.
+    while let first = &opt && let Some(ref second) = first && let None = second.start {}
+
+    while let first = &opt && let (a, b) = (1, 2) {}
+    //[disallowed]~^ ERROR irrefutable `while let` patterns
+
+    while let Some(ref first) = opt && let second = first && let _third = second {}
+    //[disallowed]~^ ERROR trailing irrefutable patterns in let chain
+
+    while let Some(ref first) = opt
+        && let Range { start: local_start, end: _ } = first
+        && let None = local_start {
+    }
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-88498.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-88498.rs
new file mode 100644
index 000000000..3eb8a9ad0
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-88498.rs
@@ -0,0 +1,16 @@
+// check-pass
+
+pub enum UnOp {
+    Not(Vec<()>),
+}
+
+pub fn foo() {
+    if let Some(x) = None {
+        match x {
+            UnOp::Not(_) => {}
+        }
+    }
+}
+
+fn main() {
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-90722.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-90722.rs
new file mode 100644
index 000000000..6b7d88356
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-90722.rs
@@ -0,0 +1,11 @@
+// check-pass
+
+#![feature(let_chains)]
+
+fn main() {
+    let x = Some(vec!["test"]);
+
+    if let Some(v) = x && v.is_empty() {
+        println!("x == Some([])");
+    }
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-92145.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-92145.rs
new file mode 100644
index 000000000..7c7e31f4d
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-92145.rs
@@ -0,0 +1,11 @@
+// check-pass
+
+#![feature(let_chains)]
+
+fn main() {
+    let opt = Some("foo bar");
+
+    if true && let Some(x) = opt {
+        println!("{}", x);
+    }
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-93150.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-93150.rs
new file mode 100644
index 000000000..f90b9ab0d
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-93150.rs
@@ -0,0 +1,8 @@
+fn main() {
+    match true {
+        _ if let true = true && true => {}
+        //~^ ERROR `if let` guards are
+        //~| ERROR `let` expressions in this
+        _ => {}
+    }
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-93150.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-93150.stderr
new file mode 100644
index 000000000..b25f299a2
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-93150.stderr
@@ -0,0 +1,22 @@
+error[E0658]: `if let` guards are experimental
+  --> $DIR/issue-93150.rs:3:11
+   |
+LL |         _ if let true = true && true => {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #51114 <https://github.com/rust-lang/rust/issues/51114> for more information
+   = help: add `#![feature(if_let_guard)]` to the crate attributes to enable
+   = help: you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`
+
+error[E0658]: `let` expressions in this position are unstable
+  --> $DIR/issue-93150.rs:3:14
+   |
+LL |         _ if let true = true && true => {}
+   |              ^^^^^^^^^^^^^^^
+   |
+   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
+   = help: add `#![feature(let_chains)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-99938.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-99938.rs
new file mode 100644
index 000000000..bd81ce0b1
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/issue-99938.rs
@@ -0,0 +1,31 @@
+// compile-flags: -Zvalidate-mir -C opt-level=3
+// build-pass
+#![feature(let_chains)]
+struct TupleIter<T, I: Iterator<Item = T>> {
+    inner: I,
+}
+
+impl<T, I: Iterator<Item = T>> Iterator for TupleIter<T, I> {
+    type Item = (T, T, T);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let inner = &mut self.inner;
+
+        if let Some(first) = inner.next()
+            && let Some(second) = inner.next()
+            && let Some(third) = inner.next()
+        {
+            Some((first, second, third))
+        } else {
+            None
+        }
+    }
+}
+
+fn main() {
+    let vec: Vec<u8> = Vec::new();
+    let mut tup_iter = TupleIter {
+        inner: vec.into_iter(),
+    };
+    tup_iter.next();
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/no-double-assigments.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/no-double-assigments.rs
new file mode 100644
index 000000000..6b91c455e
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/no-double-assigments.rs
@@ -0,0 +1,9 @@
+// check-pass
+
+fn main() {
+    loop {
+        // [1][0] should leave top scope
+        if true && [1][0] == 1 && true {
+        }
+    }
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/protect-precedences.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/protect-precedences.rs
new file mode 100644
index 000000000..fcc09b159
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/protect-precedences.rs
@@ -0,0 +1,17 @@
+// run-pass
+
+#![allow(irrefutable_let_patterns)]
+
+fn main() {
+    let x: bool;
+    // This should associate as: `(x = (true && false));`.
+    x = true && false;
+    assert!(!x);
+
+    fn _f1() -> bool {
+        // Should associate as `(let _ = (return (true && false)))`.
+        if let _ = return true && false {};
+        //~^ WARNING unreachable block in `if`
+    }
+    assert!(!_f1());
+}
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/protect-precedences.stderr b/tests/ui/rfcs/rfc-2497-if-let-chains/protect-precedences.stderr
new file mode 100644
index 000000000..24b35a2ab
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/protect-precedences.stderr
@@ -0,0 +1,12 @@
+warning: unreachable block in `if` or `while` expression
+  --> $DIR/protect-precedences.rs:13:41
+   |
+LL |         if let _ = return true && false {};
+   |                    -------------------- ^^ unreachable block in `if` or `while` expression
+   |                    |
+   |                    any code following this expression is unreachable
+   |
+   = note: `#[warn(unreachable_code)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/then-else-blocks.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/then-else-blocks.rs
new file mode 100644
index 000000000..e061174f6
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2497-if-let-chains/then-else-blocks.rs
@@ -0,0 +1,49 @@
+// run-pass
+
+#![feature(if_let_guard, let_chains)]
+
+fn check_if_let(opt: Option<Option<Option<i32>>>, value: i32) -> bool {
+    if let Some(first) = opt
+        && let Some(second) = first
+        && let Some(third) = second
+        && third == value
+    {
+        true
+    }
+    else {
+        false
+    }
+}
+
+fn check_let_guard(opt: Option<Option<Option<i32>>>, value: i32) -> bool {
+    match opt {
+        Some(first) if let Some(second) = first && let Some(third) = second && third == value => {
+            true
+        }
+        _ => {
+            false
+        }
+    }
+}
+
+fn check_while_let(opt: Option<Option<Option<i32>>>, value: i32) -> bool {
+    while let Some(first) = opt
+        && let Some(second) = first
+        && let Some(third) = second
+        && third == value
+    {
+        return true;
+    }
+    false
+}
+
+fn main() {
+    assert_eq!(check_if_let(Some(Some(Some(1))), 1), true);
+    assert_eq!(check_if_let(Some(Some(Some(1))), 9), false);
+
+    assert_eq!(check_let_guard(Some(Some(Some(1))), 1), true);
+    assert_eq!(check_let_guard(Some(Some(Some(1))), 9), false);
+
+    assert_eq!(check_while_let(Some(Some(Some(1))), 1), true);
+    assert_eq!(check_while_let(Some(Some(Some(1))), 9), false);
+}