9 files changed, 512 insertions, 0 deletions
diff --git a/src/test/ui/rfc-2294-if-let-guard/bindings.rs b/src/test/ui/rfc-2294-if-let-guard/bindings.rs
new file mode 100644
index 000000000..1f32e4af1
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/bindings.rs
@@ -0,0 +1,9 @@
+#![feature(if_let_guard)]
+
+fn main() {
+    match Some(None) {
+        Some(x) if let Some(y) = x => (x, y),
+        _ => y, //~ ERROR cannot find value `y`
+    }
+    y //~ ERROR cannot find value `y`
+}
diff --git a/src/test/ui/rfc-2294-if-let-guard/bindings.stderr b/src/test/ui/rfc-2294-if-let-guard/bindings.stderr
new file mode 100644
index 000000000..2463b7f3e
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/bindings.stderr
@@ -0,0 +1,15 @@
+error[E0425]: cannot find value `y` in this scope
+  --> $DIR/bindings.rs:6:14
+   |
+LL |         _ => y,
+   |              ^ not found in this scope
+
+error[E0425]: cannot find value `y` in this scope
+  --> $DIR/bindings.rs:8:5
+   |
+LL |     y
+   |     ^ not found in this scope
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0425`.
diff --git a/src/test/ui/rfc-2294-if-let-guard/feature-gate.rs b/src/test/ui/rfc-2294-if-let-guard/feature-gate.rs
new file mode 100644
index 000000000..f0105e08e
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/feature-gate.rs
@@ -0,0 +1,84 @@
+// gate-test-if_let_guard
+
+use std::ops::Range;
+
+fn _if_let_guard() {
+    match () {
+        () if let 0 = 1 => {}
+        //~^ ERROR `if let` guards are experimental
+
+        () if (let 0 = 1) => {}
+        //~^ ERROR `let` expressions in this position are unstable
+        //~| ERROR expected expression, found `let` statement
+
+        () if (((let 0 = 1))) => {}
+        //~^ ERROR `let` expressions in this position are unstable
+        //~| ERROR expected expression, found `let` statement
+
+        () if true && let 0 = 1 => {}
+        //~^ ERROR `if let` guards are experimental
+        //~| ERROR `let` expressions in this position are unstable
+
+        () if let 0 = 1 && true => {}
+        //~^ ERROR `if let` guards are experimental
+        //~| ERROR `let` expressions in this position are unstable
+
+        () if (let 0 = 1) && true => {}
+        //~^ ERROR `let` expressions in this position are unstable
+        //~| ERROR expected expression, found `let` statement
+
+        () if true && (let 0 = 1) => {}
+        //~^ ERROR `let` expressions in this position are unstable
+        //~| ERROR expected expression, found `let` statement
+
+        () if (let 0 = 1) && (let 0 = 1) => {}
+        //~^ ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
+        //~| 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 `if let` guards are experimental
+        //~| ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
+        //~| ERROR `let` expressions in this position are unstable
+        //~| ERROR expected expression, found `let` statement
+        //~| ERROR expected expression, found `let` statement
+        //~| ERROR expected expression, found `let` statement
+
+        () if let Range { start: _, end: _ } = (true..true) && false => {}
+        //~^ ERROR `if let` guards are experimental
+        //~| ERROR `let` expressions in this position are unstable
+
+        _ => {}
+    }
+}
+
+fn _macros() {
+    macro_rules! use_expr {
+        ($e:expr) => {
+            match () {
+                () if $e => {}
+                _ => {}
+            }
+        }
+    }
+    use_expr!((let 0 = 1 && 0 == 0));
+    //~^ ERROR `let` expressions in this position are unstable
+    //~| ERROR expected expression, found `let` statement
+    use_expr!((let 0 = 1));
+    //~^ ERROR `let` expressions in this position are unstable
+    //~| ERROR expected expression, found `let` statement
+    match () {
+        #[cfg(FALSE)]
+        () if let 0 = 1 => {}
+        //~^ ERROR `if let` guards are experimental
+        _ => {}
+    }
+    use_expr!(let 0 = 1);
+    //~^ ERROR no rules expected the token `let`
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2294-if-let-guard/feature-gate.stderr b/src/test/ui/rfc-2294-if-let-guard/feature-gate.stderr
new file mode 100644
index 000000000..e017d04a5
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/feature-gate.stderr
@@ -0,0 +1,282 @@
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:10:16
+   |
+LL |         () if (let 0 = 1) => {}
+   |                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:14:18
+   |
+LL |         () if (((let 0 = 1))) => {}
+   |                  ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:26:16
+   |
+LL |         () if (let 0 = 1) && true => {}
+   |                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:30:24
+   |
+LL |         () if true && (let 0 = 1) => {}
+   |                        ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:34:16
+   |
+LL |         () if (let 0 = 1) && (let 0 = 1) => {}
+   |                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:34:31
+   |
+LL |         () if (let 0 = 1) && (let 0 = 1) => {}
+   |                               ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:40:42
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                          ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:40:55
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                                       ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:40:68
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                                                    ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:68:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^
+
+error: expected expression, found `let` statement
+  --> $DIR/feature-gate.rs:71:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^
+
+error: no rules expected the token `let`
+  --> $DIR/feature-gate.rs:80:15
+   |
+LL |     macro_rules! use_expr {
+   |     --------------------- when calling this macro
+...
+LL |     use_expr!(let 0 = 1);
+   |               ^^^ no rules expected this token in macro call
+
+error[E0658]: `if let` guards are experimental
+  --> $DIR/feature-gate.rs:7:12
+   |
+LL |         () if let 0 = 1 => {}
+   |            ^^^^^^^^^^^^
+   |
+   = 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]: `if let` guards are experimental
+  --> $DIR/feature-gate.rs:18:12
+   |
+LL |         () if true && let 0 = 1 => {}
+   |            ^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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]: `if let` guards are experimental
+  --> $DIR/feature-gate.rs:22:12
+   |
+LL |         () if let 0 = 1 && 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]: `if let` guards are experimental
+  --> $DIR/feature-gate.rs:40:12
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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]: `if let` guards are experimental
+  --> $DIR/feature-gate.rs:51:12
+   |
+LL |         () if let Range { start: _, end: _ } = (true..true) && false => {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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]: `if let` guards are experimental
+  --> $DIR/feature-gate.rs:76:12
+   |
+LL |         () if let 0 = 1 => {}
+   |            ^^^^^^^^^^^^
+   |
+   = 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/feature-gate.rs:10:16
+   |
+LL |         () if (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:14:18
+   |
+LL |         () if (((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:18:23
+   |
+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:22:15
+   |
+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:26:16
+   |
+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:30:24
+   |
+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:34:16
+   |
+LL |         () if (let 0 = 1) && (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:34:31
+   |
+LL |         () if (let 0 = 1) && (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:40:15
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |               ^^^^^^^^^
+   |
+   = 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:40:28
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                            ^^^^^^^^^
+   |
+   = 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:40:42
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                          ^^^^^^^^^
+   |
+   = 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:40:55
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                                       ^^^^^^^^^
+   |
+   = 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:40:68
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                                                    ^^^^^^^^^
+   |
+   = 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:51:15
+   |
+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:68:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^^^^^^^
+   |
+   = 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:71:16
+   |
+LL |     use_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 34 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/rfc-2294-if-let-guard/run-pass.rs b/src/test/ui/rfc-2294-if-let-guard/run-pass.rs
new file mode 100644
index 000000000..3da57989d
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/run-pass.rs
@@ -0,0 +1,33 @@
+// run-pass
+
+#![feature(if_let_guard)]
+
+enum Foo {
+    Bar,
+    Baz,
+    Qux(u8),
+}
+
+fn bar(x: bool) -> Foo {
+    if x { Foo::Baz } else { Foo::Bar }
+}
+
+fn baz(x: u8) -> Foo {
+    if x % 2 == 0 { Foo::Bar } else { Foo::Baz }
+}
+
+fn qux(x: u8) -> Foo {
+    Foo::Qux(x.rotate_left(1))
+}
+
+fn main() {
+    match Some((true, 3)) {
+        Some((x, _)) if let Foo::Bar = bar(x) => panic!(),
+        Some((_, x)) if let Foo::Baz = baz(x) => {},
+        _ => panic!(),
+    }
+    match Some(42) {
+        Some(x) if let Foo::Qux(y) = qux(x) => assert_eq!(y, 84),
+        _ => panic!(),
+    }
+}
diff --git a/src/test/ui/rfc-2294-if-let-guard/typeck.rs b/src/test/ui/rfc-2294-if-let-guard/typeck.rs
new file mode 100644
index 000000000..ad178dfa4
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/typeck.rs
@@ -0,0 +1,15 @@
+#![feature(if_let_guard)]
+
+fn ok() -> Result<Option<bool>, ()> {
+    Ok(Some(true))
+}
+
+fn main() {
+    match ok() {
+        Ok(x) if let Err(_) = x => {},
+        //~^ ERROR mismatched types
+        Ok(x) if let 0 = x => {},
+        //~^ ERROR mismatched types
+        _ => {}
+    }
+}
diff --git a/src/test/ui/rfc-2294-if-let-guard/typeck.stderr b/src/test/ui/rfc-2294-if-let-guard/typeck.stderr
new file mode 100644
index 000000000..dd1f4826f
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/typeck.stderr
@@ -0,0 +1,25 @@
+error[E0308]: mismatched types
+  --> $DIR/typeck.rs:9:22
+   |
+LL |         Ok(x) if let Err(_) = x => {},
+   |                      ^^^^^^   - this expression has type `Option<bool>`
+   |                      |
+   |                      expected enum `Option`, found enum `Result`
+   |
+   = note: expected enum `Option<bool>`
+              found enum `Result<_, _>`
+
+error[E0308]: mismatched types
+  --> $DIR/typeck.rs:11:22
+   |
+LL |         Ok(x) if let 0 = x => {},
+   |                      ^   - this expression has type `Option<bool>`
+   |                      |
+   |                      expected enum `Option`, found integer
+   |
+   = note: expected enum `Option<bool>`
+              found type `{integer}`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/rfc-2294-if-let-guard/warns.rs b/src/test/ui/rfc-2294-if-let-guard/warns.rs
new file mode 100644
index 000000000..3ad1a50c6
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/warns.rs
@@ -0,0 +1,21 @@
+#![feature(if_let_guard)]
+
+#[deny(irrefutable_let_patterns)]
+fn irrefutable_let_guard() {
+    match Some(()) {
+        Some(x) if let () = x => {}
+        //~^ ERROR irrefutable `if let` guard
+        _ => {}
+    }
+}
+
+#[deny(unreachable_patterns)]
+fn unreachable_pattern() {
+    match Some(()) {
+        x if let None | None = x => {}
+        //~^ ERROR unreachable pattern
+        _ => {}
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2294-if-let-guard/warns.stderr b/src/test/ui/rfc-2294-if-let-guard/warns.stderr
new file mode 100644
index 000000000..cf64513f9
--- /dev/null
+++ b/src/test/ui/rfc-2294-if-let-guard/warns.stderr
@@ -0,0 +1,28 @@
+error: irrefutable `if let` guard pattern
+  --> $DIR/warns.rs:6:24
+   |
+LL |         Some(x) if let () = x => {}
+   |                        ^^
+   |
+note: the lint level is defined here
+  --> $DIR/warns.rs:3:8
+   |
+LL | #[deny(irrefutable_let_patterns)]
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this pattern will always match, so the guard is useless
+   = help: consider removing the guard and adding a `let` inside the match arm
+
+error: unreachable pattern
+  --> $DIR/warns.rs:15:25
+   |
+LL |         x if let None | None = x => {}
+   |                         ^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/warns.rs:12:8
+   |
+LL | #[deny(unreachable_patterns)]
+   |        ^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+