let_chains: Add feature gate tests.

2 files changed, 380 insertions, 0 deletions

diff --git a/src/test/ui/rfc-2497-if-let-chains/feature-gate.rs b/src/test/ui/rfc-2497-if-let-chains/feature-gate.rs
new file mode 100644
index 00000000000..cf4a44a9ce7
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/feature-gate.rs
@@ -0,0 +1,101 @@
+// 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 (let 0 = 1) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions only supported in `if`
+
+    if (((let 0 = 1))) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    if true && let 0 = 1 {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    if let 0 = 1 && true {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    if (let 0 = 1) && true {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    if true && (let 0 = 1) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    if (let 0 = 1) && (let 0 = 1) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+
+    if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+
+    if let Range { start: _, end: _ } = (true..true) && false {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+}
+
+fn _while() {
+    if let 0 = 1 {} // Stable!
+
+    while (let 0 = 1) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    while (((let 0 = 1))) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    while true && let 0 = 1 {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    while let 0 = 1 && true {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    while (let 0 = 1) && true {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    while true && (let 0 = 1) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+
+    while (let 0 = 1) && (let 0 = 1) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+
+    while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+    //~| ERROR `let` expressions in this position are experimental [E0658]
+
+    while let Range { start: _, end: _ } = (true..true) && false {}
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+}
+
+fn _macros() {
+    macro_rules! noop_expr { ($e:expr) => {}; }
+    noop_expr!((let 0 = 1));
+
+    macro_rules! use_expr {
+        ($e:expr) => {
+            if $e {}
+            while $e {}
+        }
+    }
+    use_expr!(let 0 = 1 && 0 == 0);
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    use_expr!((let 0 = 1));
+    //~^ ERROR `let` expressions in this position are experimental [E0658]
+    use_expr!(let 0 = 1);
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2497-if-let-chains/feature-gate.stderr b/src/test/ui/rfc-2497-if-let-chains/feature-gate.stderr
new file mode 100644
index 00000000000..f641429a6bb
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/feature-gate.stderr
@@ -0,0 +1,279 @@
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:14:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:18:11
+   |
+LL |     if (((let 0 = 1))) {}
+   |           ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:21:16
+   |
+LL |     if true && let 0 = 1 {}
+   |                ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:24:8
+   |
+LL |     if let 0 = 1 && true {}
+   |        ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:27:9
+   |
+LL |     if (let 0 = 1) && true {}
+   |         ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:30:17
+   |
+LL |     if true && (let 0 = 1) {}
+   |                 ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:33:9
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |         ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:33:24
+   |
+LL |     if (let 0 = 1) && (let 0 = 1) {}
+   |                        ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:37:8
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |        ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:37:21
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                     ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:37:35
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                   ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:37:48
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:37:61
+   |
+LL |     if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                             ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:44:8
+   |
+LL |     if let Range { start: _, end: _ } = (true..true) && false {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:51:12
+   |
+LL |     while (let 0 = 1) {}
+   |            ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:54:14
+   |
+LL |     while (((let 0 = 1))) {}
+   |              ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:57:19
+   |
+LL |     while true && let 0 = 1 {}
+   |                   ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:60:11
+   |
+LL |     while let 0 = 1 && true {}
+   |           ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:63:12
+   |
+LL |     while (let 0 = 1) && true {}
+   |            ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:66:20
+   |
+LL |     while true && (let 0 = 1) {}
+   |                    ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:69:12
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |            ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:69:27
+   |
+LL |     while (let 0 = 1) && (let 0 = 1) {}
+   |                           ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:73:11
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |           ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:73:24
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                        ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:73:38
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                      ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:73:51
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                   ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:73:64
+   |
+LL |     while let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) {}
+   |                                                                ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:80:11
+   |
+LL |     while let Range { start: _, end: _ } = (true..true) && false {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:94:15
+   |
+LL |     use_expr!(let 0 = 1 && 0 == 0);
+   |               ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error[E0658]: `let` expressions in this position are experimental
+  --> $DIR/feature-gate.rs:96:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+   = help: add #![feature(let_chains)] to the crate attributes to enable
+
+error: `let` expressions only supported in `if`
+  --> $DIR/feature-gate.rs:14:9
+   |
+LL |     if (let 0 = 1) {}
+   |         ^^^^^^^^^
+
+error: aborting due to 31 previous errors
+
+For more information about this error, try `rustc --explain E0658`.