add move expression parser ambiguity tests

tests/ui/move-expr/parse-ambiguity-errors.rs

@@ -0,0 +1,14 @@
+#![allow(incomplete_features)]
+#![feature(move_expr)]
+
+fn main() {
+    let x: bool = true;
+    let y: bool = true;
+    let _ = move(x) || y;
+    //~^ ERROR `move(expr)` is only supported in plain closures
+
+    let x: bool = true;
+    let y: bool = true;
+    let _ = move[x] || y;
+    //~^ ERROR expected one of
+}

tests/ui/move-expr/parse-ambiguity-errors.stderr

@@ -0,0 +1,14 @@
+error: expected one of `async`, `|`, or `||`, found `[`
+  --> $DIR/parse-ambiguity-errors.rs:12:17
+   |
+LL |     let _ = move[x] || y;
+   |                 ^ expected one of `async`, `|`, or `||`
+
+error: `move(expr)` is only supported in plain closures
+  --> $DIR/parse-ambiguity-errors.rs:7:13
+   |
+LL |     let _ = move(x) || y;
+   |             ^^^^
+
+error: aborting due to 2 previous errors
+

tests/ui/move-expr/parse-ambiguity.rs

@@ -0,0 +1,13 @@
+//@ check-pass
+#![allow(incomplete_features)]
+#![feature(move_expr)]
+
+fn main() {
+    let x: bool = true;
+    let y: bool = true;
+    let _ = || move(x) || y;
+
+    let x: bool = true;
+    let y: bool = true;
+    let _ = move || move(x) || y;
+}