Add failing test

src/test/ui/suggestions/dont-suggest-doc-hidden-variant-for-enum/auxiliary/other_crate.rs

@@ -0,0 +1,8 @@
+#![crate_type = "lib"]
+
+extern crate core;
+
+#[doc(hidden)]
+pub mod __private {
+    pub use core::option::Option::{self, None, Some};
+}

src/test/ui/suggestions/dont-suggest-doc-hidden-variant-for-enum/dont-suggest-doc-hidden-variant-for-enum.rs

@@ -0,0 +1,7 @@
+// aux-build:other_crate.rs
+
+extern crate other_crate;
+
+fn main() {
+    let x: Option<i32> = 1i32; //~ ERROR 6:26: 6:30: mismatched types [E0308]
+}

src/test/ui/suggestions/dont-suggest-doc-hidden-variant-for-enum/dont-suggest-doc-hidden-variant-for-enum.stderr

@@ -0,0 +1,16 @@
+error[E0308]: mismatched types
+  --> $DIR/dont-suggest-doc-hidden-variant-for-enum.rs:6:26
+   |
+LL |     let x: Option<i32> = 1i32;
+   |            -----------   ^^^^
+   |            |             |
+   |            |             expected enum `Option`, found `i32`
+   |            |             help: try using a variant of the expected enum: `Some(1i32)`
+   |            expected due to this
+   |
+   = note: expected enum `Option<i32>`
+              found type `i32`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.