Migrate the issue-149402-no-suggest-unstable test from a run-make test to a UI test

Author: Kobzol

tests/run-make/issue-149402-suggest-unresolve/foo.rs

@@ -0,0 +1,15 @@
+error[E0433]: cannot find type `Complete` in this scope
+  --> $DIR/dont-suggest-unstable-type.rs:14:12
+   |
+LL |     x.push(Complete::Item { name: "hello" });
+   |            ^^^^^^^^ use of undeclared type `Complete`
+   |
+help: there is an enum variant `std::ops::CoroutineState::Complete`; try using the variant's enum
+   |
+LL -     x.push(Complete::Item { name: "hello" });
+LL +     x.push(std::ops::CoroutineState::Item { name: "hello" });
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0433`.

tests/run-make/issue-149402-suggest-unresolve/nightly.err

@@ -0,0 +1,18 @@
+//! Check that unstable name-resolution suggestions are omitted on stable.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/149402>.
+//!
+//@ needs-target-std
+//@ ignore-backends: gcc
+
+//@ revisions: stable nightly
+//@[stable] act-as-stable
+//@[nightly] only-nightly
+
+fn foo() {
+    let x = Vec::new();
+    x.push(Complete::Item { name: "hello" });
+    //~^ ERROR: cannot find type `Complete` in this scope
+}
+
+fn main() {}

tests/run-make/issue-149402-suggest-unresolve/output.diff

@@ -1,8 +1,8 @@
 error[E0433]: cannot find type `Complete` in this scope
- --> foo.rs:3:12
-  |
-3 |     x.push(Complete::Item { name: "hello" });
-  |            ^^^^^^^^ use of undeclared type `Complete`
+  --> $DIR/dont-suggest-unstable-type.rs:14:12
+   |
+LL |     x.push(Complete::Item { name: "hello" });
+   |            ^^^^^^^^ use of undeclared type `Complete`
 
 error: aborting due to 1 previous error