fix(cargo-lint): Make im-a-teapot permanently unstable

src/cargo/util/lints.rs

@@ -1,6 +1,6 @@
 use crate::core::dependency::DepKind;
 use crate::core::FeatureValue::Dep;
-use crate::core::{Edition, FeatureValue, Package};
+use crate::core::{Edition, Feature, FeatureValue, Package};
 use crate::util::interning::InternedString;
 use crate::{CargoResult, GlobalContext};
 use annotate_snippets::{Level, Renderer, Snippet};
@@ -238,6 +238,15 @@ pub fn check_im_a_teapot(
     error_count: &mut usize,
     gctx: &GlobalContext,
 ) -> CargoResult<()> {
+    // This lint is only available when `test-dummy-unstable` is enabled
+    if !pkg
+        .manifest()
+        .unstable_features()
+        .is_enabled(Feature::test_dummy_unstable())
+    {
+        return Ok(());
+    }
+
     let manifest = pkg.manifest();
     let (lint_level, reason) = IM_A_TEAPOT.level(pkg_lints, ws_lints, manifest.edition());
     if lint_level == LintLevel::Allow {