feat(im-a-teapot): Error if specified but not enabled

Author: Muscraft

src/cargo/util/lints.rs

@@ -247,9 +247,39 @@ pub fn check_im_a_teapot(
     gctx: &GlobalContext,
 ) -> CargoResult<()> {
     let manifest = pkg.manifest();
+    let manifest_path = rel_cwd_manifest_path(path, gctx);
     let (lint_level, reason) = IM_A_TEAPOT.level(pkg_lints, ws_lints, manifest.edition());
 
     if IM_A_TEAPOT.is_feature_gated(manifest) {
+        if reason == LintLevelReason::Package || reason == LintLevelReason::Workspace {
+            *error_count += 1;
+            let span = get_span(
+                manifest.document(),
+                &["lints", "cargo", "im-a-teapot"],
+                false,
+            )
+            .or(get_span(
+                manifest.document(),
+                &["lints", "cargo", "im_a_teapot"],
+                false,
+            ))
+            .unwrap();
+            let message = Level::Error
+                .title("use of unstable lint `im-a-teapot`")
+                .snippet(
+                    Snippet::source(manifest.contents())
+                        .origin(&manifest_path)
+                        .annotation(Level::Error.span(span))
+                        .fold(true),
+                );
+            let renderer = Renderer::styled().term_width(
+                gctx.shell()
+                    .err_width()
+                    .diagnostic_terminal_width()
+                    .unwrap_or(annotate_snippets::renderer::DEFAULT_TERM_WIDTH),
+            );
+            writeln!(gctx.shell().err(), "{}", renderer.render(message))?;
+        }
         return Ok(());
     }
 
@@ -266,7 +296,6 @@ pub fn check_im_a_teapot(
             *error_count += 1;
         }
         let level = lint_level.to_diagnostic_level();
-        let manifest_path = rel_cwd_manifest_path(path, gctx);
         let emitted_reason = format!(
             "`cargo::{}` is set to `{lint_level}` {reason}",
             IM_A_TEAPOT.name

tests/testsuite/lints_table.rs

@@ -1100,11 +1100,15 @@ im-a-teapot = "warn"
 
     p.cargo("check -Zcargo-lints")
         .masquerade_as_nightly_cargo(&["cargo-lints"])
-        .with_status(0)
+        .with_status(101)
         .with_stderr(
             "\
-[CHECKING] foo v0.0.1 ([CWD])
-[FINISHED] [..]
+error: use of unstable lint `im-a-teapot`
+ --> Cargo.toml:9:1
+  |
+9 | im-a-teapot = \"warn\"
+  | ^^^^^^^^^^^
+  |
 ",
         )
         .run();