Add diagnostic_item_path lint

clippy_lints/src/lib.register_internal.rs

@@ -8,6 +8,7 @@ store.register_group(true, "clippy::internal", Some("clippy_internal"), vec![
     LintId::of(utils::internal_lints::COMPILER_LINT_FUNCTIONS),
     LintId::of(utils::internal_lints::DEFAULT_DEPRECATION_REASON),
     LintId::of(utils::internal_lints::DEFAULT_LINT),
+    LintId::of(utils::internal_lints::DIAGNOSTIC_ITEM_PATH),
     LintId::of(utils::internal_lints::IF_CHAIN_STYLE),
     LintId::of(utils::internal_lints::INTERNING_DEFINED_SYMBOL),
     LintId::of(utils::internal_lints::INVALID_CLIPPY_VERSION_ATTRIBUTE),

clippy_lints/src/lib.register_lints.rs

@@ -14,6 +14,8 @@ store.register_lints(&[
     #[cfg(feature = "internal")]
     utils::internal_lints::DEFAULT_LINT,
     #[cfg(feature = "internal")]
+    utils::internal_lints::DIAGNOSTIC_ITEM_PATH,
+    #[cfg(feature = "internal")]
     utils::internal_lints::IF_CHAIN_STYLE,
     #[cfg(feature = "internal")]
     utils::internal_lints::INTERNING_DEFINED_SYMBOL,

clippy_lints/src/lib.rs

@@ -531,6 +531,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         store.register_early_pass(|| Box::new(utils::internal_lints::ProduceIce));
         store.register_late_pass(|_| Box::new(utils::internal_lints::CollapsibleCalls));
         store.register_late_pass(|_| Box::new(utils::internal_lints::CompilerLintFunctions::new()));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::DiagnosticItemPath));
         store.register_late_pass(|_| Box::new(utils::internal_lints::IfChainStyle));
         store.register_late_pass(|_| Box::new(utils::internal_lints::InvalidPaths));
         store.register_late_pass(|_| Box::<utils::internal_lints::InterningDefinedSymbol>::default());

clippy_lints/src/utils/internal_lints.rs

@@ -7,6 +7,9 @@ pub use collapsible_calls::{CollapsibleCalls, COLLAPSIBLE_SPAN_LINT_CALLS};
 mod compiler_lint_functions;
 pub use compiler_lint_functions::{CompilerLintFunctions, COMPILER_LINT_FUNCTIONS};
 
+mod diagnostic_item_path;
+pub use diagnostic_item_path::{DiagnosticItemPath, DIAGNOSTIC_ITEM_PATH};
+
 mod if_chain_style;
 pub use if_chain_style::{IfChainStyle, IF_CHAIN_STYLE};
 

clippy_lints/src/utils/internal_lints/diagnostic_item_path.rs

@@ -0,0 +1,50 @@
+use clippy_utils::def_path_res;
+use clippy_utils::diagnostics::span_lint_and_help;
+use rustc_ast::LitKind;
+use rustc_hir::{def::Res, Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for hardcoded paths to diagnostic items.
+    ///
+    /// ### Why is this bad?
+    /// See: https://github.com/rust-lang/rust-clippy/issues/5393
+    #[clippy::version = "1.66.0"]
+    pub DIAGNOSTIC_ITEM_PATH,
+    internal,
+    "hardcoded paths to diagnostic items"
+}
+
+declare_lint_pass!(DiagnosticItemPath => [DIAGNOSTIC_ITEM_PATH]);
+
+impl LateLintPass<'_> for DiagnosticItemPath {
+    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
+        if let ExprKind::Array(elements) = expr.kind
+            && let Some(path) = elements
+                .iter()
+                .map(|element| {
+                    if let ExprKind::Lit(lit) = &element.kind
+                        && let LitKind::Str(s, _) = lit.node
+                    {
+                        Some(s.as_str().to_owned())
+                    } else {
+                        None
+                    }
+                })
+                .collect::<Option<Vec<_>>>()
+            && let Res::Def(_, def_id) = def_path_res(cx, &path.iter().map(AsRef::as_ref).collect::<Vec<_>>())
+            && let Some(sym) = cx.tcx.get_diagnostic_name(def_id)
+        {
+            span_lint_and_help(
+                cx,
+                DIAGNOSTIC_ITEM_PATH,
+                expr.span,
+                "hardcoded path to a diagnostic item",
+                None,
+                &format!("rewrite the code to use `sym::{sym}`"),
+            );
+        }
+    }
+}

tests/ui-internal/diagnostic_item_path.rs

@@ -0,0 +1,11 @@
+#![allow(unused)]
+#![warn(clippy::diagnostic_item_path)]
+
+fn main() {
+    const DEREF_TRAIT: [&str; 4] = ["core", "ops", "deref", "Deref"];
+
+    const DEREF_TRAIT_METHOD: [&str; 5] = ["core", "ops", "deref", "Deref", "deref"];
+
+    // Not yet a diagnostic item
+    const DEREF_MUT_TRAIT_METHOD: [&str; 5] = ["core", "ops", "deref", "DerefMut", "deref_mut"];
+}

tests/ui-internal/diagnostic_item_path.stderr

@@ -0,0 +1,19 @@
+error: hardcoded path to a diagnostic item
+  --> $DIR/diagnostic_item_path.rs:5:36
+   |
+LL |     const DEREF_TRAIT: [&str; 4] = ["core", "ops", "deref", "Deref"];
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::diagnostic-item-path` implied by `-D warnings`
+   = help: rewrite the code to use `sym::Deref`
+
+error: hardcoded path to a diagnostic item
+  --> $DIR/diagnostic_item_path.rs:7:43
+   |
+LL |     const DEREF_TRAIT_METHOD: [&str; 5] = ["core", "ops", "deref", "Deref", "deref"];
+   |                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: rewrite the code to use `sym::deref_method`
+
+error: aborting due to 2 previous errors
+