Add new lint: strlen_on_c_strings

2 files changed, 12 insertions, 0 deletions

diff --git a/clippy_utils/src/paths.rs b/clippy_utils/src/paths.rs
index b913d1ce8b1..9ebfbd6b423 100644
--- a/clippy_utils/src/paths.rs
+++ b/clippy_utils/src/paths.rs
@@ -82,6 +82,7 @@ pub const ITER_REPEAT: [&str; 5] = ["core", "iter", "sources", "repeat", "repeat
 pub const KW_MODULE: [&str; 3] = ["rustc_span", "symbol", "kw"];
 #[cfg(feature = "internal-lints")]
 pub const LATE_CONTEXT: [&str; 2] = ["rustc_lint", "LateContext"];
+pub const LIBC_STRLEN: [&str; 2] = ["libc", "strlen"];
 pub const LINKED_LIST: [&str; 4] = ["alloc", "collections", "linked_list", "LinkedList"];
 #[cfg(any(feature = "internal-lints", feature = "metadata-collector-lint"))]
 pub const LINT: [&str; 2] = ["rustc_lint_defs", "Lint"];
diff --git a/clippy_utils/src/ty.rs b/clippy_utils/src/ty.rs
index a92d3be5d3c..9e271b71204 100644
--- a/clippy_utils/src/ty.rs
+++ b/clippy_utils/src/ty.rs
@@ -231,6 +231,17 @@ pub fn is_recursively_primitive_type(ty: Ty<'_>) -> bool {
     }
 }
 
+/// Checks if the type is a reference equals to a diagnostic item
+pub fn is_type_ref_to_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
+    match ty.kind() {
+        ty::Ref(_, ref_ty, _) => match ref_ty.kind() {
+            ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did),
+            _ => false,
+        },
+        _ => false,
+    }
+}
+
 /// Checks if the type is equal to a diagnostic item
 ///
 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`