1 files changed, 34 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/misc_early/mixed_case_hex_literals.rs b/src/tools/clippy/clippy_lints/src/misc_early/mixed_case_hex_literals.rs
new file mode 100644
index 000000000..80e242131
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/misc_early/mixed_case_hex_literals.rs
@@ -0,0 +1,34 @@
+use clippy_utils::diagnostics::span_lint;
+use rustc_ast::ast::Lit;
+use rustc_lint::EarlyContext;
+
+use super::MIXED_CASE_HEX_LITERALS;
+
+pub(super) fn check(cx: &EarlyContext<'_>, lit: &Lit, suffix: &str, lit_snip: &str) {
+    let maybe_last_sep_idx = if let Some(val) = lit_snip.len().checked_sub(suffix.len() + 1) {
+        val
+    } else {
+        return; // It's useless so shouldn't lint.
+    };
+    if maybe_last_sep_idx <= 2 {
+        // It's meaningless or causes range error.
+        return;
+    }
+    let mut seen = (false, false);
+    for ch in lit_snip.as_bytes()[2..=maybe_last_sep_idx].iter() {
+        match ch {
+            b'a'..=b'f' => seen.0 = true,
+            b'A'..=b'F' => seen.1 = true,
+            _ => {},
+        }
+        if seen.0 && seen.1 {
+            span_lint(
+                cx,
+                MIXED_CASE_HEX_LITERALS,
+                lit.span,
+                "inconsistent casing in hexadecimal literal",
+            );
+            break;
+        }
+    }
+}